space food technology,,,,

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Seminar (0+1)

Kerala Agricultural University

POST HARVEST TECHNOLOGY AND AGRICULTURAL PROCESSING

KELAPPAJI COLLEGE OF AGRICULTURAL ENGINEERING AND

TECHNOLOGY

TAVANUR-679573, MALAPPURAM

KERALA, INDIA

2014

A Seminar report on

SPACE FOOD TECHNOLOGY

COURSE TEACHER: Mrs: SREEJA.R

PRESENTED BY: AJNA ALAVUDEEN

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ACKNOWLEDGEMENT

First of all I bow my head before “THE ALMIGHTY” for the blessings showered

on me to successfully complete the endeavour. It is with great respect and devotion I place on

record my deep sense of gratitude and indebtedness to my seminar.

I place a deep sense of obligation to Mrs.Sreeja R., Asst.Prof. Department of

PHT&AP, for the help and cooperation received from him during the entire seminar.

I also express my sincere gratitude to Dr.Prince M.V., Asst.Prof. Department of

PHT&AP for providing relevant data on the topic.

Finally, I must acknowledge the great moral support I received from my friends in

getting the references and materials required for my seminar.

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CONTENTS

Abstract................................................................................................................4

Introduction..........................................................................................................5

Space food history................................................................................................6

On ward to mars (present)....................................................................................9

Nutrition..............................................................................................................10

Functional foods for space..................................................................................11

Types of food......................................................................................................13

Menu selection....................................................................................................16

Microgravity.......................................................................................................17

Application of food technology in space............................................................18

Packaging evolution and resource utilization.....................................................22

Space food system laboratory.............................................................................25

Space food safety................................................................................................26

Space food for future..........................................................................................27

Case study: 1.......................................................................................................28

Case study: 2.......................................................................................................42

Conclusion..........................................................................................................48

Reference............................................................................................................49

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ABSTRACT

Many people may wonder about what and how the astronauts eat aboard

the space shuttle and the space station. The foods they eat are not provided in tubes and they

are neither bland nor unsavoury. Food systems and menu items evolved tremendously since

the days of the mercury programme. Food technology spin offs benefit dining rooms

throughout the world. It is estimated that a food system for a long duration mission must

maintain organoleptic acceptability, nutritional efficacy, and safety for a 3 to 5 year period to

be viable. In addition, the current mass and subsequent waste of the food system must

decrease significantly to accord with the allowable volume and payload limits of the

proposed future space vehicles. Advancements in food packaging, preservation, preparation

and nutrient to meet the challenges of space resulted in many commercial products. Here’s a

look at the era of food systems, nutrition foods used, menu items selection, packaging, safety,

how, what, limitations and advancements in the field of space food technology.

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INTRODUCTION

Space food is a variety of food products, specially created and processed for

consumption by astronauts in outer space. The food has specific requirements of providing

balanced nutrition for individuals working in space, while being easy and safe to store,

prepare and consume in the machinery-filled low gravity environments of manned spacecraft.

In recent years, space food has been used by various nations engaging on space programs as a

way to share and show off their cultural identity and facilitate intercultural communication.

While starting a mission, there are many factors being considered, one such very important

thing is about their FOOD. Dining in space takes culinary art to new heights in orbit and on

Earth. With the zest of space technology, astronauts today are able to take in a variety of

tastes and textures that please their palates and satisfy their stomachs while orbiting hundreds

of miles from home.

Food needs to be edible throughout the voyage, and it also needs to provide

all the nutrients required to avoid vitamin deficiency diseases. But many of the current space

menu items do not maintain acceptability and nutritive value beyond 3 years. Longer space

missions require that the food system can sustain the crew for 3 to 5 years without

replenishment. However, space travel requires that new methods be devised for keeping

foods edible. For that, a number of technologies are adopted both for processing as well as

packaging, while these forms of food products are fine for travel for the mission. Moreover,

foods taken into space must be light-weight, compact, tasty and nutritious. They must also

keep for long periods without refrigeration. A variety of menus consisting of foods similar to

those displayed here provided each astronaut with 2500 or more calories per day. There are

many limitations to weight and volume when travelling and the microgravity conditions

experienced in space also affect the food packaging. Currently, there is limited storage space

and no refrigeration. To meet these challenges, special procedures for the preparation,

packaging, storing of food for space flight were developed. Moreover for each space

programmes like mercury, Gemini, Apollo, Skylab, space shuttle and international space

station (ISS) respectively have used different fooding system .So a lot of improvements had

experienced from processing as well as packaging from mercury to ISS .

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SPACE FOOD HISTORY

The food that NASA’s early astronauts had to eat in space is a testament to

their fortitude. John Glenn, America’s first man to eat anything in the near-weightless

environment of Earth orbit, found the task of eating fairly easy, but the menu limited.

1. Mercury :-( 1962-1964)

Mercury was the United States’ first space program that sent humans to space.

Astronauts in later Mercury missions disliked the food that was provided. They ate bite-sized

cubes, freeze-dried powders, and tubes of semi liquids. The astronauts found it unappetizing,

experienced difficulties in rehydrating the freeze-dried foods, and did not like having to

squeeze tubes or collect crumbs.here the flavour was unchanged,but the texture was

significantly different from the original product.

2. GEMINI :-( 1965-1967)

Project Gemini, was created to bring NASA one step closer to going to the moon.

Gemini missions eating improved somewhat. Bite-sized cubes were coated with gelatine to

reduce crumbling, and the freeze-dried foods were encased in a special plastic container to

make reconstituting easier. With improved packaging came improved food quality and

menus. Gemini astronauts had such food choices as shrimp cocktail, chicken and vegetables,

butterscotch pudding, and apple sauce, and were able to select meal combinations

themselves.

3. APOLLO :-( 1968-1975)

For the Apollo program -- the first to land men on the moon -- NASA provided its

astronauts with hot water, which made rehydrating foods easier. The Apollo astronauts were

also the first to have utensils and no longer had to squeeze food into their mouths. The

mission introduced the spoon, a plastic container with dehydrated food inside. After the

astronauts injected water into the bowl to rehydrate the food, they opened a zipper and ate the

food with a spoon. The wetness of the food made it cling to the spoon instead of floating

away. The Apollo mission also introduced thermo stabilized pouches called wet packs. These

flexible plastic or aluminium foil pouches kept food moist enough so that it didn't have to be

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rehydrated. The Apollo crew was able to dine on bacon squares, cornflakes, beef sandwiches,

chocolate pudding and tuna salad.

4. SKYLAB :- (1973-197)

The goals of the Skylab program were to prove that humans could live in space

for long periods of time, and to perform scientific experiments. Skylab had one of the best

space food systems. Larger living areas on the Skylab space station allowed for an on-board

refrigerator and freezer, which allowed perishable and frozen items to be stored. Food

containers for the Skylab astronauts consisted of aluminium cans with full panel pull-out lids.

Cans containing thermo stabilized food had a build-in membrane to prevent spillage when

removing the lid in can and had a water valve for rehydration. Canned, ready-to-eat foods

were held in the can with a slit plastic cover. Instead of plastic drinking bags, Skylab drinking

containers were collapsible bottles that expanded accordian style when filled with hot or cold

water. Because of its relatively large storage space, Skylab was able to feature an extensive

menu of 72 different food items. Unique to Skylab were a freezer for foods such as filet

mignon and vanilla ice cream and a refrigerator for chilling fruits and beverages. To prepare

meals, the Skylab crew placed desired food packages into the food warmer tray. This was the

first device capable of heating foods (by means of conduction) during space flight. Foods

consisted of products such as ham, chilli, mashed potatoes, ice cream, steak and asparagus

etc.

5. Apollo-Soyuz docking mission

The Apollo spacecraft did not have the freezer that Skylab featured but many of the

food advances from Skylab and the earlier Apollo missions were incorporated. Because of the

short duration of the flight (nine days), many short shelf-life items were added to the foods

carried. Fresh breads and cheese were included as a part of 80 different varieties of food

dined upon by the Apollo while others were placed in spoon-bowl packages or plastic

drinking bags. To make eating easier, a food tray was carried on the mission. The tray did not

warm the food as the Skylab tray did, but it held the food in place with springs and Velcro

fasteners. The tray was secured to the crewmember's leg during meal time.

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6. SPACE SHUTTLE :-( 1982)

Here, meals looked almost identical to what astronauts ate on Earth. Astronauts

designed their own seven day menus selected from 74 different foods and 20 drinks. They

prepared their meals in a galley with a water dispenser and an oven. Irradiated foods joined

the major categories of consumables, primarily to make meats safer, as they had to be stored

at lower-than-refrigerated temperatures.

7. INTERNATIONAL SPACE STATION (ISS) :-( 1998)

The International Space Station (ISS) is a giant environment for living. Most

consumables on the international space are canned, frozen or wrapped in sealed packs. The

fuel cells, which provide electrical power for the Space Shuttle, produce water as a by-

product, which is then used for food preparation and drinking. However, on the ISS, the

electrical power will be produced by solar arrays. This power system does not produce water,

water will be recycled from a variety of sources, but that will not be enough for use in the

food system. Therefore, most of the food planned for the ISS will be frozen, refrigerated, or

thermostabilized (heat processed, canned, and stored at room temperature) and will not

require the addition of water before consumption An adapter located on the packagewill

connect with the galley, or kitchen area, so that water may be dispensed into the package.

This water will mix with the drink powder already in the package. The adapter used to add

water also holds the drinking straw for the astronauts. The food package is made from a

microwaveable material. The top of the package is cut off with a pair of scissors, and the

contents are eaten with a fork or spoon. Spicy food turns to be favourite. Thus, richly

flavourful items like shrimp with tangy sauce, or jambalaya with garlic beans are preferred

the longer astronauts are in orbit.

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ONWARDS TO MARS - PRESENT

Menus are designed to fulfil the nutritional requirements of crews in terms of

days, weeks or months at a time on the ISS. Of course, the Space Station is quite close to

Earth, and re-supply vehicles are comparatively easier to come by than they would be on a

mission to Mars, which might last 2-3 years. The new goal will be to create foodstuffs that

last far longer than the 12-24 month shelf-life they have now, but can they still make them

light, edible, transportable, safe and nutritious? We all know that science improved a lot, and

we can definitely say that science has its influence in almost all fields of human activities.

Here the question arrives, can’t plants grow on the surface of mars? It is impossible, why

because the average surface temperature of mars is -60˚F.But their application of science

technology arrives, i.e.; the crop will be either grown hydroponically or airoponically.

a) HYDROPONICS SYSTEM

HYDROPONICS is a subset of hydro culture and is a method of growing plants

using mineral nutrient solutions, in water, without soil. Scientists are trying to find a way to

adequately feed them. As we haven’t yet found soil that can support life in space, and the

logistics of transporting soil are impractical, hydroponics could hold the key to the future of

space exploration. The benefits of hydroponics in space are two-fold: It offers the potential

for a larger variety of food, and it provides a biological aspect, called a bio regenerative life

support system. This simply means that as the plants grow, they will absorb carbon dioxide

and stale air and provide renewed oxygen through the plant's natural growing process. This is

important for long-range habitation of both the space stations and other planets.

b) AEROPONIC SYSTEM

AEROPONICS systems, which utilize a high-pressure pump to spray

nutrients and water onto the roots of a plant, may be an essential part of space missions in the

future. Aeroponic growing systems provide clean, efficient, and rapid food production. Crops

can be planted and harvested year round without interruption, and without contamination

from soil or pesticide use. Plants grown in aeroponic systems have also been shown to take in

more vitamins and minerals, making the plants healthier and potentially more nutritious.

These ‘space gardens’ could provide up to half of the required calories for the astronauts

though tomatoes, potatoes, and other fruits and vegetables. It can also help to recycle

nutrients, provide drinking water and create oxygen in space.

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NUTRITION

Food provides the nutrients that human beings need to maintain their

health. Getting enough calories, vitamins and minerals is as important for astronauts as it is

for people living on Earth. The space food systems supply a more limited variety of items

than one would find in the grocery store here on Earth, so menu planning is very important to

make sure the astronauts can get the nutrients they need from their food. The nutrients

astronauts need in space are the same ones all people need, but the amounts of some differ.

Astronauts need the same number of calories of energy during spaceflight as they need on the

ground. Most of the vitamins and minerals they need are the same as on the ground. The

amount of iron in an astronaut’s diet should be less than10 milligrams per day for both men

and women. Most of the ion absorbed from food goes into new red blood cells. If astronauts

were to eat foods high in iron, the iron would be stored in their bodies and could cause health

problems. Sodium and vitamin D affect bone. The amount of sodium in the astronauts’ diet is

limited because too much can lead to boneless as well as other health problems. The body

usually makes vitamin D when the skin is exposed to sunlight, but spacecraft are shielded to

protect the astronauts from harmful radiation.. As the body adapts to weightlessness, many

physiological changes occur. Many of these can affect nutrition or be affected badly it. The

changes include loss of bone and muscle, changes in heart and blood vessel function, and

changes in blood and the amount of fluid in different areas of the body. Astronauts usually

lose weight during spaceflight. Being sure they eat enough calories is important, because if

they eat enough calories, they will also eat enough of most other nutrients, including vitamins

and minerals. For ISS crewmembers, it is important that they begin their mission in excellent

health, maintain that state of health as much as possible, and then get back to it as quickly as

possible after the mission. ISS crewmembers have their nutritional status checked before,

during and after flight to help reach this goal. Before and after flight, blood and urine samples

from crewmembers are analyzed for chemicals that indicate nutritional status .During the

mission, crewmembers fallout a computerized Food Frequency Questionnaire to report what

foods they have eaten during the previous week. The computer results are sent electronically

to the ground, and nutrition specialists analyze the data right way so they can recommend

ways to improve the astronauts’ dietary intake. As mission lengths increase from weeks on

the shuttle to several months on the ISS and perhaps two years on a mission to another planet,

nutrition become many more important.

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FUNCTIONAL FOOD FOR SPACE

It is well documented that, during space missions, the human body is

subjected to extreme stress, both physiological and psychological, that may negatively impact

health. Multiple risks are associated with space flight including exposure to microgravity,

increased ionizing radiation levels as well as living in a small, confined environment. These

stresses imposed by space travel on the human body make it particularly difficult to ensure

the health of the crew members especially in longer missions. It is therefore imperative to use

whatever means available to protect the crewmembers, and in this context food becomes a

tool of paramount importance. Food provides not only the nutrients necessary to fulfil the

physiological needs of the astronauts but also the following: a familiar element in an

unfamiliar and hostile environment, a reminder of home, a break from work, and an

important social activity for the crew.

Unfortunately up to the present, the food intake of astronauts has been

below the minimum recommended level (e.g. 50 % lover energy intake in Shuttle; 13). This

lack of adequate consumption has been associated with the very busy schedule of the

astronauts during missions and, consequently, their tendency to skip meals; 13). In addition,

in microgravity astronauts are subject to a significant decrease in taste and odour sensitivity

(possible consequence of the body-fluids shift towards the head induced by the lack of

gravity) that could affect appetite and eating habits. The challenge for the space-food

scientists is to produce appetizing food items that tempt the astronaut increasing the

anticipation towards meal time and increasing their food intake.

In recent years there has been an increasing awareness of the role of

food as a tool to improve well-being and as means to prevent and counteract specific

pathologies. Specific components of food products have been isolated and proven to have

some beneficial effect on the body. This new vision of food has become popular with

consumers and has led the food industry towards development of foods with positive health

properties. A food so formulated is called “functional food”.

The addition of functional foods targeted to astronauts for consumption

during space missions is advisable to help mitigate the deleterious effects of space flight on

the human body. Such foods would not only provide the appropriate nutrients to the

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astronauts but they could also be specifically designed to be rich in ingredients with

functional properties.

Development of functional foods for space travel should focus on the following properties:

High antioxidant activity: antioxidants act in concert as the body’s defence against

free radical damage. A number of studies have shown that adding an antioxidant to

the diet can modify the radio sensitivity of human cells in ground-based models.

High in water: It is essential for crew members to consume adequate amounts of

fluids. The current recommendation is for a minimum of 2 litres/day. Fulfilment of

this requirement can be quite difficult because reduced thirst (consequence of body-

fluids shift) is common in space flights and causes a low fluid intake (16, 14).

Slow energy release: Slow energy release would provide energy support to the body

for extended periods of time (e.g. extravehicular activity) and would help maintaining

high levels of attention

High in fibre content: dietary fibre, and in particular prebiotic fibres, reduce

constipation and prevent intestinal dismicrobisms.

Rich in bio available calcium: dietary calcium should be provided in adequate

quantities for preserving bone quality and quantity. The risk of kidney stones is low

enough and does not indicate that calcium intake should be lowered.

Low in sodium: excessive sodium intake during space flight may be problematic

because sodium exacerbates bone loss and dietary sodium recommendation for the

space flight. The reduction of sodium in the food supply is difficult since sodium

chloride is not only the responsible for salty taste but it is often used to increase shelf

life of a product.

Our research group has, therefore, been working on a research project

aiming at the creation of three highly acceptable, nutritionally dense, stable functional space

food products. Functional ingredients have been used to enhance the nutritional value of food

beyond basic calories and nutrient content by incorporating and maximizing the use of food

ingredients of high nutritional interest. The functional food products that have been

developed are a blueberry gel-like snack, nutritionally enhanced tortillas and nutritionally

enhanced pasta sheets and lasagne.

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TYPES OF FOOD

There are eight categories of space food;

1. Rehydratable Food:

Rehydratable items include both foods and beverages. One way weight can be conserved

during launch is to remove water in the food system. During the flight, water is added back to

the food just before it is eaten. The shuttle obiter fuel cells, which produce electricity by

combining hydrogen and oxygen, provide ample water for rehydrating foods as well as

drinking and a host of other uses. Foods packaged in rehydratable containers include soups

like chicken consomme and cream of mushroom; casseroles like macaroni and cheese and

rice and chicken; appetizers like shrimp cocktail; and breakfast foods like scrambled eggs and

cereals. Breakfast cereals are prepared by packaging the cereal in a rehydratable package with

non-fat dry milk and sugar, if needed. Water is added to the package just before the cereal is

eaten.

2. Thermostabilized Food:

Thermostabilized foods are heat processed to destroy harmful

microorganisms and enzymes. Individual servings of thermostabilized foods are

commercially available in aluminium or bimetallic cans, plastic cups, or in flexible retort

pouches. Most of the fruits, and fish such as tuna and salmon, are thermostabilized in cans.

The cans have easy-open, full-panel, and pull-out lids. Puddings are packaged in plastic cups.

Most of the entrees are packaged in flexible retort packages. This includes products such as

beef tips with mushrooms, tomatoes and eggplant, grilled chicken and ham. After the pouches

are heated, they are cut open with scissors. The food is eaten directly from the containers with

conventional eating utensils.

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3. Intermediate Moisture Food:

Intermediate moisture foods are preserved by restricting the amount of water

available for microbial growth, while retaining sufficient water to give the food a soft texture

and let it be eaten without further preparation. Water is removed or its activity restricted with

water binding substance such as sugar or salt. Intermediate moisture foods usually range from

15to 30 percent moisture, but the water present is chemically bound with the sugar or salt and

is not available to support microbial growth. Dried peaches, pears, and apricots, and dried

beef are examples of this type of shuttle food.

4. Natural Form Food:

Foods such as nuts, granola bars, and cookies are classified as natural form

foods. They are ready to eat, packaged in flexible pouches, and require no further processing

for consumption in flight. Both natural form and intermediate moisture foods are packaged in

clear, flexible Packages that are cut open with scissors.

5. Irradiated Food:

Beef steak and smoked turkey are the only irradiated products currently used

on the shuttle. The food is cooked, packaged inflexible, foil-laminated pouches, and sterilized

by exposure to ionizing radiation so they are stable at ambient temperature.

6. Frozen Food:

These foods are quick frozen to prevent build-up of large ice crystals. This

maintains the original texture of the food and helps it taste fresh. Examples include quiches,

casseroles, and chicken pot pie.

7. Fresh Food:

These foods are neither processed nor artificially preserved. Examples include

apples and bananas.

8. Refrigerated Food:

These foods require cold or cool temperatures to prevent spoilage. Examples

include Cream cheese and sour cream so they can be kept.

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Rehydratable food

2. Different types of food system

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MENU SELECTION

Early space voyagers were allowed to select their own personal menu from

limited number of flight-qualified foods. During the design phase of the Shuttle food system,

it was determined that a universal menu would be more appropriate, due to the larger crew

sizes and increased flight rate. A universal menu was selected after a series of sensory

evaluations by representative astronauts. Each meal was overwrapped in a plastic bag to keep

everything together. Experience with more flights resulted in more complaints about the

universal menu and the bagged meal, Each astronaut wanted to select his or her own menu

prior to the mission and did not want to be restricted to a sacked meal. Even though a few

commanders have dictated use of the universal menu for the convenience of food preparation,

the majority of flight crews prefer the personal preference menu. The system was changed

early in 1984 to allow crews the option of choosing the universal menu or their own. There is

no universal menu and crews must have options for menu selection with some real-time

decision capability.

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MICROGRAVITY

Food and how it is eaten and packaged have been greatly affected by the

unique microgravity environment of space. A microgravity environment is one in which

gravity s effects are greatly reduced. Microgravity occurs when a spacecraft orbits Earth. The

spacecraft and all its contents are in a state of free-fall. This is why a handful of candy seems

to the Space Shuttle when it is released. The candy does not drop to the floor of the Shuttle

because the floor is falling, too. Because of this phenomenon, foods are packaged and served

to prevent food from moving about the Space Shuttle or ISS.Crumbs and liquids could

damage equipment or be inhaled. Many of the foods are packaged with liquids. Liquids hold

foods together and, freed from containers, cling to themselves in large drops because of

cohesion. It is similar to a drop of water on piece of wax paper. The only difference is that

this drop of water is moving about the microgravity environment of the Space Shuttle.

Special straws are used for drinking the liquids. They have clamps that can be closed to

prevent the liquids from creeping out by the processes of capillary action and surface tension

when not being consumed. Microgravity also causes the utensils used for dining to float away

magnets on the food tray when they are not being used. The effects of microgravity have had

an enormous impact on the development of space food packaging, food selection etc.

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APPLICATION OF FOOD TECHNOLOGY IN SPACE

Goals;

1. Provide an adequate food system

Develop a safe food system.

Develop a nutritious food system.

Develop an acceptable food system.

2. Provide a food system that efficiently balances vehicle resources

Minimize volume.

Minimize mass.

Minimize power.

Minimize trace gas emission.

Minimize crew time.

Development of space food in the United States has evolved over a

series of manned missions into space in various types of vehicles with a wide variety of

objectives and goals. Man’s first ventures into space were in small space craft with a crew of

one or two. Food development for space flight has always been from a systems approach,

since the food has so many intricate interfaces in the closed environment of a spacecraft. The

design goals, from the consumer Point of view, have always been basically the same and are

not any different from those of the general public. These goals are:

High Acceptability

Minimum Preparation

Nutritious

Easy Clean-up

Free Choice

Engineered Foods

The initial approach to developing food to meet the constraints of the small

spacecraft was to produce highly engineered foods. Tube foods were the first to be consumed

in space by U.S. astronauts. Astronaut John Glenn was the first to eat in space when he had

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applesauce in a tube. Tubes were later supplemented with cubes. Both types of foods were

highly engineered and met all the constraints imposed by the vehicle, such as pressure

changes, high oxygen content, etc. There were virtually no crumbs associated with

consumption, no possibility of water escaping into the cabin, and the food provided a

balanced diet. But there was a problem, In order for food to be nutritious and provide

psychological well being, it must be eaten. Food in tubes could not be seen or smelled and the

texture was not normal in most cases. Cubes were made from crackers and cookies. The

flavour was unchanged, but the texture was significantly different from the original product.

Even though astronauts on taste panels in the test kitchen thought they tasted great, a majority

of the cubes were returned after each mission. Concentrated food or the meal-in-a-pill

concept was not acceptable for space food systems.

Heating Food

As food systems evolved from cubes and tubes to dehydrated foods, the need

for hot water or a method of heating food in space became apparent. Hot water was available

on the early space craft and methods were devised to add hot water to food for rehydration.

However, the water was seldom hot enough to provide a “hot” meal, especially after it was

transferred to a package with ambient temperature food and then allowed to sit for up to ten

minutes while the food rehydrated. A food warmer was first introduced on the Skylab

programming 1973. With mission length lasting up to84 days, the ability to heat food became

an important factor in the acceptability of the food. The Skylab food warmer was built into

the serving tray with three food cavities having the ability to warm. A food heater was not

used again until the Shuttle program, which began in 1981. The first food warmer used on the

Shuttle was portable carry-on suitcase heater. Hot water was not available from the tap, so in

order to get hot water, the astronauts had to fill a beverage package with ambient temperature

water and place it in the food warmer for 15 to 20 minutes. The galley was introduced on

STS-9in 1983. In addition to having the capability to heat foods in the forced-air convection

oven, the galley also provided measured quantities of hot and cold water, and a food

preparation area Plans for the Space Station galley include forced-air convection oven with

the capability to reach 350˚F. The ability to heat food significantly improves the

acceptability.

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Refrigerators and Freezers

A passive freezer, which used liquid nitrogen as the coolant, was

developed for the Apollo program, but was never used due to weight and volume restrictions.

Freezers and refrigerators were first used by the U.S. on the Skylab program, which began in

1973. Frozen and refrigerated foods enhanced the Skylab food system, which tended to be

bland and lacked variety due to the metabolic studies which controlled food intake. Only a

limited quantity of frozen and refrigerated food could be included, so the astronauts were

involved in the decision as to which foods would be frozen. The refrigerator was used as a

chillers for food preparation. The two most popular frozen foods were steaks and ice cream.

Food freezers and refrigerators were not included in the design of the Shuttle food system due

to limited weight and volume allocations. Three servings of vanilla ice cream and done steak

were sent up in a laboratory experimental freezer on STS-4. No other frozen food has been

used on U.S. missions since the Skylab program. Frozen and refrigerated foods have been

included in the plan for Space Station food. Current plans call for around 50 percent frozen

food for the 90-day missions. So Food freezers and refrigerators are essential for long

duration missions.

Thermo-stabilized Retort Pouches

The first retort pouches were used by NASA in 1968 on the Apollo Missions,

long before they were approved for the general public. Even though the pouches added more

weight and volume to the food system, the variety and minimum preparation efforts made the

retort pouches a favourite. Retort pouches have continued to be used in space food systems

from Apollo through the current Mars program.

Irradiated Food

Some irradiated foods offer a distinct advantage for use in space food systems.

They require no freezer or refrigerator space and allow the processor to control the amount

offered liquids and doneness in meat products, Shelf life of bakery goods is significantly

improved with irradiation. Irradiated ham was first used on Apollo17 in 1972. Irradiated flour

was used to make shelf stable bread for Skylab, and irradiated steak, ham, and corned beef

were used on the Apollo-Soyuz Test Project in 1975. Irradiated bread and breakfast rolls

were used on the early Shuttle missions, but were discontinued when permission was granted

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to load perishable food son the Shuttle at 16 hours before launch. Irradiated steak, corned

beef and smoked turkey have been used on Shuttle missions. Irradiated ham was first used

on Apollo17 in 1972. Irradiated flour was used to make shelf stable bread for Skylab, and

irradiated steak, ham, and corned beef were used on the Apollo-Soyuz Test Project in 1975.

Irradiated bread and breakfast rolls were used on the early Shuttle missions, but were

discontinued when permission was granted to load perishable foods on the Shuttle at 16 hours

before launch. Irradiated steak, corned beef and smoked turkey have been used on Shuttle

missions.

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PACKAGING EVOLUTION AND RESOURCE UTILIZATION

During the development of a space flight food system, many resources must be

considered. These include:

mass

volume

crew time

water use

waste disposal capacity

Ineffective use of vehicle resources will decrease the possibility of mission

success. Due to the lengthening of mission duration and lack of refrigeration, foods are

required to be shelf-stable. The production of by-product water from fuel cells on the Shuttle

brought about the development of freeze dried foods. Apollo era hard plastic spoon bowls

were reduced and replaced with a clear flexible plastic laminate. Rigid cans were replaced

with a flexible laminate with an aluminium foil layer for thermo stabilized foods. These new

flexible packages reduced mass and volume requirements during storage.

Food packaging is a major contributor to mass, volume and waste

allocations for NASA missions. Packaging is integral to maintaining the safety, nutritional

adequacy and acceptability of food, protecting it from foreign material, microorganisms,

oxygen, light, moisture and other modes of degradation. Higher packaging barrier properties

equate to greater food protection from oxygen and water ingress. Oxygen ingress can result in

oxidation of the food and loss of quality or nutrition. Water ingress can result in quality

changes such as difficulty in rehydrating freeze-dried foods and increased enzymatic and

microbiological activity. Clear, flexible, plastic laminate is currently used for freeze-dried

and natural form foods. This packaging enables a visual product inspection. This clear plastic

laminate is also able to be thermoformed and thermo sealed without flex cracks that are

common with foil laminates. That being said, the clear packaging does not have adequate

oxygen and moisture barrier properties to allow for an 18 month shelf-life for ISS missions.

Foods are overwrapped with a second, opaque foil containing package that has higher barrier

properties. The packaging materials used for the thermo stabilized, irradiated and beverage

items contain a foil layer that protects the food from oxygen and moisture beyond the

required 18-month shelf-life.

23

The oxygen and water vapour permeability of current NASA food packaging materials are

listed in tables

Oxygen Permeability of Packaging Materials (CC/100IN_2/DAY)

73.4°F @ 100% Relativity Humidity

Overwrap 0.0065

Thermo stabilized and Irradiated pouch <0.0003

Rehydratable Lid and Natural Form 5.405

Rehydratable bottom (heat formed) 0.053

Vapour Permeability of Packaging Materials (G/100IN_2/DAY)

100°F @ 100% Relativity Humidity

Overwrap <0.0003

Thermo stabilized and Irradiated pouch 0.0004

Rehydratable Lid and Natural Form 0.352

Rehydratable bottom (heat formed) 0.1784

A significant resource concern lies with the mass of the system. Mass of

the food is dependent on the type of food taken and the quantity required per crew member.

The Apollo food system provided 0.82 kg of food per crew member per day. Thermo

stabilized foods were included starting in 1968. These were preferred to freeze-dried options,

which justified the weight increase. By Apollo 14, food averaged 1.1 kg per crew member per

day. The Apollo food system still contained a significant number of freeze dried foods since

water from the fuel cells was available for rehydration (Evidence Category III). Current ISS

crew members receive approximately 1.8 kg of food per person per day (this number includes

packaging). Due to crew preference, a higher percentage of the food is thermo stabilized

(compared to Apollo era missions). This contributes to the weight increase. Since the ISS

24

used solar power instead of fuel cells that produce water, there is little mass advantage to

using freeze-dried foods.

The average caloric requirement for each crew member is now 3,000 kcal,

as opposed to 2,500 kcal provided for the Apollo crews. The actual, number of calories

allocated for each crew member is now based on the actual caloric needs of each crew

member, according to weight and height. This has caused a food weight increase.

25

Space Food Systems Laboratory (SFSL)

The Space Food Systems Laboratory is a multipurpose laboratory responsible for

space food and package research and development. This facility designs, develops, evaluates

and produces flight food, menus, packaging, and food-related ancillary hardware for Shuttle,

Space Station, and Advanced Food Systems. Capabilities of this facility include: food product

development, food preservation technology, sensory evaluation, menu planning, freeze

dehydration, blast freezing, package development, fabrication and design of packaging

equipment, physical testing of packages and materials, and modified and controlled

atmosphere packaging.

Space Mission / Purpose

Evidence strongly supports the role of nutrition in maintaining the health and

optimal performance of astronauts during space flights and return to Earth. The key to

providing good nutrition in support of human space flight is to provide high-quality food

products that are appetizing, nutritious, and safe and easy to prepare and eat. The mission of

the Space Food Systems Laboratory is to provide high-quality flight food systems that are

convenient, compatible with each crew member's physiological and psychological

requirements, meet spacecraft stowage and galley interface requirements, and are easy to

prepare and eat in the weightlessness of space.

Technical Specifications of Facility

The Space Food Systems Laboratory is located in Building 17 at Johnson Space

Centre and is comprised of four laboratories: a Test Kitchen, fully equipped with sensory

testing capabilities; a Food Processing Laboratory (Pilot Plant); a Food Packaging

Laboratory; and an Analytical Laboratory. The Space Food Systems Laboratory has the

capability to fabricate custom-moulded flight food containers; process foods using a variety

of stabilization techniques, including freezing and freeze-drying; package foods in a nitrogen

environment for long-term storage; provide long-term controlled environment storage for

processed foods; conduct physical and sensory analyses of food; evaluate prototype and flight

food preparation hardware; and, develop food preparation and serving techniques for space

flight.

26

FOOD SAFETY

Faced with the problem of how and what to feed an astronaut in a sealed

capsule under weightless conditions while planning for human space flight, NASA enlisted

the aid of The Pillsbury Company to address two principal concerns: eliminating crumbs of

food that might contaminate the spacecraft’s atmosphere and sensitive instruments, and

assuring absolute absence of disease-producing bacteria and toxins. Pillsbury developed the

Hazard Analysis and Critical Control Point (HACCP) concept to address NASA’s second

concern. HACCP is designed to prevent food safety problems rather than to catch them after

they have occurred. The U.S. Food and Drug Administration have applied HACCP guidelines

for the handling of seafood, juice, and dairy products.

27

SPACE FOOD FOR FUTURE

In the future, NASA is looking to send astronauts to outposts on the moon

and Mars. Although the target for liftoff for the moon mission is not until 2020, efforts are

already under way at the Space Food Systems Lab. Scientists in the Advanced Food

Technology group, led by NASA food scientist Michele Perchonok, are developing foods that

are nutritious, good tasting, and provide variety for a 3-year mission. “The biggest challenge

for these future missions is a food’s shelf life˝. For an initial trip to Mars, you will need

products that have a 5-year shelf life,” Kloeris says. The only foods that have currently

shown such a long shelf life are a few thermo stabilized foods, which is not enough to

provide a balanced diet, Kloeris says Perchonok and her team are looking always to improve

packaging materials that will provide a better barrier to water and oxygen—which can cause

food to spoil. This way, the shelf life for many current food items can be extended. Another

area of research is to develop ways to transport some foods—such as wheat berries and

soybeans—in bulk to reduce the amount of packaging materials used and to minimize waste.

“A 1,000-day mission to Mars for a crew of six will need about 10,000 kilograms if we went

with our packaged food system,” Perchonok says. “If we can save on that by growing some

items, by bringing some items up in bulk, it will be a lot easier.”

28

CASE STUDY-1

Assessment of the Long-Term Stability of Retort Pouch Foods to

Support Extended Duration Spaceflight

Beom-seok song et al

Introduction

The Advanced Food Technology (AFT) Project of the National Aeronautics and

Space Administration (NASA) Human Research Program (HRP) is currently working to

design a stable, palatable, and nutritious food supply to support long-duration spaceflight. A

large part of this food supply is expected to be positioned, unrefrigerated, at relevant

destination sites prior to crew arrival .Therefore, AFT anticipates that the food products used

on the emissions must maintain acceptable quality for a minimum of 3 to 5 y at ambient

conditions. The current spaceflight food system, designed to support short duration

spaceflight, consists of an assortment of retorted foods, intermediate moisture foods, freeze-

dried foods, and irradiated foods (Perchonok 2002). Of these, retort-processed pouch

products have the highest acceptability, and the greatest potential to maintain this

acceptability, in addition to safety and nutritive value, for 3 to 5 y. To this point, however,

there has been no quantitative shelf life testing completed on the entirety of NASA’s retorted

products. Such data are desired by NASA, to aid in assessing the compatibility of the current

short-duration menu with future plans for extended-duration spaceflight. While the

technology still relies on aggressive application and penetration of heat throughout foods,

recent advancements in process engineering coupled with evolution of packaging

technologies have allowed for an overall improvement of the technology (Lopez1987;

Goddard 1994; Brody 2002; Jun and others 2006). The current state of the art in retort pouch

processing has increased commercial value, and can offer to consumers a level of quality,

safety, and convenience not realized by other means (Brody 2002).Recent work has also

suggested that the unique properties of retort pouches allow for maximum heat penetration,

and reduction of nutrient losses associated with standard processing of cans (Chiaand others

1983; Lopez 1987). Additionally, as acknowledged by NASA, retort pouch products are

efficient in their distribution and have a limited impact on mission-critical resources, such as

launch mass and stowage volume (Perchonok 2002; Perchonokand Bourland

29

2002).Deterioration of foods throughout storage is considered a function of 4 general

phenomena: enzymatic, microbial, chemical, and physical processes (Kuntz 1994). Standards

of Identity, consumer expectations, and, often, nutrient content claims. NASA risk

assessment has also identified the importance of food system acceptability and nutrient

stability as integral to maintaining successful performance in missions (Perchonok and

Bourland 2002). Therefore, the objectives of this study were to furnish data on the chemical

and physical stability of NASA’s 65 retort processed foods, and to assess the feasibility of

using them to support long-duration missions. The study proceeded first by establishing

principle modes of deterioration, corresponding Q10 values, and ambient shelf life values for

13 representative retort pouch products. After consideration of the data obtained in this,

estimates were generated to establish shelf life values for the entirety of NASA’s retort

processed product stock. Finally, an overall assessment was made as to the suitability of these

products for use in extended duration missions.

Materials and Methods

Accelerated shelf life testing of representative products

Sample acquisition.

Thirteen retort processed pouched products were evaluated by accelerated shelf life

testing (ASLT).carefully chosen for evaluation, in order to be representative of a standard

spaceflight menu. A combination of menu items and proposed new products, were carefully

chosen for evaluation, depicted on table 1; all samples were processed with appropriate time

and temperature parameters to achieve commercial sterility.

Storage and sampling parameters.

Shelf life extrapolation was conducted via the standard ASLT procedure, which

included analytical quantification of quality, application of Arrhenius kinetics, and

mathematical prediction of shelf life for each food product (Labuza 1982; Perchonok 2002

30

Table 1–Food products evaluated by ASLT and their corresponding, designated categories.

An asterisk (∗) next to product name indicates that the products were developed for stability

assessment and were not standard menu items. Category Food Products

.

Instrumental quality analysis.

Instrumental evaluation of products proceeded at 4-mo intervals for the first 2 y of

evaluation, and at 6-mo intervals during the 3rd year. Specific analytical methods were

chosen in light of anticipated modes of deterioration for each product, in order to characterize

effectively quality loss through storage. Texture analyses were performed on aTAx-T2i

texture analyzer. Colour data were gathered on a Hunter Lab Scan XE colorimeter, Water

activity was measured with a Decagon CX-2benchtop water activity meter. pH was measured

on a standard bench top pH meter. ◦Brix was measured with a standard handheld

refractometer. All of these instrumental analyses were conducted in the Space Food Systems

Laboratory

Assessment of product nutritional quality.

Tests included a broad assessment of macronutrients, essential vitamins, and

minerals in products were submitted for baseline nutritional analysis within 3 wk of

production. Final evaluation was performed at shelf life endpoint, or after 36 mo of storage, if

shelf life exceeded 36 mo.

Analysis of product sensory quality.

Sensory evaluation of products proceeded at 4-mo intervals for the first 2 y of

evaluation, and at 6-mo intervals during the 3rd year. Panellists were maintained in isolation

31

for the duration of each test. Approximately 24 h prior to testing, samples were pulled from

each storage condition and allowed to equilibrate to room temperature (70 ± 2 ◦F). If

necessary, samples were heated in a 150 ◦F convection oven for 30 min prior to serving; all

other samples were served to panellists at ambient temperature (70 ± 2 ◦F).Within 2 wk of

receipt into the lab, food products were evaluated by quantitative affective testing for baseline

acceptability. These affective tests utilized a 9-point Hedonic scale .Attributes considered in

both acceptability and difference testing were product specific but generally included

assessments of appearance, texture, aroma, flavour, and aftertaste. Between 22 and 38

Panellists evaluated products at each baseline test point. Separate paired t-tests were

conducted to compare acceptability of the 2treatment samples and control samples (α = 0.10).

After baseline acceptability was determined, Difference-from control testing, based on

procedures outlined by Meilgaard and others (1999), was used to quantify differences

imparted to products over storage time. The specific Difference-from-control test employed

involved the presentation of 3 successive sample pairs to panellists, consisting of a control

(40 ◦F) sample paired with one of the treatment samples (72 ◦F, 95 ◦F) or blind control (40

◦F), and prompted them to assess the magnitude of the difference between several attributes

of the two. Panellists indicated their responses on a9-point verbal category scale that ranged

from “Extremely Different “to “Definitely the same. The mean Difference-from control score

was calculated for each sample and blind control. These data were evaluated by paired t-tests

to determine significance of the effects of storage temperature on each attribute (α

=0.10).After a significant difference from control was determined for any treatment, products

were evaluated at remaining test intervals by quantitative affective testing. The remaining

affective testing of products utilized the same questions as those used to determine baseline

acceptability. Affective testing continued until the average acceptability had declined to a 6.0,

or decreased by at least 20%,if original rating was initially less than 7.5. Separate paired t-

tests were conducted to compare acceptability of treatment samples and control samples (α =

0.10).

32

Shelf life extrapolation.

Shelf life endpoints (ts) at ambient temperature, which were not observed in the

36-mo testing period, were calculated by the following equation:

ts = t0e−aT, where ts = shelf life at 72 ◦F/22.2 ◦C, t0 = shelf at 95 ◦F/35 ◦C,

a = lnQ10/10, T = 12.8 ◦C.

Where analytical measurements did not reflect sensory assessments of quality, Q10 values

were obtained from the literature and used to predict shelf life value at ambient temperature

from observed sensory endpoints at 95 ◦F. This was the case for products whose main

mechanism of quality loss was defined in terms of flavour deterioration.

Estimation of shelf life for all retort processed pouch Products.

Estimates of shelf life values were made for all NASA standard menu retorted

products. This product information was reviewed to identify a maximum of 3representative

products (of the 13 evaluated by ASLT) that were comparable or similar to each menu item.

The average of the ASLT estimates for all comparable products identified was computed.

This average was accepted as the preliminary estimate of the shelf life for the menu item .To

compute a final estimate of the menu item’s shelf life, a list of differences expected to affect

longevity were noted between the menu item and the representative product(s). The

preliminary estimate of the shelf life for each menu item was then adjusted based on these

identified differences. These differences and their corresponding shelf life adjustments were

kept consistent and are summarized in Table 3.

33

Results and Discussion

Shelf life endpoints of representative products

Shelf life endpoints determined for the 13 representative products are summarized in

Table 4. Of these, 4 endpoint (SugarSnapPeas, Broccoli Soufflé, Vegetable Omelette, and

Rhubarb Applesauce) were observed during the 36 mo analysis; the shelf life values of the

remaining 9 items were determined by extrapolation.

Table 4: shelf life of food products evaluated by ASLT and principle mechanisms of quality

loss. Ranges have been given for those products whose shelf life end point was defined in

terms of a 20% quality loss, rather than by a minimum 6.0 quality rating

Baseline acceptability of representative products.

Baseline acceptability of sugar snaps peas

Bitterness and an unacceptable after taste as the reasons for the low acceptability

of Sugar Snap Peas after production. These off flavours were attributed to the increase in

organic acid content typically present in canned green vegetables (Lin and others 1970,

Clydesdale and others 1972). Incorporation of a preliminary blanching step and inclusion of a

brine packing solution are conventional means to avoid this off-flavour development.

34

Baseline acceptability of egg products.

Although retort processed egg products are not currently offered in the NASA

food system, 2 Candidate egg products were developed for consideration in this study. The

Broccoli Soufflé and Vegetable Omelette products were proposed .Texture was anticipated to

be an issue for these products, as the high heat applied the retort process would allow

extensive aggregation of egg proteins. In addition to texture, unacceptable appearance and

odour of egg products were cited by panellists as reasons for failure at 0 mo. The

unacceptable odour was likely due to formation of sulphurous gases produced during cooking

of eggs, and subsequent containment of that gas within the retort pouch. The observed,

greenish gray colour is likely due to the formation of ferrous sulphide that is often observed

with extended heating of liquid eggs at high temperatures (Gossett and Baker 1981). Odour

could be curbed by decreasing the egg product fraction of the formulation, and appearance

maybe improved either by acidifying the formulations with salts or through the addition of

various chelating agents. The phenomenon has been attributed to the denaturation of egg

albumin proteins with the continued application of heat, and reassembly into an extensive

fibre-like network. Although increased cohesiveness was not indicated by panellist comments

on the representative egg products studied, unacceptable hardness, springiness, and rubbery

quality were observed. Instrumental texture analysis of these products was carried out for the

duration of the storage analysis and showed that hardness of Broccoli Soufflé decreased

gradually over time (P <0.05).No such decline was observed for Vegetable Omelette,

presumably because of its higher protein content. Even with reformulation and in spite of

texture softening over time, retorted egg products are not likely to be acceptable for extended

duration missions. Emerging processing technologies (microwave/radio frequency and

pressure-assisted sterilization) should be considered for this purpose, as they appear to

provide acceptability and storage stability that are more appropriate to NASA’s needs

Quality loss to representative products throughout storage.

Overall, changes to the colour and flavour of representative products over time were

found to have the greatest impact on product quality. For the most part, these changes were

slowed significantly with product storage at low temperatures. Changes to product texture

and nutritive value during storage were also observed for several of the representative

products.

35

Colour loss in representative products.

Significant colour loss was generally limited to fruits, vegetables, and products

containing high proportions of dairy ingredients..Colour changes previously reported in long-

term storage of canned goods have been defined in terms of colour fading in green vegetable

products, high carotenoid products, and uncured meats; and colour darkening in bakery

products, starch products, fruits, and cured meats (Feaster 1949; Cecil and Woodruff 1963;

Goddard 1994). Although both fading and darkening were observed in the present study, the

latter was the most significant colour change influencing product quality. The most

substantial declines in colour were observed for fruit and vegetable products. On average, the

critical colour limits of fruit and vegetable products represented a decline of 20% in the value

of initial colour parameters .The most substantial fading of colour was observed in green

colour of Sugar Snap Peas, where the Hunter a-value had increased from 1.75to 2.92 after 20

mo of storage at 72 ◦F. However, decreases in the Hunter L-value during this time, indicating

darkening of the product, were found to have a greater effect on overall product quality.

Additionally, some colour fading was measured in the Grilled Pork Chop product, but was

not found to have a significant effect on the overall panellist acceptability over time. Colour

fading in Grilled Pork Chop was characterized in terms of a hue shift from orange to yellow-

green. This shift appeared to coincide with decreased reporting by panellists that the product

appeared red or pink over storage. The shift was not significant for the product stored at the

low temperature (40 ◦F) conditions. Although instrumental assessment showed gradual

change of all colour parameters over time for ambient and high temperature storage of these

products, panellist perception of colour change was limited to discernment of relative product

darkness. The lack of significance of colour fading in these products is likely due to their

formulations: Carrot Coins contains butter at 1.61% w/w; Apricot Cobbler contains pie crust

and sugar at 8.37% and 21.22%, respectively. Both of these products contain reasonable

levels of reactive browning precursors, which would therefore account for their darkening

over time. Cecil and Woodruff (1963) assessed storage stability of retorted Apricot Jam at 70

and 100 ◦F, and have noted similar product observations to those of the present study. Colour

changes in the Bread Pudding and Tuna Noodle Casserole products were characterized only

by product darkening. The critical limits of colour decline in these products were more

moderate than in fruits and vegetables However, although the colour changes were minor,

they were still reflected in panellist ratings of appearance for this product. This was likely due

to simultaneous progression of other quality changes that affect appearance, such as moisture

migration between sauce and noodle components. Rodriguez and others (2003) have reported

36

Similar findings in their analysis of retorted burrito combat rations. Specifically, their work

has suggested that extended storage of multi component pouched foods with high starch

contents has detrimental effects to the appearance, texture, and flavour of the food. The most

significant effects to these quality parameters in their retorted burrito products were found to

result from storage of the products at high temperatures. Similar characteristics were

observed for the darkening of Roasted Vegetables, but the colour aspects were overcome by

off-flavour development, presumably because of the relative mildness of the initial product

flavour.

Flavour changes in representative products.

Flavour loss was observed in terms of loss of characteristic product flavours and

formation of unacceptable flavour, with the latter contributing most significantly to overall

acceptability. For most products, flavour change was accompanied by a change in colour. For

those products found acceptable at baseline, flavour did not appear to drive overall sensory

acceptability until after a minimum of 16 mo of storage at ambient conditions .Panellist

acceptability of the flavour of all representative vegetable products (Carrot Coins, Three

Bean Salad, Roasted Vegetables, Sugar Snap Peas) was found to decline over time, especially

at ambient and high temperatures. Similarly, a decreased acceptability of aroma and

aftertastes were observed in vegetable products stored at high temperatures over time (P

<0.05). As these changes tended to coincide with product darkening, and because of the

nature of the products, flavour changes in these vegetable products were assumed to be

resultant from Millard browning reactions. Maillard reactions were also implicated in the

flavour and colour change observed in the Bread Pudding representative dessert product.

Association of colour and flavour changes has previously been observed in a canned fruit

cake product by Cecil and Woodruff (1963). Their research noted increasing perception of

“bitter” and “burned flavour” with darkening of colour. As these changes were accompanied

by hydrolysis of 50% of the product disaccharides, the study attributed them to non

enzymatic or Millard browning reactions. NASA dessert products are formulated with

adequate dairy, egg, and sugar ingredients to allow formation of characteristic flavours and

colours in dessert products by Millard reactions during processing. As most dessert products

are formulated similarly and are potentially subject to these reactions, they should

conceivably benefit from a moderate amount (<16 mo) of high temperature storage. The

extensive heat applied in retort processing typically results in an over processing of meat

products, to ensure sterility throughout the entire product (Potter and Hotchkiss 1998).

Perhaps with the implementation of non-thermal processing methods, off-flavour

37

development in these types of meat products could be avoided, and initial panellist

acceptance of the products might be improved. This could ultimately serve to increase the

shelf life of the meat entree products.

Texture changes in representative products.

Texture changes affecting quality of representative products in storage were limited

to moisture migration, starch gelatinization, and syneresis. These changes were most

considerable for those products with discrete components, and in products with high starch or

protein contents. Despite this perception of soft texture, panel list acceptance of initial

flavour, aroma, and other quality factors was satisfactory and allowed maintenance of product

quality throughout shelf life. Declines in flavour and aroma attributes, therefore, were

determined to be the primary mechanisms of quality loss for Home-style Potatoes. Schmidt

and Ahmed (1971) also reported decreased hardness of thermally processed potatoes relative

to unprocessed control samples after retorting. They attributed this difference to solubilisation

of intracellular pectic substances, absorption of water, and gelatinization of starch granules.

Prolonged storage of their processed potato samples indicated some hardness decrease due to

a reduction of starch granule water holding capacity over time. Another high starch product

considered in the present study was the Three Bean Salad vegetable product. Texture of this

product was found to be quite stable over time, but was greatly degraded by storage at low

temperatures. Storage at 40 ◦F was found to result in gelatinization of filling aid starches,

which shortened the shelf life of the product considerably to 12 m. With extended storage of

the retorted product, and especially with exposure to freeze thawcycling, cooked starches

within retort product filling solutions can be prone to retro gradation (Goddard 1994).

Replacement of the starch used in this formulation and avoidance of low temperature storage

of this product are proposed as countermeasures to realize the greatest shelf life for this

product. Changes to the textural quality of representative fruit products were reflected in

sensory ratings of each product’s texture, and were also presumed to have affected panellist

ratings of appearance. Both fruit products were noted by panellists to have lost firmness and

become thinner over time, with such effects being most pronounced at higher temperatures.

This was assumed to be the result of moisture release from fruit tissues and a subsequent

increase in free water in the products over time. However, no conclusive analytical data were

available to assess the rate of this deterioration. Texture data and free liquid measurements

were very inconsistent. This is likely due to the addition of varying levels of sauce to the

products, as sauce addition occurs as required to maintain acceptable pouch fill weights.

38

Shelf Life Estimations for All NASA Retort Pouched

Product

Shelf life estimations of NASA’s current stock of retorted products are

summarized in Figure 1. Fruit and dessert products were estimated to have a minimum shelf

life between 1.5 and 5 y; vegetable side dishes were estimated to have a minimum shelf life

between 1 and 4 y; soups and starch side dishes were estimated to have a shelf life between

1.75 and 4 y; and dairy products and vegetarian entrees are estimated to have a shelf life

39

between 2.5 and3.25 y. Meat products were found to be the most durable products, as they

were all estimated to maintain quality for a minimum of2 y, with an expected shelf life

maximum of 8 y. Of the 65 products, only 27 are estimated to have a shelf life of greater than

3 y, and would therefore fall within the minimum range required by AFT to support extended

duration spaceflight. Additionally, there are likely to be mission scenarios requiring up to a 5

y shelf life for food. Supporting such a scenario with the current food system would allow

only the provision of a limited number of entree products with shelf life estimates that extend

beyond 5 y.The bubble chart plots in Figure 2 are provided to represent the caloric and

nutrient provisions that would be possible in various mission scenarios, based on the shelf life

estimates of this study. Figure 2A represents a full landscape of foods in NASA’s thermo

stabilized product stock, with respect to each food’s caloric content and calculated nutrient

density parameter. The size of the bubbles in these charts is defined with respect to the

number of foods that exist in a given category. Calories are considered per100 g of the food

product. The nutrient density parameter for each food was defined internally, using NASA

requirements for food system nutrition (Smith 2005). The following 18 nutrients were

considered in the definition of this parameter: vitamins A, C, D, E, K, B1, B2, B3, B6, B12,

folate, biotin, pantothenic acid, calcium, magnesium, potassium, iron, and zinc. The level of

each nutrient that was present per 100 g of food was compared against the corresponding

NASA requirement, and points were awarded as follows: the presence of 10% to 49% of the

NASA RDI of a given nutrient contributed 1 unit to the nutrient density, the presence of 49%

to 99% of the NASA RDI of a given nutrient contributed 2 units to the nutrient density of the

food, and a nutrient present in excess of 100% of the NASA RDI contributed 4units to the

nutrient density. The sum of the nutrient density units awarded to each product per its

nutritional profile is represented in the nutrient density parameters plotted in menu landscapes

of Figure 2. While Figure 2A represents the menu landscape of the full product stock of

thermo stabilized foods, Figure 2B represents a menu landscape comprised of only the food

provisions that would-be possible with a 3-y shelf life requirement for NASA missions.

Furthermore, Figure 2C depicts the even more limited landscape of options that would be

available to support a 5-y shelf life requirement. As is apparent from the progression of the

charts in this figure, the menu landscape available to support a NASA mission becomes quite

limited with increasing requirements for the shelf life of the food system. In fact, supporting a

5-y scenario with the current food system would allow the provision of a very limited number

of meat entree products. Therefore, modification to the current food system will be required

to ensure provision of an adequate food system in extended duration mission scenarios.

40

Modification maybe accomplished in terms of individual product reformulations, application

of emerging non-thermal processing technologies, and development of low temperature

options for food stowage volumes. Reformulation of retorted pouch products should include

changes that will improve the initial acceptability of products, as well as those that may

improve product stability over time. Several means of reformulation have been proposed for

representative products herein. These should be considered on a product-specific basis as

appropriate for the entire stock of NASA’s retorted item. Additionally, Branagan and Pruskin

(1993) have reported that fortification of thermally stabilized cheese spread products can

allow the maintenance of adequate levels of several nutrients, even after exposure to adverse

storage conditions. Fortification of NASA’s retorted foods is likely to have a similar benefit

and should be considered to improve the nutrient value of the products after storage

.Incorporation of emerging and non-thermal preservation technologies are currently being

investigated by NASA through collaboration with the U.S. DoD. These are being considered

for their potential to improve the initial quality and as a means to extend the longevity of the

food system for use in extended duration spaceflight. Finally, as the present study dictates,

the most significant changes to the quality of NASA’s retorted products occurred at ambient

and high temperature storage conditions. Consequently, NASA should consider incorporating

low temperature storage volumes for support of extended duration missions, to further

prolong food system shelf life. These efforts would likely require significant integration

between the AFT program and relevant vehicle design teams. Provision of low temperature

storage volumes would allow shelf life for a majority of products to extend into the minimum

range defined by AFT.

41

Conclusion

Shelf life endpoints were established for all of NASA’s retorted pouch products. At

ambient storage conditions, shelf life endpoints of the products range from 0 to 96 mo,

depending on the product formulation. Therefore, use of these products to support extended

duration missions will not be feasible without modification. Modification may be

accomplished in terms of individual product reformulations, application of emerging non-

thermal processing technologies, and development of low temperature options for food

stowage volumes.

42

CASE STUDY-2

Development of freeze-dried miyeokguk, Korean seaweed soup, as

space food sterilized by irradiation

Beom-seok song. et al

Introduction

Seaweed has a long history as a food resource and popular food ingredient in Korea.

In particular, miyeok is often served in soup, salad, and side dishes. The Korea Atomic

Energy Research Institute has used irradiation technology to develop Korean traditional

foods, such as kimchi, as space foods.Irradiation technology has been considered as an

effective sterilization method to extend the shelf- life of space foods, without compromising

their nutritional proper- ties. Safety and taste of space food are important considerations for

astronauts; therefore, space food should meet rigid microbial specifications (Bourland, 1993).

The microbiological requirements for space foods used by the Russian Institute of Bio-

medical Problems (IBMP), which is a unique institute that certifies space foods for use on the

International Space Station, are shown in Table1. The sensory quality of space food is also

important to prevent malnutrition, because astronauts tend to avoid consuming unappetizing

food .The purpose of this study was to identify microorganisms in freeze-dried miyeokguk

and to sterilize freeze-dried miyeokguk using gamma irradiation in order to meet the IBMP

regulations pertaining to space food.

Materials

Dried miyeok and sea tangle were purchased from Chung-hoCo. (Busan,ROK).Other

ingredients were purchased from local markets.

Sample preparation

The preparation of freeze-dried miyeokguk is showing Fig. 1. Briefly, meat stock was

prepared by boiling 400g of beef, 20g of sea tangle, and 5gofgarlic in 3 L of water for 30

min. The meat stock was then stored for 24 h at 4 1C to remove the separated lipid layer from

the surface. After adding 2 g of dried miyeok and 1 g of salt to 25 mL of the meat stock, the

mixture was boiled for 10 min. The miyeok and aqueous soup were separated and freeze-

dried individually using a freeze drier. Finally, 2 g of freeze-dried miyeok and 2 g of soup

powder were mixed and packaged in an aluminium-laminated LDPE-polymer bag.

43

Gamma irradiation

Samples were irradiated in a cobalt-60 gamma irradiator at the Korea Atomic Energy

Research Institute. The source strength was approximately 320 kBq with a dose rate of 10

kGy/hr, and the actual doses were within 2% of the target dose. The absorbed doses were

measured using the alanine-EPR dosi- metry system

Microbiological evaluation and identification

A portion (10g) of the sample was aseptically placed into a sterilized bag with90mL of

sterile peptone water (0.1%) and homogenized in a stomacher blender for 2 minute. The

following medium were used for culturing :plate count agar for total aerobic bacteria ,SS agar

forSalmonellaspp.,MYPagarforBacilluscereus,3MPetrifilm(3MHealthCare,St.Paul,MNUSA)f

or Escherichia coli, Staphylococcus spp., and coli form bacteria ,potato dextrin agar for fungi.

A 1Ml aliquot was spread on to plates containing one of the above-mentioned media and

incubated for bacterial growth at 351°C for 48h and for fungal growthat25 1C for

5days,under aerobic conditions. Microbial populations from the sample cultured in triplicate

on each medium were evaluated by manually counting the colonies on each plate.

44

Colour measurement and sensory evaluation

Colour change in gamma-irradiated and rehydrated miyeokguk was measured

using a colour difference meter with the following standard colours: lightness (90.5), redness

(0.4), and yellowness (11.0).The sensory testing panel was composed of 10 trained panelists.

Each member evaluated the samples independently for its colour, flavour, taste, texture, and

over all acceptance using a7-point scale rangingfrom1(very bad)to7(very good).

45

Results and discussion

. Microbial evaluation and identification The evaluation of total aerobic bacteria ,

coli form bacteria, Staphylococcus, Salmonella, E. coli, B. cereus, and fungi in miyeokguk

and freeze-dried miyeokguk is performed. Colonies were not detected within the detection

limit of l.00 log CFU/g for any microbial species. To validate sterilization of the freeze-dried

miyeokguk, miyeokguk was rehydratedwith200mLofhotwaterat70˚C and was incubated at

35˚C for 48hr.Results are shown in Table 2. Total aerobic bacteria counts were 3.2 log

CFU/gat24h and 7.01 log CFU/g at 48h.These results suggest that heat treatment in the

preparation process was not sufficient to in activate all microorganisms in miyeokguk.

Species were tentatively identified as Bacillus cereus, B. subtilis, Enterobacter hormaechei,

and Acineto -bacter genom ,.B.cereus is widely distributed in several environments and is

known to cause food poisoning symptoms such as emesis and diarrhoea. Even if

microbiological regulations on space food permitted the presence of B. cereus below

10CFU/gin dried food products, the presence of B. cereus could be harmful to astronauts in

aerospace who have a lowered immune function .Therefore, sterilization of space food is

recommended in order to prevent food poisoning, because spore-forming bacteria such as B.

cereus can grow after rehydration and produce toxins. Sterilization by irradiation is an

effective method to inactivate microorganisms in dried food, because heat treatment of dried

food products can cause browning .Gamma irradiation of freeze-dried miyeokguk was

conducted to investigate the optimal dose for sterilization. Aerobic bacteria were not detected

in any sample just after gamma irradiation, and were also not detected in the incubated

samples irradiated at doses above 10 kGy.These results indicates that gamma irradiation of 10

kGy is enough to inactivate all microorganisms in the freeze- dried miyeokguk.

46

47

Conclusion

The result of this study indicate that gamma irradiation at 10 kGy could sterilize

freeze-dried miyeokguk without deterioration of the sensory quality of the food. In addition,

gamma irradiation at 10kGy was sufficient to fulfil microbiological requirements as space

food. Following this study, the microbiological and sensory qualities of freeze-dried and

irradiated miyeok- guk was further tested during a 51-day space environment simulation by

IBMP .Freeze-dried miyeokguk was certified by IBMP as space food usable in the Russian

segment of the International SpaceStationin2010.

48

CONCLUSION

There are many more lessons to be learned for the application of food technology to

space food without an adequate food system, it is impossible that space crew member’s

health and performance would be compromised. It is clear that in developing adequate NASA

food systems for future missions, a balance must be maintained between use of resources and

the safety, nutrition and acceptability of the food system. In short, the food must provide the

nutrients to sustain crew health and performance, must be safe even after cooking and

processing, must be formulated and packaged in such a way that the mass and volume are not

restrictive to mission viability. It is this delicate balance that frames the food system needs for

our next mission and charts the work for NASA ADVACED FOOD TECHNOLOGY.

49

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