1 Examples of products Physiology of fresh-cut products Preparation and handling Quality aspects of fresh-cut products Fresh-cut Products: Overview and Challenges Marita Cantwell [email protected]http://postharvest.ucdavis.edu "Fresh-cut produce" is defined as any fresh fruit or vegetable or any combination thereof that has been physically altered from its original form, but remains in a fresh state. Regardless of commodity, it has been trimmed, peeled, washed and cut into 100% usable product that is subsequently bagged or prepackaged to offer consumers high nutrition, convenience and value while still maintaining freshness. Fresh-cut Produce • Minimally Processed • Lightly Processed • Partially Processed • Preprepared • Fresh Processed • Pre-cut • Value-added IFPA/UFPA Source: The Perishables Group - The FreshFacts on Fresh Cut, 2006 Fresh-cut Produce Sales via Supermarket Channels,* 2005, $6 Billion Total Packaged salads 53% Veggies* 26% Fruit 21% Carrots=50% of vegetables *Data for 59.2% of grocery ACV, projected to total grocery over $2 million/store channel. Fresh-cut Products References (Summaries on Specific Products) • FRESH-CUT FRUITS (J. Beaulieu, J. Gorny) • FRESH-CUT VEGETABLES (M.Barth, H. Zhuang, M. Saltveit) USDA Agric. Handbook 66. 2004. Commercial Storage of Fruits, Vegetables & Ornamentals (K.Gross et al., eds.); http://www.ba.ars.usda.gov/hb66 • FRESH-CUT FRUITS AND VEGETABLES (M. Cantwell & T. Suslow). 2002. Postharvest Technology of Horticultural Crops, Ch. 36. The Magazine for Value-Added Produce http://www.freshcut.com/ International Fresh-cut Produce Association Technical publications on food safety, packaging; technical seminars, annual conference & expo UNITED FRESH PRODUCE ASSOCIATION http://www.unitedfresh.org/ 2006 Fresh Fresh- cut Vegetables cut Vegetables • Lettuces: cleaned, chopped, shredded • Spinach, leafy greens, washed & trimmed • Broccoli & cauliflower florets • Cabbage, shredded • Carrots, baby, sticks, shredded • Celery sticks • Onions, whole peeled, slices, diced • Potatoes & other roots: peeled, sliced, diced • Mushrooms sliced • Jicama, Squash, cucumber slices, dices • Garlic, fresh peeled, slices
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
"Fresh-cut produce" is defined as any fresh fruit or vegetable or any combination thereof that has been physically altered from its original form, but remains in a fresh state. Regardless of commodity, it has been trimmed, peeled, washed and cut into 100% usable product that is subsequently bagged or prepackaged to offer consumers high nutrition, convenience and value while still maintaining freshness.
Fresh-cut Produce
• Minimally Processed
• Lightly Processed
• Partially Processed
• Preprepared
• Fresh Processed
• Pre-cut
• Value-added
IFPA/UFPA
Source: The Perishables Group -
The FreshFacts on Fresh Cut, 2006
Fresh-cut Produce Sales via Supermarket Channels,* 2005,
$6 Billion Total
Packaged salads
53%Veggies* 26%
Fruit 21%
Carrots=50% of vegetables
*Data for 59.2% of grocery ACV, projectedto total grocery over $2 million/store channel.
Fresh-cut Products References (Summaries on Specific Products)
• FRESH-CUT FRUITS (J. Beaulieu, J. Gorny)
• FRESH-CUT VEGETABLES (M.Barth, H. Zhuang, M. Saltveit)
USDA Agric. Handbook 66. 2004. Commercial Storage of Fruits, Vegetables & Ornamentals (K.Gross et al., eds.); http://www.ba.ars.usda.gov/hb66
• FRESH-CUT FRUITS AND VEGETABLES (M. Cantwell &T. Suslow). 2002. Postharvest Technology of Horticultural Crops, Ch. 36.
The Magazine for Value-Added Producehttp://www.freshcut.com/
International Fresh-cut Produce AssociationTechnical publications on food safety, packaging;technical seminars, annual conference & expo
UNITED FRESH PRODUCE ASSOCIATIONhttp://www.unitedfresh.org/
IFPA, 2004. Fresh-cut Produce Fuels an America on the go. 58 pp.
3
Immediate Physical Effects
Mechanical shock to tissueBruises, cracks, fractures in tissue
Removal of protective epidermal layerAlter gas diffusionProvide entry for contaminants
Cell fluids on cut surface Reduced gas diffusionProvides substrate for microbes
Exposure to contaminantsMicrobial ,Chemical
Abrasion peeling of carrots leads to fragmented cell walls that dry out and result in “white blush”;can rehydrate carrots.
Diagrams from Saltveit, UC Davis
New equipmentautomatically peelsand then cuts the carrots;have less problem with“white blush”
Physiological Effects of Fresh-cut Processing
• Increased respiration rates
• Altered ethylene production rates
• Increases in other biochemical reactions– Discoloration and Color
– Texture
– Aroma and Flavor
– Nutritional quality
Main strategy to minimize changes in physiology is low temperature
Respiration rates of Intact and Shredded Lettuce
Res
pira
tion
(µ
l CO
2. g
-1 h
-1)
0
5
10
15
20
Days storage
0 1 2 3 4 5 6 7 8 9
Res
pira
tion
(µ
l CO
2. g
-1 h
-1)
0
5
10
15
20
Shredded Lettuce
Intact Lettuce2.5°C (36°F)
5°C (41°F)
7.5°C (45°F)
10°C (50°F)
Shredding greatly increased respiration rates Temperature control is
extremely important
• Low temperature minimizes wound response
• Diced onions discolor, decay, soften and lose fluid more readily than whole peeled onions
Storage Temperature
Res
pir
atio
n
(µL
CO
2. g
-1 h
-1)
0
1
2
3
4
5
6
7
8
9
10
11
12 Yellow Onion
Intact
Peeled
Diced
0°C 5°C 10°C
Average Respiration Rates (µL CO2/g-h)
40.629.318.110°C
21.217.410.65°C
Compressed Compressed Air PeeledAir Peeled
Manually Manually PeeledPeeled
Unpeeled Unpeeled ClovesCloves 0
10
20
30
40
50
Days0 2 4 6 8 10 12 14 16 18 20
Re
spir
atio
n (
l CO
2/g-h
)
0
10
20
30
40
50
5ºC (41°F)
Unpeeled Manually peeled Compressed air peeled
10ºC (50°F)
Res
pira
tion
(l C
O2/g
-h)
Careful peeling causes a substantial increase in respiration rates. Mechanical compressed air peeling doubles rates. Rates are significantly less at 5°C. Quality best maintained at 0°C.
0°C
Commercially Peeled Garlic Stored 9 Days
5°C 10°C 15°C
4
Intact and Intact and FreshFresh--cut Kalecut Kale
Respiration rate (mL CO2 kg-1 h-1 )
Product 0ºC 5ºC 10ºC 15ºC
Full size leaves 8 12 29 33
Small leaves 14 21 42 57
Chopped (2 x 2 cm pieces full size leaves)
15 23 46 53
Shredded (0.3 cm pieces full size leaves)
17 28 59 68
Harvest Trim, core, defect removal Cool and/or MA Dump, mechanical cut Cooling, disinfection Drying, centrifugation Component blendingWeigh and package Metal detector, pack, palletize Temporary cold storage
Lettuce Salad Preparation
1. Harvest lettuce from first harvest results in better quality
trim outer leaves
2. Field-pack & local transport plastic bins or totes/ carton boxes or bins; avoid wood bins
transport on flatbed trucks; if distances far, transport in refrigerated trailer
3. Vacuum or forced-air cooling field temperatures and delay determine need to cool
vacuum and forced-air cooling most common
4. Reception, dump, trim and core revision and selection of heads on conveyer
further trimming outer leaves; removal of stem tissue with coring device
Preparation of Lettuce Salads
Often Done in the field
Preparation of Lettuce Salads, cont.
5. Chop/shred/tear continuous-feed cutter for salad pieces (3 x 3 cm) or shreds (<0.5 cm)
manual cutting for some lettuce types (romaine) very sharp knives reduce damage and subsequent browning
6. Wash and Cool Cold water containing disinfectant, usually chlorine
residence time form 15-30 sec; may use processing aides to reduce browning
7. Centrifugation or other drying technique vibration screens remove large volumes of water
centrifugation and air tunnels remove moisture so surface of product dry basket centrifuges of different sizes depending on product
8. Combine different products for salad mixes or “color” items may be added after washing and centrifuged together
In facility at low temperature 3-5°C
Preparation of Lettuce Salads, cont.
9. Package in plastic film bags centrifuged product dumped onto conveyor feeding filler
manual or automated form-fill-seal machines vacuum or gas-flushing with nitrogen
check for leakers in pressurized water chamber
10. Box, palletize and store temporarily Bags through a metal detector, conveyor to boxing and palletizing area
Temporary storage <5ºC (<41ºF); 0°C (32°F) is optimum
11. Transport to food service outlets and/or retail markets Pre-cooled clean trucks; thermostat at <5°C (41°F) Load at enclosed docks to maintain cold chain
5
Washing Disinfecting Rapid cooling Cut to 2 inch sections Mechanical Peeling Mechanical shaping Disinfection Cooling Computerized quality and color sorting Packaging (form, fill, seal)
Processing Baby Peeled Carrots
Onion ProcessingRaw material qualityPackaging and odorsPhysical damageTemperature control
Many large volume (lettuces) products are mechanically cut, but manual preparation generally results in superior quality
cutting romaine by hand; eliminate defects manually peeled garlic vs compressed air peeled broccoli and cauliflower florets manually trimmed manually trimmed and cut melons, pineapples
SANITARY PLANT DESIGNFocus: Implementation of GMP’s
Rudi Groppe; http://www.heinzen.com/products/
Design efficient, easy to clean & sanitize processing plants
Mobility of equipment 2-3 areas to separate production steps
Total Microorganisms at Different Steps Total Microorganisms at Different Steps of a Freshof a Fresh--cut Salad Process Linecut Salad Process Line
Bin Dump 92,000
Coring Belt 210
Cutter 2,290
Transfer Belt 40
Cooling Water 5
Centrifuge 10
Package Filler 3,350
Operation Number/Sq. Inch
Modified from Hurst, Univ. Georgia, 1990
6
Fresh-cut Products
Food Safety Requirements
•• Meticulous cleanliness of equipment, Meticulous cleanliness of equipment, employees and productemployees and product
•• Rigid maintenance of refrigerated Rigid maintenance of refrigerated temperaturestemperatures
•• Complete integrity of packagesComplete integrity of packages
•• Strict adherence to product use by dates Strict adherence to product use by dates & handling instructions& handling instructions
“Best if used” by datesUSDA Inspection guidelines but no standards
Wounds induce Wounds induce phenolicphenolic metabolismmetabolismLeading to unsightly brown pigmentsLeading to unsightly brown pigments Enzymatic Browning
PALPhenylalanine cinnaminc acid other phenolics
PPO+ O2 (o-Diphenol oxidase)
(Laccase)
complex brown polymers quinones
PAL = phenylalanine ammonia-lyasePPO = polyphenol oxidase
5
4
3
2
1
Salad Lettuce Cut edge browningWound induction of PAL
and brown pigments Lettuce types and varieties
differ in PAL and browning
Days at 5°C (41°F)
0 1 2 3 4 5 6 7
PA
L
acti
vit
y (
µm
ol c
inn
am
ic a
cid
. g-1
. h-1
)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0Green LeafRed LeafButterhead
IcebergRomaine
5% LSD
Days at 5°C (41°F)
1 2 3 4 5 6 7 8
Res
pira
tion
rate
(µ
L/g-
h)
0
3
6
9
12
15
18
21 A. Intact leavesHeart Young Midsize Full size
Days at 5°C (41°F)
1 2 3 4 5 6 7 8
B. Salad-cut leaves (2 x 2 cm)
Romaine lettuce: leaf position/age effect on respiration, discoloration and composition
Phenolics highest in outer leaves; browning highest in outer leaves Sugars highest in heart leaves Chlorophyll/carotenoids highest in outer leaves Vitamin C not much affected by leaf age or position
Ermen, Hong, Cantwell, 2006
7
Control
1-MCP
Air CAcv Pic
Nov 2004, 1000ppb 1-MCP at 5°C; 8hr after harvest, CA=1%O2+9%CO2
4 days 5°C
Prevention of enzymatic/oxidative browning
• Refrigeration (slows enzymatic reactions)
• Exclusion of oxygen (CA, MAP, edible films)
• Inhibition of PAL (lettuces & vegs)
• Inhibition of PPO (fruits)
• Use of reducing agents (ascorbic acid, etc.)
• Other chemical agents
Packaged Salad Quality Study
• 4 salad products from 5 processors• 4 production dates, product purchased• Products stored at 5°C (41°F)• Components: Size, Color
There are many opportunities There are many opportunities for damage to spinach leaves for damage to spinach leaves HarvestHarvest Bin dump, sort areaBin dump, sort area Wash and centrifugeWash and centrifuge Packing Packing
Information courtesy of Dr. G.S. Mudahar, Salad Time Farms, Inc.
3
4
5
6
7
0 2 3 4 5 6 7 8 9 10Days
Te
mp
erat
ure
(°C
)
1
At plant
Retail Store Cooler
Retail Shelf
DistanceTransport
LocalDistribution
Fresh-cut produce Chill Chain Temperatures During Shipping, Distribution and Retail Display.
We can do better!!
Good Temperature Control throughout handling and distribution is a Necessity for Fresh-cut Products
9
Vegetable trays- want 18 day shelf-life
Products in tray and compatibility issues- raw material sourcing and handling before prepare - shelf-life of individual products in tray varies- temperature; 5°C too low for grape tomatoes- modified atmospheres—not good for all products in tray
A) Increased Technical & Managerial A) Increased Technical & Managerial SophisticationSophistication
B) Understand & Manage Fruit B) Understand & Manage Fruit Ripening Ripening
C) Overcome Sourcing IssuesC) Overcome Sourcing Issues
D) Reduce Labor CostsD) Reduce Labor Costs
E) Retain Flavor and AromaE) Retain Flavor and Aroma
The Successful FreshThe Successful Fresh--cut Fruit Processorcut Fruit Processor
Management of Ripening of Intact and Fresh-cut Fruits - Considerations
1. Stages of fruit developmentStages of fruit development
2.2. Fruits that must ripen on the plantFruits that must ripen on the plant
3.3. Fruits that can ripen on or off the Fruits that can ripen on or off the plantplant
4.4. Role of ethylene in fruit ripeningRole of ethylene in fruit ripening
5.5. Efficacy of 1Efficacy of 1--methylcyclopropene in methylcyclopropene in extending shelfextending shelf--life of freshlife of fresh--cut fruitscut fruits
13
Cut ripe pineapple cubes have a longer post-cutting life than those cut green
Adel Kader
Classification of fresh-cut fruit products according to their potential post-cutting-life at optimum handling conditions (0-5ºC and 90-95% RH)