English Tool Kit March 2011

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The Flour Millers Tool Kit on FortificationTable of Contents

Section 1: Introduction to Flour Fortification

Section 2: Procuring Materials & Setting up the Mill

Section 3: On the Production Line

Section 4: Assuring Quality Control

Section 5: Keys to Effective Marketing of Fortified Flour

Section 6: Cost Issues


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Section 1: Introduction to Flour Fortification

Reasons for Flour Fortification

Overview of the Fortification Process

Vitamins & Minerals Used in Flour Fortification

Impact of Flour Fortif ication on Public Health

Benefits to Mills from Fortifying Flour

Understanding Fortification Regulations

Ensuring Consumer Satisfaction of FortifiedProducts Section Summary


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Seven Reasons to Fortify Flour (Slide 1 of 2)

1. Fortifying commonly eaten foods, like wheat flour, is an effective andeconomical way to ensure that national populations are provided withessential v itamins and minerals.

2. These vitamins and minerals help prevent nutritional deficiencies such as

iron deficiency anemia, and some health problems and birth defects.

3. Flour an ideal medium for fortification, because it is a staple food. Morepeople can be reached by fort ifying the flour at the mill than by fortifying onlyflour products.

4. Fortification can significantly improve the health of a national population


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5. Fortifying flour can be beneficial for the national economy. Healthycitizens lead to increased productivity.

6. The World Bank estimates that vitamin and mineral deficiencies as a wholedepress GDP by as much as 5%. Fort ification of key staple foods withspecific vitamins and wil l help eliminate these deficiencies for as litt le as0.15% of GDP- the approximate fortification cost.

7. Flour millers can play a major part in solving these nutr itional problems byadding key vitamins and minerals. These nutrients produce a betterproduct, they can do so at low or no cost, and they help wholesalers bringbetter products to their customers.

Seven Reasons to Fortify Flour(Slide 2 of 2)


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Overview of Flour Fortification(Slide 1 of 4)

Fortif ication is the process of adding

vitamins and minerals to flour during themilling process, resulting in a higherquality, more nutritious product.

Vitamins and minerals are typicallyadded to flour during the milling processvia small amounts of a powdered premix.

More information about premixes is

found later in this toolkit.


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Prior to mil ling, whole grain wheatcontains signif icant levels of calories,

protein, carbohydrates and dietary fiber inaddit ion to many vitamins and minerals.Most of the vitamins and minerals are inthe bran and the germ of the wheat.

When flour is milled, the bran and thegerm are removed and discarded, leavingmostly pure, white endosperm. Thismeans that many of the vitamins andminerals are removed leaving, a productthat is less nutritious than whole grainwheat.



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The table shows the degree to which nutrients are reduced during milling. 100 grams/day ofwhole wheat flour supplies 22% of the United States Recommended Daily Allowance for iron.

Refined flour has less than one fourth of this amount (less than 6% of the RDA）



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Forti fication can restore to milled flour the natural levels of vitamins and mineralsfound in the wheat kernel or whole wheat flour. This process is commonly referred toas enrichment or restoration. It is one type of fort ification.

Fortif ication can also add vitamins and minerals in amounts higher than those naturallypresent in the whole wheat kernel. This type of fortification is very common and is usedwhere the populations consuming flour and flour products are deficient in one or moreof the vitamins and minerals added.

Another type of fortification used to help prevent deficiencies adds additional vitaminsand minerals that are not naturally present in wheat. Examples include vitamin A,calcium and vitamin B12.



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Vitamins & Minerals Used in Flour Fortification

Common minerals and vitamins added to flour Iron Zinc Folic Acid Other B vitamins (Thiamin, Riboflavin and Niacin) In some countries Vitamin A, Calcium and B12 are added.

How to decide on premix ingredients:

Generally, these decisions are made with the help of nutrition and researchorganizations that are involved in nutrition standards and problems of the population.

Decisions about which vitamins and minerals will be added to wheat flour depend ona number of factors

-- existing government regulations

-- dietary needs and deficiencies in the population-- the cost of different premix combinations-- results of research aimed at determining vitamin and mineral deficiencies

More information to help guide decision making on which vitamins and minerals

should be added to flour are found later in this tool kit.


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Impact of Flour Fortification on Public Health(Slide 1 of 3)

Fortification is a successSome countries, including the United States and Canada have successfully fortifiedflour with vitamins and minerals since the early 1940s. As a result, several vitamindeficiencies have been virtually eliminated in these countries.

The chart below shows reduced deaths from pellagra (niacin deficiency) in the United States sinceflour fortification began there.

0

500

1000

1500

2000

2500

3000

3500

1938 1940 1942 1944 1946 1948 1950 1952

Year

N u m

b e r o f d e a t h s


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Impact of fortif ied flour has been measured

The fortification process has a been tested again and again around the world, as

successful fortification programs have been implemented in many countries.

In the United States, folic acid fortification is estimated to have an annual economicbenefit of between $312 million and $425 million. The net reduction in direct costsare estimated to be between $88 million and $145 million per year.

In a Canadian study of 38,000 women aged 18 to 42 years, there was a significantimprovement in folate status after fortification with folic acid began. Folic acid, theform of folate used in fortification, helps reduce the incidence of neural tube birthdefects.



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15%

9%16%

37%

0%

10%

20%

30%

40%

Iron Deficiency Anemia

1992 1994

Through iron fortification of wheat and corn flours, Venezuela has lowered its rates

of iron deficiency and anemia.



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Benefits to Mills from Fortifying Flour

Flour fortification is an opportunity for mills to:

improve product quality by restoring vitaminsand minerals to original wheat levels and

improving its nutritional state

raise the company’s profile by helping createan image as innovative and on the cuttingedge of milling technology

expand market share and consumer brandloyalty through improved products

contribute to the health and productivity ofthe national population and receiverecognition as a good corporate citizen


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Explore national status and requirements

Mills owners and management start by learning the status of existingregulations related to fortification.

Mills owners and management can consult with the government authoritieson what is required and what is permitted regarding fortification.

General information on flour fortif ication regulations:

By July 2009, 57 countries had set flour fortification standards orcustomary fortification practices.

Regulations differ widely by country.

Some governments require mandatory fortification with certain vitaminsand minerals. Others allow fortification based on decisions by the millingcompanies.

A government may also decide to prohibit adding certain vitamins andminerals to flour.

Understanding Fortification Regulations(Slide 1 of 4)


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The map indicates countries that have fortification regulationsor are working toward implementing regulations.

Fortif ication Status – March 2011

Mandatory

Planning

Voluntary

No Flour Fortification


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Setting Standards

National flour fortification standards aremost often generated by technicalgroups.

They often include: government health specialists

standards specialists

nutritionists,

millers and often bakers and majorflour product manufacturers.

International donors may supportwork by such groups.

In a country without current standards orregulations on flour fortification, a mill

wanting to fortify flour needs to determinewhether flour fortification is allowed.

A special permit will need to obtained, orthe regulations will need to be changed, in

the very few countries that specificallyprohibit adding anything to flour.

Millers also need to learn about any

general fortification regulations whichapply to all foods. Such generalregulations for all industries fortifying foodproducts should also be observed by a millfortifying wheat flour.

For millers in countries without fortification regulation:



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Some regions where countries have similar basic food consumption practices haveestablished regional fortification guidelines as a basis for country specific regulations. Suchregulations facilitate inter-country active trade of wheat flour. Where the same premix isused nationally or in a region, procurement for mills may be easier and often at lower cost.

Regional fort ification guidelines



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Always include iron, folic acid and zinc in any wheat flour

or maize meal fortification program.

Addition of riboflavin is recommended.

Addition of thiamin in rice consuming countries and niacinin maize consuming countries is recommended.

Addition of other vitamins and minerals is optional.

Basic Recommendations for Flour Fortification


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Ensuring Consumer Satisfaction(slide 1 of 4)

In general, any good quality fortified wheat or wheat product should not changeconsumer acceptability of the fortified food. Ideally, fortification should be invisibleto the consumer.

If possible, there should be no detectable difference in the appearance, orsensory properties of the fortified product, and the price should only be marginallyhigher.

Characteristics to be control led to help ensure consumers acceptance andsatisfaction:

Color and Appearance

Flavor and Aroma

Shelf Life

Taste and Mouth feel

Sensory Testing


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Color and Appearance

The visual appearance of fortified flour and of foods products made from fortified flourmake a strong impression on the customer. Any change from unfortified flour should

be minimal. At the current fortification levels used in wheat, there is no adverse impact. Although

premix is generally a light yellow color, the very small amounts added cause littlechange in color of flour.

Elemental iron powders may cause a slight darkening of flour.

High levels of riboflavin and folic acid can cause a slight yellowing.

Experience has shown that these changes are accepted when consumers learn thatthe slight difference is caused by a vitamin or mineral once all flour is similarly treated

Premix Fortified flour



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Flavor and Aroma Like color and appearance, the flavor and aroma of fortified

flour should not be different from unfortified flour andproducts.

Shelf Life

Generally, the addition of vitamins and minerals to wheatflour should not reduce the normal or expected shelf life ofthe flour.

Any reduction in shelf life can result in lost products andreduced consumer acceptance of the food. Rancid productshave a slightly soapy mouth feel and a distinctive unpleasantodor.

Texture and Mouth feel

Product texture and mouth feel should be the same.

The premix ingredients decided upon should take expected shelf life into account.



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(China has successfully fortified flour for steam bread and home made noodles after initial testing.)


Sensory properties preserved

Extensive testing and experience prove thatfortification can be done without adversely affecting

the sensory properties in final products.These include:

Flour

Bread

Cakes Instant Noodles

Pasta

Unique products should be tested

Flour-based foods products unique to different regions of the world should be testedprior to starting a general fortification program to insure that products are acceptableto consumers.


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Section 1 – Summary

Compelling reasons to begin fortifying flour:

Fortifying flour can help improve the health of a national population by providingessential vitamins and minerals lacking in daily diets.

Flour fortification can be beneficial for the miller:

Helps to improve product quality

May increase market share and brand loyalty

Careful consideration of consumer’s expectations can be used so that consumersaccept fortified flour and it becomes part of their daily diet.

The many successful fortification programs implemented around the world offermodels on which to base new programs


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Summary of Fortification StrategiesThe general fortification strategies used in each country should be based on the public health

and economic situation. Usually a team of experts will determine which strategy is best.

Examples of strategies commonly used:

1. Restoration/Enrichment – The level of each nutrient in the unprocessed food must beknown if the criteria is based wholly or partially on restoring lost nutrients, which was theoriginal criteria for cereal enrichment in the United States and Canada.

2. Balancing dietary requirements – It is desirable to balance the levels of nutrients

contained in the fortified product and the dietary requirements. Folic acid is an exception tothis because higher levels are often added to prevent more neural tube birth defects.

3. Making up for dietary deficiencies – This strategy makes up all or part of the difference

between the dietary requirement for a nutrient and its average consumption by the general ortarget population. This calculation depends on which dietary requirement values are used. Itcan also be difficult to find good data on nutrient intakes for some target populations.


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Summary of Millers’ Role in Standards

The process of establishing standards and associated regulations is complex andtime consuming. It should always involve representatives from the medicalcommunity, the milling and baking industry and the government (usually throughthe ministry of health and government standards organizations). Others involvedmay include consumer groups, educational/research institutions, interested NGOs

and international and bilateral specialists.

An alliance of these groups needs to assess what is needed and what is feasible.To assure acceptance of the fortified products and compliance with regulations,major stakeholder groups must agree to the final regulations.

Cost is always a major factor in decisions about standards. Cost often restricts thetypes and levels of vitamins and minerals to include. High costs make it verydifficult to require vitamin A and calcium. Costs also makes it more practical to add

a premix of other minerals and vitamins that are needed by the population, becausetheir addition to the premix involves very low additional costs.


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End of Section One

Continue

Return to Table of Contents

Go to first slide of this Section

Section 2A

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Section 2A

Procuring Materials and Setting Up the Mill

Issues to Consider

Choosing a MicronutrientPremix

Choosing an AdditionMethod

WHEAT


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Issues to Consider

Choose high quality wheat:

Nothing added during vitamin and

mineral fortification will improve themixing and baking performance of poorquality wheat.

If low quality wheat is fortified, consumers

will likely blame the poor quality of thefortified flour on the added vitamins andminerals. This bad first impression maylead them to reject all fortified flour.


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Phytic acid that is naturally in grains inhibits the absorption of iron, zincand other minerals by the human body.

Whole grain wheat contains nearly 1% phytic acid. Milling removes phyticacid in flour by 60% to 90% depending on the extraction rate. These lower

levels improve the absorption of minerals.

As a general rule, the lower the level of ash in the flour, the lower the phyticacid content.

When yeast is combined with f lour in bread making, it further lowers the level

of phytic acid.

Vitamins and minerals are absorbed best f rom white refined wheat flour withan ash content of below 0.80%. Higher extraction rates of flour can andshould be fortified if consumers prefer higher extraction f lours.

To counteract the effect of phytic acid and maximize the benefits offort ification, flours of di fferent extraction rates need to be fortified withdifferent forms and amounts of premix fort ificants.

Issues to Consider


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Phytic Acid’s Effect on Mineral Absorption(slide 1 of 4)

Whole cereal grains contain phytic acid,which forms insoluble compounds withminerals, particularly calcium, iron and

zinc. These compounds are diff icult toabsorb in the body.

Much of the phytic acid is located inthe outer layer of the wheat betweenthe endosperm and the bran. Much of

the phytic acid is removed in themilling process, so highly refined whiteflour contains lower levels of phyticacid compared to high extraction wholewheat flours.

OPO3H2

OPO3H2

OPO3H2

H2O3PO

H2O3PO

H2O

3PO

H

HH

H

HH


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Yeast and flour provide the enzymephytase which destroys most of thephytic acid during dough fermentation

in the bread making process. Morethan 70% of the phytic acid can behydrolyzed; the longer thefermentation and the lower the pH,the more phytic acid is removed.

Phytic acid therefore is of mostconcern when high extraction flour isused to make unleavened bread, or in

non-fermented flour products likenoodles. This, however, is a commonuse of wheat in many countries of theworld.


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If the molar ratio of phytic acid to iron is less than 6 for normalpopulations, iron will be absorbed. This is the case for yeastleavened bread made from white flour.

If greater than 6 for normal populations, iron will not be wellabsorbed. This may be the case for noodles made from white(low extraction) flour.

An ideal ratio of less than 1 ensures absorption by anypopulation. This will not be possible for non-fermented flour

products like chapattis, noodles and steamed bread. You can lower the ratio by

Increasing iron (through fortification) but you can only add somuch iron.

Lowering phytic acid (through milling, fermentation or addingthe enzyme phytase).



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Two compounds prevent phytic acid frominhibiting iron absorption:

ascorbic acid (vitamin C)

sodium EDTA

Unfortunately, ascorbic acid is destroyed inmost baking processes. It is also expensive

to add.Sodium EDTA, however, is not destroyed.



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The Addition of Ascorbic Acid

Adding ascorbic acid to enhance iron absorption from fortified food isa widely-used practice for processed foods, but not for wheat flourdue to stability issues.

The main difficulties with adding ascorbic acid as a food fortificant arethat substantial amounts can be lost during storage and preparation,and compared to other nutrients, it is relatively expensive.

When ascorbic acid is used to enhance iron absorption, it should beadded in a 6:1 ascorbic acid:iron weight ratio. A higher ascorbicacid:iron ratio of 12:1 can be recommended for foods with high levelsof phytic acid. In most studies, the 6:1 ratio increased iron absorption2 to 3 fold in adults and children.

NOTE: Many millers add ascorbic acid as a bread improving agent.Unfortunately, it must be oxidized in the dough to the dehydroscorbic

acid form for it to function in that manner, but that form does not

provide iron absorption enhancement activity.


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The Addition of Sodium EDTA

Sodium EDTA is stable during processing and storage. It works bychelating iron at the low pH levels of the stomach to prevent it frombinding to phythic acid. It enhances the absorption of both food iron

and soluble iron fortificants, but not the relatively insoluble ironcompounds such as ferrous fumarate, ferric pyrophosphate orelemental (reduced) iron.

A Na2EDTA:iron weight ratio of 3.3:1 to 6.6:1 is recommended forfoods fortified with soluble iron compounds such as ferrous sulfate toincrease the absorption 2 to 3 fold.


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The World Health Organization recommends the following types and amounts of iron in

premix based on different extraction rates for low extraction flour (ash content <0.8%):

Use small particle size dried ferrous sulfate or small particle size ferrous fumarate.

In populations consuming more than 300 g/day of wheat flour products, add 20 ppmiron from dried ferrous sulfate or fumarate.

In populations consuming 150-300 g/day of wheat flour products, add 30 ppm iron fromferrous sulfate or ferrous fumarate.

In populations consuming less than 149 g/day of wheat flour products, add 60 ppm ironfrom ferrous sulfate or ferrous fumarate.

If cost or other factors (such as storing fortified flour longer than three months) make itimpossible to fortify flour with either ferrous sulfate or fumarate at the levels above, use

electrolytic iron or other iron fortificants with a relative biologic value of at least 50% ofdried ferrous sulfate. The level of these iron sources added to flour should be 2 timesthat of ferrous sulfate.

Sodium iron EDTA (NaFeEDTA) at levels up to 40 ppm is recommended for low

extraction flours where there is no fermentation process in food preparation (i.e. in thepreparation of unleavened breads such as chapatti or noodles).

Issues to Consider


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The World Health Organization only recommends sodium iron EDTA for highextraction flour (ash content > 0.8%). The recommended rate is:

In populations consuming more than 300 g/day of wheat flour products, add15 ppm NaFeEDTA.

In populations consuming 150-300 g/day of wheat flour products, add 20ppm NaFeEDTA.

In populations consuming less than 149 g/day of wheat flour products, add

40 ppm NaFeEDTA.NaFeEDTA should also be used in populations where the overall diet is of lowiron bioavailability. In these environments, the addition of up to 30ppm of ironfrom NaFeEDTA is recommended as long as there are no adverse effects on theflour’s sensory properties.

Issues to Consider


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Choosing a Micronutrient Premix

Premix Components

Advantages of Using a Commercial Premix

Determination of the Premix Formula

Procuring Premix

Choosing a Reliable Premix Supplier

Shelf Life of the Bulk Premix

Considerations When Using Other Flour Addit ives

Addition Rates and Overages

Recommendations

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Premix Components

The most common flour fortification practice is to add multiple vitamins andminerals using a single ingredient- called a premix.

Premixes are produced by large commercial manufacturers and can be purchasedin specific blends that meet the production needs of the mill and the dietary needsof the country.

A premix is made up of two major elements: Fortificants (powdered vitamins and minerals)

Excipients (carriers, fillers and free-flow agents)


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Small amounts of concentrated vitamins and minerals individually are hardto add to flour because they are excessively light or dense, tend to clump,and are difficult to feed in the small amounts required. A larger amount ofdiluted premix is easier to feed and to obtain uniform distribution in thefortified flour.

An excipient such as starch or maltodextrin is often blended into the

premix by the manufacturer to dilute the concentration of the vitamins andminerals. Excipients may be referred to as carriers or fillers by premixmanufacturers. After an excipient is added, the bulk density of the premix islowered, bringing it closer to the bulk density of the flour. This makes foreasier feeding and blending.

In addition to excipients, a free-flow agent, such as tricalcium phosphate orprecipitated silica (silicon dioxide) may be added to keep the premix fromclumping and bridging in the hopper.

Premix Components


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Generally, it is NOT recommended for millers to orderconcentrations of vitamins or minerals individually and add themone at a time or blend them at the mill. The one exception iscalcium, which is normally added separately due to the large

amount required.

Few mills are sufficiently equipped to undertake the complex taskof blending their own high quality premix, which requires difficultingredient procurement and extensive quality control testing.

The major advantages to using a commercial premix are:

1. Easier Feeding:

Some of the vitamins and minerals are very dense, (reduced iron)while others are very light (riboflavin). The proper use ofexcipients by commercial premix manufacturers mixes them intoa single ingredient that is much easier to feed and will causefewer problems on the flour mill’s production line.


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2. Easier Quality Control Testing:

A properly manufactured premix has verified levels of different vitamins andminerals that will allow testing of a single micronutrient to serve as an

indicator for the amounts of the others. Most often, iron is used as theindicator nutrient (but others could be used as well). If a mill blended itsown premix, it would need to prove that the blend met requiredspecifications. Very few mills have the lab facilities or staff needed to carryout such quality control procedures. It is much easier and less expensive

for the premix manufacturers to carry out this task. See Section 4 for moreinformation quality control testing.

3. Feed Rate Adjustments/Weighing:

A single premix requires only one feed rate adjustment for continuous flowsystems or one weighing for batch systems. This reduces laborrequirements and lessens the chance of error. See Section 3 for moreinformation on feed rates.



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Determination of a Correct Premix Formula

As noted in Section 1, determining which vitamins and minerals will be addedand in what amounts for fortified flour in a country is a complex process thatmay require the expertise of health specialists, nutritionists, millers, bakers and

food manufacturers, international donors and the national government.

In most countries, the government has the final say about the fortificationstandards. However, the premix’s specific composition is not normallyregulated. Usually, it is determined by the experience of the premix

manufacturer and the needs of the miller to ensure that the flour producedmeets a regulated minimum standard set by the government.

Premix manufacturers have extensive experience calculating premix formulasand can work with each mill to provide the proper premix for that mill.


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The following factors are considered by the premix manufacturers whendetermining a premix formula:

1) Nutrient concentration of the different forms of fortificants:

Some vitamins and minerals are available in multiple forms, and theconcentration of vitamins and minerals varies among these differentforms. This variation must be accounted for in determining how much ofeach nutrient to add.

2) Premix addition rate and bulk density:

The bulk density of the premix will affect the addition rate and vice versa.Both of these factors need to be considered together.

3) Overages:

Commercial premixes may have extra amounts of fortificants to controlfor losses in nutrients throughout the fortification process.

Determination of a Correct Premix Formula


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Pre-blends:Preparation of Diluted Premix

Ideally, the feeder should be set to operate between 20 and 80% of fullcapacity. In some cases mills may find that the flow of flour to be fortifiedis so slow as to require operation less than 20%, even when using all the

adjustments available in screw size and gears available. In that case themill may want to consider making a dilution of the premix.

A diluted premix, called a pre-blend, may also be needed if the premix is

not feeding uniformly or properly for some reason.

To make a pre-blend, use a batch mixer to mix flour or semolina(granulated flour) with the premix. An example would be 1 part premix

and 4 parts semolina. The resultant pre-blend would then be used at 5times the addition rate of the original premix (or 1000 grams/MT if thepremix was specified at 200 g/MT).

Pre-blends have a limited shelf life of only a couple weeks, so the amountproduced or delivered to a mill should not exceed a two week supply.


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The addition rate of the premix is needed to determine the final formulationof the premix. Ideally, the addition rate is set to be in whole units, andtypically added at a rate between 50 and 300 grams per metric ton of flour.

Rates lower than this may be too difficult to control accurately.

Small mills may require a more diluted premix that can be added at rateshigher than 300 g/MT. In that case the mill may mix the premix with flour

to create a pre-blend that is more dilute and that can be added at higheraddition rates.


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Some added vitamins and minerals may be lost during milling due to exposure to heat,

oxygen and light. Some very light or small particle size materials with large surface areamay be physically removed with the dust during pneumatic suction. Larger particles maybe removed during sieving. Such milling losses need to be factored in when calculatinghow much of each nutrient to include in the premix to meet a minimum standard in thefinal product.

Manufacturing Overage

Premix manufacturers usually include individual premix fortificants at levelsapproximately 2% to 5% higher than listed on the lable to ensure that the

premix meets the label claims.Mill Overage

Millers usually add extra amounts of the premix or individual nutrients to theflour to ensure that the final fortified flour meets the label claims. This is done

to account for variation in the natural level of vitamins and minerals in theflour and it makes up for any processing or storage losses.

As an example, to fortify wheat flour, that naturally contains 12 ppm iron tothe U.S. standard of 44 ppm, 35 ppm iron is typically added, (This is the

target level minus the natural level plus 10.)



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How to Procure Premix

Normally, mills purchase premix from one supplier who provides all the premix for a setamount of time.

The Mill Purchasing Department should keep the following information about the

supplier on fi le:

The name and address of the supplier’s company or organization.

The name and phone number of the principal contact to whom the order should bedirected.

The name or type of the premix to order

The standard amount of the premix that is ordered

The price history of the premix

The method and time of delivery

Mill staff should meet with the suppliers’ agent at least once per year to review

premix performance with respect to timeliness of delivery, quality, and price.

Sufficient stocks of premixes should always be maintained. Therefore, premixes shouldbe purchased well in advance of their running out. A reordering point in inventorylevels should be specified in the mills quality assurance plan to trigger the purchase

order, but production schedules should also be regularly consulted.


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Some countries have companies which manufacture premix, but in other cases, it needs tobe imported.

Smaller mills may find it more convenient and less costly to obtain premix through acentralized, cooperative purchasing group, either through a local millers association, aprivate enterprise or a government run operation. It may be possible for these groups to

obtain competitive bids from approved suppliers for a specified premix through an internetbidding system being set up by GAIN known as the Premix Facility. GAIN is the Global Alliance for Improved Nutrition.

The reliability of premix suppliers remains an issue of concern that many organizations areworking to address. Organizations such as the Micronutrient Initiative of Canada

(http://www.micronutrient.org) maintain lists of premix manufacturers.

Some countries, such as South Africa, have gone as far as to create approved lists ofpremix-suppliers that must be used. See http://www.grainmilling.org.za/ - click VitaminSuppliers.

Please note that no specific supplier is specifically endorsed by this toolkit, and allpotential suppliers should be thoroughly investigated prior to purchasing premix.

How to Procure Premix

http://www.micronutrient.org/http://www.grainmilling.org.za/http://www.grainmilling.org.za/http://www.micronutrient.org/


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To ensure that the received premix is correct and of good quality, the mill purchasingor receiving department should be responsible for inspecting premix upon delivery. Apremix receiving procedure including the steps listed below should be implementedto ensure thoroughness:

1. Check the boxes for any damage and record if there is some. Mild damage tothe cardboard box is acceptable, but severe water damage and tears in the innerbag are not.

2. Record date received and who is recording this data.

3. Record type or name of product and number of boxes or total weight and checkagainst what was ordered.

4. Record the lot numbers.

5. Check for a certificate of analysis (CoA) and put it in the fortification file. Thismay be on one of the boxes or sent separately (fax or email).

Record all of this information on a “Premix Receiving Report”

Premix Receiving Procedures(slide 1 of 5)


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Premix Receiving Procedures(slide 2 of 5)

Check the contents of one box of each lotreceived to see if the appearance is

normal. The premix should be free flowingwith no lumps, white spots or specs, andno off-odor. Run a gloved hand throughthe premix to check this. The operator will

do the same thing when he uses it, but bythen it may be too late to register acomplaint if something is wrong.


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A label should be firmly affixed to every box.

The label should show:

a) The name of the productb) The intended use of the product

c) The manufacturer with contact information

d) Handling precautions, if any

e) The date of manufacturer or “use by” date. (This is sometimes imbedded inthe lot number)

f) The lot number

g) The recommended application rate

h) The net weight

i) A list of ingredients.

Premix Suppliers Should Provide:(slide 3 of 5)


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A Certificate of Analyses (CoA) on each lot of premix for all nutrients in thepremix

The CoA (sometimes referred to as a “ Certificate of Quality” ) is the official

documentation of premix quality. This certificate should be provided for eachlot of premix in the shipment. The CoAs for all premix batches received shouldbe kept on fi le and made available for any inspections that may be required.

The CoA should indicate:

Chemical assay of the premix batch for each nutrient contained(except for vitamin B12 if present, whose level can be verified byaudit rather than actual assay). It may indicate the minimum andmaximum assay standards for that premix as reference.

Batch or lot number

Date of manufacture or expiration date or “ use by” date if notimbedded in the lot number


P i S li Sh ld P id


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A Product Information Sheet or Fact Sheet

This document should be kept on fi le at the mill and made available to all operatingand quality control personnel.

Information provided in this document should include:• The name of the premix• The name and contact information of the manufacturer • The intended use of the premix• The ingredient composition of the premix – usually in descending order

• The food grade status of the ingredients used, (i.e. Food Chemicals Codex (FCC)grade)• The recommended addition rate of the premix to flour and the levels ofmicronutrients added at that rate• The minimum assay standards for the premix, and maximum assay standards if any

exist• Storage and handling instructions• Allowable storage periods or shelf life of premix

Sh lf Lif f h B lk P i


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Shelf Life of the Bulk Premix

Vitamins in the fortificant premix have a limited shelf life. Over time theirbiological effectiveness is reduced. Most premixes not containing vitamin Aor C will last up to three years if stored properly. Minerals are particularlystable and the vitamin shelf life usually determines the shelf life of thepremix overall. Premix manufacturers should always provide shelf lifeinformation for their specific premixes. Millers should not expect premixmanufacturers or distributors to accept return of premix that has exceededits shelf life period.

Vitamin A is the only fortificant normally added to flour that is veryperishable. Premixes containing vitamin A may have a shelf life of as littleas 6 months.

These shelf-life specifications were taken from information provided from

premix manufacturers, but shelf life may be further reduced if premix isstored incorrectly at the mill.

Mill St f P i


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Mill Storage of Premix

Premix boxes should be keptsomewhere in the mill that is handybut not exposed to sunlight, notexcessively hot (i.e. next to a boiler)and safe from getting wet or hit by lift

trucks. The boxes can be piled on topof each other, but it should be soarranged that a first-in, first out systemof use could be easily accomplished.

One or two working boxes of premixcan be kept near the feeders, asshown in the picture.

Note additional information on safehandling of premix later in this tool kit.

C id ti Wh U i Oth Fl Additi


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Considerations When Using Other Flour Additives

Some flour mills add small amounts of bleaching agents and improvers to flour,such as enzymes and oxidants. Azodicarbonamide, benzoyl peroxide, potassiumbromate and ascorbic acid are commonly added oxidants.

Even though it might be tempting to add improvers and fortificants with the same

feeder, this is NOT recommended, for the following reasons:

1. Improver addition rates need to be adjusted frequently to ensure that differentflours all meet commercial specifications.

• Combining improvers and fortificants makes changing the addition rate of theimprovers more diff icult .

2. There are also safety reasons for avoiding combining improvers and fortificants.

• Some forti ficants can react with improvers. For example, concentrated formsof potassium bromate and benzoyl peroxide (“ flour bleach” ) should NEVERbe combined with forti ficants because there is a danger of combustion.

• The shelf li fe of vitamins might be altered if combined with improvers.

C id ti Wh U i Oth Fl Additi


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It is helpful to segregate boxes of premix and improvers. This could be donewith color coding or clear labeling.

The container storing the premix as well as the feeder being used to add a

particular premix or improver should be well identified to prevent accidentalreplacement with any other flour additive or premix.

When multiple feeders are installed in a row, it is referred to as a feeder bank.These photos show various sizes of feeder banks.

(Photos courtesy of Research Products Company)

Considerations When Using Other Flour Additives


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End of Section 2A

Continue

Return to Table of Contents


Section 2B


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Section 2B

Choosing an Addition Method

Mill Requirements for Proper Fortification

Methods Used to Add Premix to the Flour

Information on Premix FeedersConsiderations Regarding the Size of the Mill

Types of Delivery Mechanisms

Ensuring Adequate Mixing

Equipment Suppliers

Lessons Learned from Other Millers

Information on Specific Nutrients Added

Mill R i t f P F tifi ti


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1. A premix feeder to measure out thecorrect dose of premix and its placement at

a point in the production line where itdelivers the premix into the production lineto mix with flour.

Sometimes a small shoot or tube isfabricated and installed to carry the premix

from the feeder to flour line. This should

be at a steep angle to insure it drops down

cleanly without stoppage.



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2. Mechanisms to assure that the premix is uniformly mixed into the flourafter the point of addition and before packout. This can involve mixingduring the normal transport of flour from the conveyor to packout, or

insertion of special mixing equipment.

Packout

addition of premixat flour collectionconveyor




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Once the premix formula is determined, the best method toadd the premix to the flour needs to be selected.

There are two main delivery systems:

- Batch

- Continuous

There are different requirements for each method.



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Batch Systems:

The premix is measured out and is put into abatch of flour and blended with a mixingdevice. Fortifying within a batch system canbe slower and more labor intensive thanother methods, but it can be very accuratewhen a precise scale is used and can bemade automated.

(Photo courtesy of Buhler Company)


Batch Systems


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Batch Systems

In-line batch mixers

Some mills have batch mixers as part of theirnormal milling process (such as that shown in thepicture to the right). This is to blend flours or add

vital wheat gluten. A fortification premix can be added to these

mixers, either manually or automatically usingstandard microfeeders.

Separate mixers

It is possible to use a separate mixer to fortifyflour, but it is very inconvenient to do so and only

small batches of flour can be processed, so it isnot recommended except for very small millswhere continuous fortification is not feasible.



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Continuous Systems:

Most larger and newer mills operate within a

continuous system. The premix is continuouslymetered or fed into the flour flow using a precisionmicro feeder , also referred to as a dosifier . Thedosage rate is controlled and depends on the rate offlour production of flour flow.

The continuous system incorporates a collectionconveyor (shown on right) where premix can becontinuously and easily added. The majority of theinformation presented here refers to such milling

systems.


Feeders


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Feeders

To prevent premix from bridging inthe hopper, a large conditioningscrew, flexible pulsating plates on

the bottom of the hopper, or avibration device may be installed inthe hopper.

A low-level detector may beinstalled on the bottom of thehopper to indicate when the premixis close to running out.

The outlet spout of the feedershould be covered but afford easy

access to inspection and checkweighting.

Information on Premix Feeders

Feeders


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Feeders should be set up with anelectrical interlock system thatprevents the flow of premix whenflour flow is stopped.

The on/off switch, speedcontroller, and low- level indicatorlight can be located near thefeeder or at a remote location.

Some installations may need avoltage regulator to ensureproper performance of the feeder

and controller.

Feeder

Controller

Feeders

Electrical Interlock System


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An interlock causes the feeder to stop if the flour collection conveyorstops. This will prevent the inadvertent over-treatment of the flour, ifthere is a mechanical breakdown in the mill.

It is highly recommended that an electrical interlock system beinstalled between the feeder motor and the motor driving the flourcollection conveyor.

In pneumatic delivery systems, an interlock should be madebetween the feeder and the blower to insure that the feeder cannotbe turned on without the blower operating. This will prevent buildupof the premix in the pneumatic lines followed by over-treatment of

flour once the blower is turned on.

An alternative approach is to have an automatic shut off switch onthe feeder that is hooked up to a flour flow indicator or a pressure

indicator in a pneumatic system.



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The most accurate method of flourfortification is to continuouslyinterlock the addition rate of thefeeder with the measured flow rate

of the flour.

This requires equipment formeasuring the flow rate of the flour

and computerized mill controlallowing the interlock.

Interlocking (slaving) premix addition to f lour flow:

Feeders


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Premix Feeder Mechanisms

Three main types of premix feeders are available to fortify flour. Theydiffer in terms of the mechanism used to deliver a constant rate of premixpowder. There are also differences in cost. See Section 6 for more

information about the cost of feeders.

Type one

Screw Feeder

Type two

Revolving DiskType three:

Drum / Roller

Feeders

Mechanical Principles of Feeders


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Gravimetric Addition:

One general principle by which feeders control the amount of premix added to flour isgravimetric addition.

Gravimetric addition involves measuring the weight of material to be added on acontinuous basis. Weigh belt feeders are used in continuous systems that can givedirect weighings of the material being dispensed, but they usually require a greatervolume of material than used in most fortification operations.

All three types of feeders can be made into “loss in weight” feeders by mounting themon load cells that send out an electronic signal proportional to the total weight. Therate at which this weight drops with time indicates the true addition rate.

This system is somewhat more complex and expensive than is required in most cerealmilling operations, but it allows greater accuracy of addition and continuous traceabilityon the amount of premix used.



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Volumetric Addit ion:

A second general principle by which feeders control the amount of premix added to flouris volumetric addition (most commonly used via screw feeders):

Volumetric addition is similar to using a cup or spoon to measure out ingredients. This isbased on the principle that the volume of the material being added has a set weightwhen handled in a uniform manner. The minimum error of measurement for volumetricaddition is ± 2%.


Screw Feeders


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Volumetric screw feeders that dispense aset volume of a premix at a constant rateare the most commonly used machines tofort ify flour at the mill . They are poweredby a variable speed direct current motorwith a controller that is used for fineadjustment of the feed rate of the powder.

The size of the feed screw determines thefeed rate capacity. Large capacityfeeders may also use a gearbox to

increase and adjust the feed rate capacity.

Screw Feeders

Screw Feeders


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Advantages of screw feeders:

Better able to sustain a constant addition rate for alonger time

Wider range of delivery rates

Fewer mechanical parts

Fewer repairs because they breaks down lessoften

Less expensive to build

Can be more sanitary Easier to maintain than the other types of feeders

Widely available because screw feeders are nowthe most common type of microfeeders and areproduced by a larger number of manufacturers.

Photo courtesy of Buhler Company

Screw Feeders

Revolving Disk Feeder


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Revolving Disk Feeder

This is an older type of volumetric feeder that uses a revolving disk equipped with a slidemechanism to control the rate of powder discharge. The disk revolves at a constant speedpowered by either an AC or DC motor. The hopper size is usually smaller than in other typesof feeders, and must therefore be refilled more frequently. This can be a disadvantage forlarger flour mills. This type of feeder also has more mechanical components than the screw

feeder.

Drum or Roll Type Feeders


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Drum or rol l-type feeders have been used for decades and many thousands are still in

use. They can be set up as volumetric, gravimetric or loss of weight feeders. Theyoperate by allowing the premix powder to pass between two closely set revolvingcylinders.




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Either a DC or AC motor can power the drum and a gearbox. A pulley systemcontrols the rotation speed. Pulleys and wheels of differing diameters makegross adjustments in the feed rate. An adjustable gate is used to make fineadjustments.

Drum or roll-type feeders require more parts to operate and higher maintenance.Shear pins in the drive mechanism break if large objects (bolts, plastic) getstuck between the rolls, and the feeder will stop working until a new pin isinstalled.

In some newer drum feeder models, a variable speed DC drive motor is used toallow the addit ion rate to be adjusted electronically rather than mechanically.Variable speed AC drive motors are also available.


Sizing Feeders to the Capacity of the Mill


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Sizing Feeders to the Capacity of the Mill

Mills generally need one feeder per flour or meal line to be fortified. Larger millingunits with multiple products may require additional feeders including spares.

Feeders used for flour fortification need to deliver only relatively small amounts ofmaterial. The size and number of feeders needed will depend on the hourly

throughput of flour in the mill or load-out system. Hopper size on the feeder is also animportant consideration, since you do not want to fill it constantly, nor do you want tolet it go for many days without filling.

Photos courtesy of Research Products Company

Feeder Sizing


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Feeder Sizing

Powder premix feeders are available indifferent sizes.

A small feeder may discharge premixat levels as low as 25 g per hour (0.4

g/min) The largest can discharge up to 32

kg per hour. This would only beneeded with calcium fortification.

Volumetric feeder and hopper capacityare normally given in Liters/min and Liters.This can be converted to weight units byknowing the bulk density of the premix (ing/cc).

MillCapacity

(MT/day)

Flour flowrate*

(kg/min)

Premix**

Add rate

(g/min)

5 2.5 0.4

20 10 1.5

50 25 3.8

100 50 7.5

200 100 15

400 200 30

* At 72% extract ion rate** At 150 g/MT

Delivery Mechanisms


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Delivery Mechanisms

There are two main ways to deliver the premix to the flour:

pneumatic

gravity feed

Pneumatic System


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Pneumatic System

In a pneumatic system, the premix drops into a venturi tube, that injectsthe premix into an air stream. The material is blown by positive pressureor sucked by a vacuum through a pipe into the flour collection conveyor.

If this can not be set up, some downstream location in the flour flow can

be used to add premix provided it will be well mixed with the flour.

venturi tube

Pneumatic System


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Advantages of the pneumatic method

The feeder can be located at several places in the mill,allowing it to be added to existing mills.

Things to Consider:

Pneumatically conveyed flour does not provide muchmixing with the premix. Premix should be blown inbefore flour reaches a mixing (collection) conveyor orsieve rather than directly into a flour holding bin.

Pneumatic addition requires some investment on

additional equipment such as blowers, valves and piping. The pipes used to convey the material should have a

minimum number of sharp bends and twists to preventthe possibility of blocking pipes and clumping by theflour fortificant.

The venturi tube should be checked occasionally to seeif there is any build up of the premix, and cleaned whennecessary.

Pneumatic System

Venturi Tubes


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e u ubes

A venturi tube is a simple piece of equipment that connects thepremix feeder and the pneumatic delivery pipes. Venturi tubes areused to deliver the premix into the flour stream in an entirely closedpneumatic system.

Venturi tube arrangement


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gat discharge from feeder

Gravity Feed System


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With this system, the feeder is placed above a flour conveyor. The premixis dropped directly into the flour as it flows through the conveyor. Mostoften the feeder is placed above or near the flour collection conveyor thatblends the various f lour streams.

y y

Gravity Feed System


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y y

Advantages of the Gravity FeedSystem:

Requires less equipment than

pneumatic conveying.

The feeder can sit directly on top of aflour collection conveyor, on a platform.

It can be installed on floor directly abovethe collection conveyor with thedischarge spout feeding into a mostly

vertically tube dropping down onto theconveyor.

Gravity Feed System


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New mills can be designed oradapted to allow easy installationof gravity feeder locations. Oldermills may be configured in ways

that makes installation of thistype of system difficult.

If the system is installed above

the collection conveyor, it mayrequire building a platform orpurchasing additional equipment.

y y

Considerations when usinggravity feed systems:

Examples of Gravity Field Setup


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Mixing screw flour conveyor Flour collection conveyors for threedifferent lines of f lour.

p y p

Section 2C



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g q g(slide 1 of 3)

At the front half of collection conveyor above the blades of themixing screw

At least 3 meters of conveyor length is normally needed toensure adequate blending

Poor Too l itt le mixing

Poor Too litt le flour Good

Flour flow

Location of feeder on flour collection conveyor



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Another option for feeder location:If it would be difficult to install the feeder at the beginning of aconveyor, the feeder can be connected to the flour dischargespout of a plansifter:

The sifter flour spout must have a significant amount offlour entering into the flour collection conveyor on the floorbelow.

The sifter flour spout must enter the flour stream at leastthree meters from the discharge end of the collectionconveyor to ensure adequate blending.

The three meter distance can be shortened in mills wherethe flour is:

pneumatically blown from the collection conveyor toeither a packing bin or flour storage bin

the flour collection conveyor discharges into another

conveyor and the total length of the mixing distanceafter the premix is added is at least three meters

g q g(slide 2 of 3)



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In the case of erratic flour f low:

Install mixing conveyor:

One solution for small, older mills without a point of a known, constant flow of flour is toinstall a mixing conveyor running from a flour holding bin to the packout bin. The feederwould drop or blow the premix into the start of the special conveyor.

Slave feeder output to f lour flow:

If the flow of flour is erratic through a conveyor but its flow rate is measurable by somedevise that gives a proportional milliamp signal, that signal can be used to control the

output of the feeder.

(slide 3 of 3)

Equipment Suppliers


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Many companies sell fortification equipment. Mills should ensure that directions for installing

and maintaining equipment are available in the national language, or make arrangements tohave them translated.

When considering equipment, look for these specifications:

o Screw type feed mechanism.

o Automatic shut off capability.

o All surfaces in contact with the premix of sanitary of stainless steel or non-corrosive material.

o Manually adjustable delivery control, calibrated from 0 to 100% of feeder

capacity that can be mounted separate from feeder.o 220 volt ± 10% 50/60 Hz single phase power.

o Agitation mechanism to prevent bridging or tunneling of premix in hopper.

o Capable of delivering from 0.04 to 8 L/hr with ± 5% accuracy over full rangethrough the use of different size screws, gears or belts supplied with feeder.

o Hopper capacity of 8 liter minimum.

o Device to allow operator to easily check if hopper is empty or near empty.

Equipment Suppliers


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Vendor must provide two references of maize or flour mills where thisfeeder has been in operation for at least one year.

Vendor must agree to provide:

o Spare parts of gears, belts, screws, fuses or other parts that themanufacturer is aware of possible replacement in the first threeyears of operation.

o A technician to help install X number of feeders in X number of mills

and to conduct workshops for miller groups on the installation,calibration and maintenance of the feeder.

o Operating instruction book that explains in words and with diagramsthe installation, calibration and maintenance of the feeder.

o A price list of spare parts.

Lessons Learned from Other Millers


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When ordering mil l fortif ication equipment avoid these problems:

Motors with incorrect voltage or numbers of phases supplied (110v vs. 220v, single phasevs. 3-phase, etc)

Required or expected components that are optional and not ordered or substantiallyincreased the cost of equipment.

No spare parts ordered and no mechanism for quickly obtaining spare parts (brass gears,belts, etc)

Feeder designed for use with a specific premix, which did not work well with otherpremixes due to different flow and packing properties.

Feeder placement may need to be located some distance from the flour line so that a

tube/shoot needed to be fabricated to carry the premix to the conveyor (via gravity).

When donor ordered equipment there is seldom detailed expertise. Milling specialistsMUST liaise closely and carefully review order details.

Equipment manuals may come in a different language than that of mill specialists (correctlanguage version of manual must be specified).

Nutrient Specific Information


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Iron

Zinc

Folic Acid

B vitamins

Vitamin A

Calcium

Each of these vitamins and minerals that can be added to flourhas it’s own issues surrounding which forms of the nutrient can

be added, how much to add, etc…For more information on the specific nutrients and theirfortificant forms, choose from the list to the left.

For information on health concerns regarding the over-

consumption of any of these nutrients, please see Section 4: Assuring Quality Control.

For information on what these nutrients do for the body, pleasesee Section 1: Introduction to Flour Fortification.

Iron


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How well people absorb iron from fortificants depends on both the fortificant’ssolubility and the amount of iron inhibitors in the diet. Inhibitors include phytatesand phenolic compounds found in tea, coffee and other foods. Reducing theeffect of inhibitors by adding ascorbic acid, using sodium EDTA or removing

phytates can increase the total amount of iron absorbed from iron fortified foods.Unfortunately, these methods do not work well in wheat based foods.

The goal of fortification should be to use the iron compound that has the greatest

relative bioavailability compared to ferrous sulfate, yet does not causeunacceptable properties in the flour. Cost is also an important consideration.

Types of iron compounds used in fortif ication


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Elemental iron powders (Reduced (Fe0) Iron)

Electrolytic iron

Hydrogen reduced iron

Atomized iron

(all water insoluble)

Ferrous (Fe

2+

) Sulfate (moderately water soluble)

Ferric (Fe3+) Phosphates (water insoluble)

Sodium Ferric (Fe3+) EDTA (water soluble)

Ferrous (Fe2+) Fumarate (nearly water insoluble)

Insoluble Iron Compounds that are


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Soluble in Stomach Acids

These compounds (Ferrous Fumarate) are reasonably well absorbedbecause they are soluble in the stomach of healthy adults and adolescents.

There is some concern regarding absorption levels in infants who may secreteless acid, but absorption is expected to be similar to water soluble compoundsin most people.

Water insoluble compounds cause fewer sensory problems in foods andshould be the fortificant of choice if the water soluble forms causeunacceptable changes. Ferrous fumarate is the most commonly used ironcompound in this group.

Insoluble Iron Compounds that areI l bl i S h A id


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Insoluble in Stomach Acids

These compounds (elemental or reduced iron powders) have a relative bioavailability ofapproximately 20 to 75 percent of ferrous sulfate iron. They are widely used in the foodindustry, however, because they have a lesser effect on the sensory properties of thefoods. These compounds are relatively inexpensive, but should be used as a last resortin areas where the diets are high in iron absorption inhibitors. If used, they should beadded at higher levels than that of ferrous sulfate.

Elemental iron powders are used widely to fortify cereals, but the bioavailability of the

several different types is very dependent on the size, shape and surface area of the ironparticles, as well as the composition of the foods to which they are added.

Only electrolytic iron has been proven to be sufficiently bioavailable for humans, butrecent data indicate that carbonyl iron and some H-reduced iron may have acomparable bioavailability to electrolytic iron.

Water Soluble Compounds


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Ferrous sulfate is the most frequently used water soluble iron fortificant because it isinexpensive. The water soluble iron compounds have the highest relativebioavailability because they are very soluble in the gastric juices. They should be theiron fortificant of choice whenever possible.

However, these compounds are most likely to have adverse effects on the color andflavor of foods during prolonged storage accelerating rancidity. The free iron can alsooxidize some vitamins in the food if they are supplied in the same premix.

The water soluble forms of iron can be useful for fortifying cereal flours that have arelatively fast turnover. But, because ferrous sulfate can cause rancidity dependenton the climate and the fat content of the flour, its suitability as a fortificant should beconsidered before use.

Sodium Iron EDTA (NaFeEDTA)


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Iron is two to three times better absorbed from NaFeEDTA than fromferrous sulfate or ferrous fumarate in foods high in phytic acid.FeNaEDTA does not accelerate rancidity in stored cereals. However,

it may cause color changes in some foods as it is not very soluble inwater. It is more expensive than other types of iron, but less isneeded per metric ton of flour because it is better absorbed. The ironspot test is not compatible with sodium iron EDTA, but other testingmethods are available.

Relative Bioavailability of Iron Sources


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0

1020

30

40

50

60

70

8090

100

% RBV

Ferrous

Sulfate

Electrolytic

US

Electrolytic

India

Hydrogen

Reduced

Atomized

SUSTAIN studies

Relative Biological Value (RBV) is the comparison in bioavailability (ability of the bodyto utilize the added iron) of different iron sources to that of ferrous sulfate, which is100% by definition. The absolute absorption of ferrous sulfate can vary from 5% to30% depending on the iron status of the individual and the composition of the diet.

Types of iron compounds usedi l f tifi ti


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in cereal fortification

Elemental Iron powder (reduced) iron

NaFeEDTAFerrous Sulfate

Ferrous Fumarate

Ferric phosphate

Fortification and Iron Deficiency


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The World Health Organization saysiron deficiency is the most commonand widespread nutritional disorder inthe world. Fortifying flour with ironhelps reduce iron deficiency.

Anemia is measured by serumhemoglobin levels. There are multiplecauses of anemia, but iron deficiencyis the primary one.

Iron deficiency is measured by indicesof body iron stores such as ferritin. Itcan cause a number of healthproblems besides anemia.

Iron Deficiency Anemia (IDA) isindicated by the presence of both lowhemoglobin and low iron stores.

Iron Deficiency

IronDeficiency Anemia

Anemia

Studies on Iron Bioavailability


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Efficacy studies involve a select population that was given a known, controlled diet to see iftheir nutritional status improves.

Effect of different iron sources on iron status – 36 week human efficacy trial

0

10

20

30

40

50

60

% Prevalence

Ferrous

Sulfate

Electrolytic H Reduced Control

Iron deficiency AnemiaSUSTAIN studies



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M o d i f . f r o m C h e n C h u n

m i n g e t a l . ( 2 0

0 5 )

Effect of Iron Fort ification of White Flour on Hb Levels (China)

100

105

110

115

120

125

130

135

Control FeNaEDTA20 ppm

FeSO430 ppm

Elemental Iron

60 ppm

M e a n H b

L e v e l s ( g / L )

0 month

2 months

4 months

6 months

Iron deficiency

Iron supply sufficient



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Effect of 24 ppm Fe as NaFeETDA Flour Fortification on Serum IronLevels in Weichang, China

0.7

0.75

0.8

0.85

0.9

S I ( m g / L )

0 12 24 36

months

Control

Experimental

* Significant difference from control

*

* *



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Effect of 24 ppm Fe as NaFeETDA Flour Fort ification on HemoglobinLevels in Weichang, China

125

130

135

140

H b ( g / L )

0 6 12 18 24 30 36

months

Control

Experimental

* * *

* Significant difference from control

B Vitamins


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Thiamin (B1)

Riboflavin (B2)

Niacin (B3)

Pyridoxine (B6)

Cobalamin (B12)

Folic Acid (B9)

Thiamin (vitamin B1)


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Thiamin Compounds Used

For flour fortification, thiamin mononitrate is the preferred fortificantcompound as it is less soluble in water than thiamin hydrochloride.

Both compounds are white or almost white in color and thus do notaffect the color of the flour product.

Both thiamin compounds are susceptible to losses from exposure to

light and heat and alkaline conditions (pH over 7).

Riboflavin (vitamin B2)


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Riboflavin Compound Used

The only vitamin B2 source used in cereal fortification is riboflavin. It issoluble in water. The compound is yellow in color.

Riboflavin preparations differ in their physical properties and crystallinestructure, which influences its color, solubility and particle size. Onlyproducts designated by the manufacturer for flour fortification should be

considered for use.

Riboflavin compounds are highly unstable when exposed to light.

Niacin (vitamin B3)


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Niacin Compounds Used

Two niacin compounds are commonly used in fortification:nicotinic acid (normally just called niacin) and nicotinamide.

Nicotinamide is soluble in water, while nicotinic acid is relativelyinsoluble in water but soluble in alkaline environments. Niacindoes not cause color changes to the flour as it is white in color.

Nicotinic acid is a vasodilator and can cause a flushing reaction(reddening) in the skin on exposure.

Both niacin compounds are very stable in heat and light.

Pyrodoxine (vitamin B6)


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Pyrodoxine Compounds Used

Pyrodoxine hydrocloride is the pyrodoxine fortificant of choice for flourfortification. It is water soluble. The compound is white in color and thus

does not affect the color of the flour produced.

The pyrodoxine compound is stable to heat, but sensitive to UV light.

Cobalamin (vitamin B12)


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Cobalamin Compounds Used

Cyanocobalamin is the cobalamin fortificant used in flour fortification. Dilutedforms are usually used because only extremely small amounts of the vitamin are

needed. Cyanocobalamin is dark red in color but does not adversely affect thecolor of the flour because of the minute amounts added.

Cyanocobalamin is relatively stable in heat, but unstable in alkali and strongacidic environments.

Analytical Testing

It is very difficult and expensive to test for the small amounts of vitamin B12 usedin fortification. A microbiological test method is normally employed.

Cobalamin Bioavailability

The formulation of cobalamin in fortified foods is absorbed two times more readilythan natural cobalamin occurring in foods.

Folic Acid (vitamin B9)


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Folic Acid Compound Used

Pteroyl monoglutamic acid is the form of folic acid used in fortification.It is light yellow in color, but this does not affect the sensory aspects of

the food because of the small amounts added. The compound isrelatively stable with some loss from exposure to light and foodpreparation.

Pteroyl monoglutamic acid is only slightly soluble in water, but is easilysoluble in the low pH of the stomach.

Folic Acid Bioavailability

Folic acid provided in fortified foods is more readily absorbed thannatural food folate. On average 1.7 times more is absorbed.

Vitamin A


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Vitamin A Compounds Used

Several forms of vitamin A are used in fortification: retinyl acetate, retinylpalmitate and beta-carotene. Beta-carotene has an orange color that makes itunsuitable for flour fortification.

The retinyl esters are available in a protected, spray-dried form for use in flourfortification, sometimes referred to as SD-250 or SD-250S, since they contain250 IU/mg. These forms do not affect the sensory properties of the flour.

Different commercial products can vary in their stability, both in theconcentrated product and in a premix. Significant losses can occur on storageif the encapsulation and antioxidant protection system is poor. A standardstability test at 45° C on the raw material should show losses no greater than

20% after 21 days.

Calcium


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Calcium Compounds Used

The most common calcium fortificantsused in flour fortification are calciumsulfate and calcium carbonate.

Both compounds are white in colorand have a bland taste resulting in nosignificant changes to the flourproduct.

Levels added The level of calcium added ranges

from 1.1 to 2.1 grams/kilogram.

Because these levels are far higherthan the premix addition, calcium isalways added separately.

Ca level 1.1 g/kg 2.1 g/kg

Ca Sulfate 4.8 9.1

Ca Carbonate 2.8 5.3

Level of the calcium salts needed (in grams per

kilogram flour) To be added at the two most

common levels of calcium fortification.

Zinc


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Zinc Compounds Used

Zinc oxide is the most commonly used zinc source for the fortification ofcereals. It is also the least expensive and the source that causes theleast problems with flavor and other organoleptic properties.

Zinc Level

The level of zinc added depends on the average wheat consumption andthe flour extraction rate as well as phytic acid intake from other dietarysources.

Zinc Bioavailability

Zinc absorption depends primarily on the amount of zinc consumed andthe amount of phytic acid present in the food. According to the

International Zinc Nutrition Consultative Groups (IZiNCG), whenconsuming just enough zinc to meet physiological needs, about 27 to 35percent is absorbed from diets with a relatively low amount of phytic acid,while 19 to 26 percent is absorbed from diets with relatively higheramounts.

End of Section 2


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End of Section 2

Continue

Return Table of Contents


Section 3

On the Production Line

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Equipment: Maintenance & Troubleshooting

Premix: Handling, Storage & Management

Installation & Calibration of Premix DosingMachinery

Installation & Calibration ofPremix Dosing Machinery


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Premix Dosing Machinery

Location of Premix Feeders

Feeder Set-up

Feeder Calibration

Fortification Operation Guidelines

Location of Premix Feeders


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Place feeders in a dry location and away from sunlight.Vitamin A, riboflavin and folic acid are sensitive to light andatmospheric oxygen.

Ideally, place feeders in an area of the mill easilyaccessible to the operators. Controller should be handy tothe miller’s office or flour testing station.

There should be room adjacent to the feeders for a supplyof the premix ready to add (a box or two depending on userates).

Feeders should be located near the beginning of theconveyor to assure good mixing with the flour after it isadded.

Feeders Details with Premix Box


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Feeder Details


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Location of feeder on flour collection conveyor


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At the front half of collection conveyor above the blades of the mixingscrew

At least 3 meters of conveyor length is normally needed to ensureadequate blending.

Poor Too lit tle mixing Poor

Too li ttle flour Good

Flourdischarge

Feeder located on platform or floorabove

Premix Feeder Set-up Two lines, two feeders


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In general, one feeder is needed for each production lineof flour to be fortified.

Locate feeders to allow adequate mixing with flour afterpoint where premix is added.

Speed controller and low level indicator light should be inreadily visible, convenient and easily accessible location.

Feeder hopper should be convenient for filling.

Install voltage stabilizers whenever electrical voltagefluctuates more than ± 20%.

Install electrical interlock systems directly to either theflour collection conveyor motor or the mill control panel.

Check low premix level indicator lights to assure hopper isoperating correctly.

Conveyor Direction

Feeder Controller


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Feeder Details(Mongolia example)


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Conveyor

direction

Screw Premix

Feeder

Feeder Calibration


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Check the flour production rate (kg/hr) for each production line, even if therate has been established. his can be done with the following procedure:

While the mill is running, count number of bags packed per 60 minutes