Presentation 3.2 Food Deterioration and its Causes.
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Transcript of Presentation 3.2 Food Deterioration and its Causes.
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Presentation 3.2
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Presentation 3.2
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Food Deterioration and its Causes
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• What is food deterioration, and how can food science minimize its effects?
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Food deterioration includes:
• changes in organoleptic quality (how something is perceived by a sensory organ)
• nutritional value• food safety• aesthetic appeal• color
• texture
• flavor
To some degree, all foods undergo deterioration after harvest. The role of food science is to minimize negative changes as much as possible.
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Presentation 3.2
Product quality at harvesting
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Presentation 3.2
Product quality after improper mechanical
grading process.
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Presentation 3.2
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LOSS OF HORTICULTURAL CROPS
Loss in quantity and quality between harvest and consumption:
5 - 25% in developed countries
20 - 50% in developing countries
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CATEGORIES OF DETERIORATION
any change in the appearance, smell, or taste of a food product that makes it unacceptable to the consumer.
Food DETERIORATION results in economic loss to producers, distributors, and even consumers.
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Causes of Food Deterioration
• Phisiology• Microbial spoilage • Chemical reactions can also reduce food quality
– Exposure to air or light (oxidative rancidity)– Reactions caused by enzymes in the food
leading to off-flavors– Other chemical reactions/interactions
• Cold storage temperatures can minimize chemical re
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Table 1. Useful ShelfLife at 70 F
• Food Days
• Meat 1 to2
• Fish 1 to 2
• Poultry 1 to 2
• Dried, smoked meat 360+
• Fruits 1 to 7
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Table 1. Useful ShelfLife at 70 F
• Food Days
• Leafy vegetables 1 to 2
• Root Crops 7 to 20
• Dried seeds 360 +
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The three general categories of food deterioration are:
• Physical• Chemical• Biological • Factors that cause food deterioration
include: light, cold, heat, oxygen, moisture, dryness, other types of radiation, enzymes, microorganisms, time, industrial contaminants and macroorganisms (insects, mice, and so on).
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WHAT CAUSES FOOD DETERIORATION?
• Deterioration can be caused by one or more of the following:
• Microorganisms such as bacteria, yeast and molds; • Activity of food enzymes; • Infestations by insects, parasites and rodents; • Inappropriate temperatures during processing and
storage; • Gain or loss of moisture; • Reaction with oxygen; • Light; • Physical stress or abuse; and • Time.
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BIOLOGICAL CHANGES CAN INCLUDE
• WILTING
• DISCOLORATION
• SLIME FORMATION/COAGULATION
• OFF-FLAVORS
• OFF-ODORS
• EXCESSIVE MICROBIAL NUMBERS/TOXINS
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CHEMICAL CHANGES CAN INCLUDE
• OFF-FLAVORS
• OFF-ODORS
• DISCOLORATION (BROWNING, FADING)
• TEXTURAL CHANGES
• CONTAINER INTERACTIONS
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CONTROL OF CHEMICAL CHANGES
• AVOID EXCESSIVE HIGH TEMPERATURES
• AVOID EXPOSURE TO LIGHT• MINIMIZE EXPOSURE TO OXYGEN• PROPER PROCESSING TO
MINIMIZE MAILLARD REACTIONS DURING PROCESSING
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Presentation 3.2
Reduce losses:
1. Understand biological en environmental factors involved in deterioration
2. Use postharvest techniques that delay senescence and maintain the best possible quality
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BIOLOGICAL FACTORS INVOLVED IN DETERIORATION
1. Respiration
2. Transpiration
3. Growth and development
4.Compositional changes
5. Physiological breakdown
.6.Pathological breakdown
7. Physical damage
Nest of gray mould
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ENVIRONMENTAL FACTORS INFLUENCING DETERIORATION
2. Relative humidity
3. Atmosphere composition
4. Ethylene
5. Light
1. Temperature
Leather rot
Rhizopus rot
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Presentation 3.2
• Product quality maintenance Product quality maintenance (reduce loses)(reduce loses)
• Generate product added Generate product added value value
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Presentation 3.2
Key processes during the
post-harvest- life :
• Respiration .
• Transpiration .
• Maturity process.
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Typical life cycle of living tissues
Development/growth (metabolic,biosynthetic reactions)
↓Maturation
↓Ripening
↓Senescence (catabolic, degradative reactions)
↓Deterioration
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BIOCHEMICAL REACTIONS OF RESPIRATION
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Plants have the ability to utilize energy from sunlight for synthesis of carbohydrates using CO2 and H2O in the air; photosynthesis.
CO2 + H2O + (sunlight) (CH2O)n + O2
Organisms consume carbohydrates and convert them into energy through an enzymatic process called respiration.
C6H12O6 + 6O2 6CO2 + 6H2O + 673 Kcal
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Presentation 3.2
Factors affecting the respiration rate of FFV:
Internal:Internal:
Type of tissue or organ: Leaves > fruits> roots. Product size: bigger size< respiration rate. Stages of development: young leaves >respiration. In fruits will depend on their classification as climacteric or non-climacteric.
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Presentation 3.2
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PERISHABILITYINDEX
Very high
High
Moderate
Low
Very low
POTENTIAL LIFEPOTENTIAL LIFE(WEEKS)(WEEKS)
< 2 weeks
2 - 4 weeks
4 - 8 weeks
8 - 16 weeks
> 16 weeks
PRODUCTSPRODUCTS
broccoli, cauliflower,blackberry, strawberryavocado, pineapple,celery, tomatolemon, watermelonmango, potato,onion, apple,garlic, pear
nuts, dried fruits.
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Presentation 3.2
Factors affecting the respiration rates:Factors affecting the respiration rates:
External:External:
mechanical damage and product’s sanitary condition. temperature. atmosphere composition (< Oxygen and CO2< respiration; > ethylene > respiration). physical barriers (waxes, plastic films, etc.)
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Presentation 3.2
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Presentation 3.2
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• At temperatures above the optimum, the rate of deterioration increases 2 to 3 fold for every 10ºC rise in temperature.
• High temperature-increases the transpiration rate.
Res
pira
tory
rhy
thm
Time
10ºC
20ºC
30ºC
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Presentation 3.2
Loss of water, as vapor, from the product’s area exposed to the air, throughout the cuticle, lenticels, stomas, etc. It depends on:
Internal factors:Internal factors:
species and variety. type of tissue.
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Presentation 3.2
External factors:External factors:
Relative Humidity (<RH> transpiration). Temperature (> temperature> transpiration) Altitude (higher altitude< transpiration).
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Presentation 3.2
Relative humidity management.Relative humidity management.
Is the moisture content (as water vapor) of theatmosphere, expressed as a percentage of the
amount ofmoisture that can be retained by the atmosphere at agiven temperature
RH can influence water loss, decay development,incidence of physiological disorders, and uniformity offruit ripening.
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Presentation 3.2
• Curing.
• Waxes and others surface coatings .
• Polymeric films for packing.
• Avoiding physical injuries.
• Adding water to those commodities that tolerate misting with water.
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Air in the internal Cavity
Wax layer restricts the gases interchange.
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Presentation 3.2
• Wetting floors in storage rooms.
• Adding crushed ice in shipping containers
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Presentation 3.2
Physiological process that occur at the cellular level. After finishing the anabolic process, a series of catalytic reactions start –degradation of: chlorophyll, aromas, organelles and finally causing cellular collapse/death.
Post-harvest technology: to delayPost-harvest technology: to delayas long as possible, the tissue as long as possible, the tissue
disintegration/senescence phasedisintegration/senescence phase
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Ripening Of Fleshy Fruits
• Last part of the fruit development process
FruitFreshWeight
Pollination/Fertilization
CellDivisionPeriod
Cell Expansion Period
Ripening PeriodRipening Period
Maturity (Full sized fruit)
Time
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Ecological Function of Fruit Ripening
• Ripening must happen when the seeds are mature
• In order for ripening and seed maturity to happen together, the plant must control the process
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So What Is Ripening?
• Increase in “sweetness” due to conversion of starch sugars
• Softening due to a breakdown of cell walls
• Less “tartness” due to decrease in acidity
• Increase in flavor compounds
• Color change
• Changes in respiration due to all
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Starch to Sugar Conversion
Sugar
Starch
Days
%
Banana
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Softening of Fruit
Days in storage
Soluble pectin
Firmness
Fru
it F
irm
nes
s, k
g p
ress
ure
% c
on
ten
t o
f so
lub
le p
ecti
n
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Pectin Substances-Plant Gums
• Plant cell wall showing Pectin
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Pectin Substances-Plant Gums
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Pectin Substances-Plant Gums
• Role of Pectin in Plant Tissue (fruits)– In outer cell walls, closely associated with
cellulose – precursor of pectin: Protopectin– Absorb water and transfer it among cells– Responsible for firmness, texture (fruits &
veggies)– Softening during ripening– Breakdown of colloidal stability in fruit juices
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Pectin Substances-Plant Gums
• Change in pectin substances during ripening– Protopectin in middle lamella between cell
walls soluble pectin• Reduce cell wall thickness• Softening & Ripening
– Decrease the degree of esterification of carboxyl groups with methyl alcohol
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Pectin Substances-Plant Gums
Pectin is a polymer of α-Galacturonic acid with a variable number of methyl ester groups.
Methylated ester of Polygalacturonic acid
Chains of 300 to 1000 glalacturonic acid units
Joined with 1α→4 linkages
This structure shown here is three methyl ester forms (-COOCH3) for every two carboxyl groups (-COOH)
hence it is has a 60% degree of esterification, normally called a DE-60 pectin
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What is Control Mechanism?
• That insures:
“ripening and seed maturity
happen together”
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Controlling Ripening
• The mechanism plants use is a gas:
• Ethylene: C2H4 produced in response to seed maturation (less auxin???)
• How does ethylene control ripening?– Stimulates production of enzymes that
• Convert starch to sugar• Break down cell walls• Break down acids
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Ripening Of Fleshy Fruits
IncreasingFruitFreshWeight,RespirationLevel,GasProductionEtc.
Pollination/Fertilization
CellDivisionPeriod
Cell Expansion Period Ripening Period
Ethylene
Flavorcomponents
Respiration
Optimum storage stageOptimum eating stage
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STRAWBERRY –EXTERNAL COLOUR CHANGES. STRAWBERRY –EXTERNAL COLOUR CHANGES.
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• Loss of chlorophyll (undesirable in veg.)• Production of carotenoids and
antocianines. • Starches conversion into sugars. • Changes in organic acids, proteins and
fats. • Reduction in tannins and fungistatic
compounds.
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MANGO-INTERNAL COLOUR CHANGES
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Presentation 3.2
Avoid the negative Avoid the negative effect of effect of external external
factorsfactors
To reduce and delay the action of the internal internal
factorsfactors that are responsible for product deterioration
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Preservation Methods: Refrigeration/chilling : some fresh
produces can rapidly deteriorate under unrefrigeration, which affect the EP cost to be greater. Some precuts and convenience fresh produces such as salad greens should be delivered at temperature of approximately 34 ̊ F to 36 ̊F.
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Presentation 3.2
Waxing: The wax prevents moisture loss and also contributes to the appearance of the produce. Some items likely to be waxed are apples, avocados, bell peppers, cantaloupes, cucumbers, eggplant, grapefruit, lemons, limes, melons, oranges, parsnips, passion fruit, tomatoes, and etc.
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Controlled-atmosphere storage: This room is sealed and oxygen is removed, then variety of other gases are introduced in order to retarding spoilage and reducing the rate of respiration, but the produce that will rapidly deteriorate after removed from the controlled room.
Chemically treated produce: The produce will have a longer shell life.
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What is chilling?
• A unit operation in which temperature of a food is reduced between -1 and 8 C.
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Effect of temperature
• Biochemical changes caused by micro-organisms and naturally occurring enzymes increase with temperature.
Therefore, by reducing temperature we reduce the biochemical changes.
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Why we chill foods?
• To reduce the rate of biochemical activity (respiratory rate of foods)
• To reduce the rate of microbial activity• To preserve sensory and nutritional value of
foods• Consumers consider chilled foods, because
easy to prepare, high quality, healthy natural and fresh
Enhances Shelf life
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Presentation 3.2
Temperature control.Temperature control.
• Product protection from sun heat (full sunlight) after harvesting.
• Pre-cooling treatments to remove field heat.
• Refrigeration.
• Maintaining the cold chain.
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Presentation 3.2
• Key factor affecting product deterioration rate.
• is the most effective tool for extending the shelf life of fresh horticultural commodities.
• Key effect on spores germination and pathogenic growth.
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Presentation 3.2
Temperature (°C)
Assumed Q10*Relative
velocity of deterioration
Relative post-harvest life
Loss per day (%)
0 1 100 110 3 3 33 320 2.5 7.5 13 830 2 15 7 1440 1.5 22.5 4 25
Source: Kader & Rolle (2003)
Effect of temperature on deterioration rate of a non-chilling sensitive commodity
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Presentation 3.2
Temperatures above or below theoptimal range, can cause productdeterioration due to:
• Chilling injury.• Freezing injury.• Heat injury.
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Presentation 3.2
• Chilling Injury
• Chilling injury causes undesirable physiological changes (external or internal browning, skin blemishes, failure to ripen)
• Fruits and vegetables undergoing chilling injury should be stored above a certain temperature
• Chilling injury results from imbalance of metabolic activity
• There is an overproduction of some toxic metabolites
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Examples of foods undergoing chilling injury
• Apples (<2-3 C)
• Bananas (< 12-13 C)
• Lemons (< 14 C)
• Mangoes (<10-13 C)
• Melons, pineapples, tomatoes
(< 7-10 C)
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Presentation 3.2
Lowest safe temperature
(°C)Commodities
3 Asparagus, cranberry, jujube4 Cantaloupe, certain apple cultivars (such as McIntosh and Yellow Newton), certain avocado
cultivars (such as Booth and Lula), lychee, potato, tamarillo5 Cactus pear, cowpeas, durian, feijoa, guava, kumquat, lima bean, longan, mandarin,
orange, pepino7 Certain avocado cultivars (such as Fuerte and Hass), chayote, okra, olive, pepper,
pineapple, pomegranate, snap bean10 Carambola, cucumber, eggplant, grapefruit, lime, mango (ripe), melons (casaba, crenshaw,
honeydew, persian), papaya, passion fruit, plantain, rambutan, squash (soft rind), taro, tomato (ripe), watermelon
13 Banana, breadfruit, cherimoya, ginger, jackfruits, jicama, lemon, mango (mature-green), mangosteen, pumpkin and hard-rind squash, sapotes, sweet potato, tomato (mature-green), yam
Source: Kader & Rolle (2003)
Classification of chilling-sensitive fruits and vegetables according to their lowest safe temperature for transport and storage
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Heat of respiration (Watts/tonne)
0 C 10 C 15.5 C
Apples 10-12 41-61 58-87
Bananas 73-82 65-116 -
Oranges 9-12 35-40 68
Carrots 46 93 -
Potatoes - 20-30 -
Source: Leniger and Beverloo (1975) and Lewis (1990)
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Presentation 3.2
• Freezing produces an immediate collapse of tissues and total loss of cellular integrity.
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Presentation 3.2
Heat injury:
Direct sources of heat can rapidly heat
tissues to above the thermal death point of
their cells, leading to localized bleaching or
necrosis or general collapse.
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Presentation 3.2
Objective:Objective: to remove the field heat. to remove the field heat.
Movement of the caloric energy from the product to the cooling substance.
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Air in the internal Cavity
Wax layer restricts the gases interchange.
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Presentation 3.2
Modified and controlled atmosphere storage
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21% Oxigene0.35% CO2
2% O21% CO2
Filters
Cold room0ºC
Apples, as any living entities..breath
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Presentation 3.2
Range of storage duration (months)
Commodity
More than 12 Almond, Brazil nut, cashew, filbert, macadamia, pecan, pistachio, walnut, dried fruits and vegetables
6-12 Some cultivars of apples and European pears3-6 Cabbage, Chinese cabbage, kiwifruit, persimmon, pomegranate, some cultivars of Asian
pears1-3 Avocado, banana, cherry, grape (no SO2), mango, olive, onion (sweet cultivars), some
cultivars of nectarine, peach and plum, tomato (mature-green)<1 Asparagus, broccoli, cane berries, fig, lettuce, muskmelons, papaya, pineapple, strawberry,
sweet corn; fresh-cut fruits and vegetables; some cut flowers
Classification of horticultural crops according to their controlled atmosphere storage potential at optimum temperatures and relative humidifies
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• Modify the concentration of gases in the produce packing.
• Reduce respiration rate.• Reduce ethylene action.• Delay ripening &
senescence.• Increase product’s shelf
life.
O2
CO2
O2 CO2
21% O2 0.035% CO2
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Presentation 3.2
• Use of MAP during packing is highly increasing.
• Usually designed to maintain 2% - 5% of O2 and 8% - 12% of CO2, extend shelf life of fresh-cut fruits and vegetables.
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MODIFIED ATMOSPHERE MODIFIED ATMOSPHERE PACKAGING (MAP)PACKAGING (MAP)
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Respirasi
C6H12O6 + O2 ------- CO2 +H20+ Energi (ATP) PANAS
O2
CO2
EnergyATP
H2O
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DEFINITION• Modified atmosphere is a condition of atmosphere (normally in a package of
commodity) around the commodity that is different from that of air (78.08% N2, 20.95% O2, and 0.03% CO2).
• Usually this involves reduction of O2 and/or elevation of CO2 concentrations.• Modified atmosphere packaging (MAP) involves the exposure of produce to
the atmosphere generated in a package by the interaction of produce, the package and the external atmosphere.
• Different additives that may affect the atmosphere may be introduced into the package before it is sealed.
• The main feature distinguishing MAP from controlled atmosphere (CA) is that , in the case of MAP, active human involvement stops at the moment of sealing.
• Wide spectrum of techniques of MAP from Individual sealed packaging to the more intricate control of microorganisms in the new package of salad bar items.
• MAP is a multidisciplinary technology of maintaining freshness that utilises basic principles of chemistry, physics, plant physiology and pathology, microbiology, food science, engineering, polymer chemistry.
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CO2i CO2e
O2i O2e
The MAP SystemPlastic FilmAreaVolumePermeability O2Permeability CO2thcikness
ProduceWeightOxygen uptakeCO2 Production
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MAP should be considered as a supplement to proper temperature and relative humidity management
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PRINCIPLES OF MAP
• MAP is a dynamic system during which respiration and permeation occur MAP is a dynamic system during which respiration and permeation occur simultaneously.simultaneously.
• Factor affecting both respiration and permeation must be considered when Factor affecting both respiration and permeation must be considered when designing a package.designing a package.
• Commodity mass, temperature, OCommodity mass, temperature, O22, CO, CO22, and C, and C22HH44 partial pressure and partial pressure and
stage of maturity are known to influence respiration in a package.stage of maturity are known to influence respiration in a package.
• Type, thickness, intended holes, and surface area of packaging film, as well Type, thickness, intended holes, and surface area of packaging film, as well as temperature, RH, and gradient of Oas temperature, RH, and gradient of O22 and CO and CO2 2 partial pressures across partial pressures across
the film, are known determinant of permeation.the film, are known determinant of permeation.
• Package equilibrium or steady state is defined as the point at which the Package equilibrium or steady state is defined as the point at which the commodity COcommodity CO22 production and O production and O22 consumption rates are equal to the consumption rates are equal to the
permeation rates of the respective gases through a package at a given permeation rates of the respective gases through a package at a given temperature.temperature.
• Poorly designed package will become anaerobic or develop unacceptable Poorly designed package will become anaerobic or develop unacceptable levels of COlevels of CO22 before equilibrium is achieved before equilibrium is achieved..
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MAP for fruits and vegetables• Various films have been used
for packaging F&V to minimize respiratory anaerobiosis and potential microbiological hazards
• In China and Japan sealed-packaging has become a common new technique for citrus fruit storage.
• Sealed-package of many F&V are commonly available on the shelves of supermarket.
• One of the novel approaches in MAP of F&V is the introduction of a gas mixture of desirable composition into a package before sealing.
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Presentation 3.2
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Presentation 3.2
• CA is used for transporting and storage of apples, pears, less used in kiwifruits, avocados, nuts, dry fruits and persimmon.
• MA- for long distance transport is used in mangoes, apples, bananas, avocados, plums ,strawberries, blackberries, peaches, figs, nectarines.
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Food Preservation
• So, how does food preservation work?• All of the food preservation processes work by slowing down
the activity and growth of disease causing bacteria, or by killing the bacteria all together. They also slow down or stop the action of enzymes which can degrade the quality of the food.
– Temperature
– Water Activity
– pH
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Food Preservation• Food preservation is the process of treating and handling food in such a way as to stop or greatly slow down
spoilage to prevent foodborne illness and extend its shelf-life.
• Food processing methods that are used to preserve foods include:
– Refrigeration and freezing
– Canning
– Irradiation
– Dehydration
– Freeze-drying
– Pickling
– Pasteurizing
– Fermentation
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Cold storage
• Chilling – slowing microbical growth – reduce enzymatic and chemical reactions– slow postharvest metabolism– reduce moisture loss
• Freezing – slowing microbial and chemical reactions – water immobilization– reducing molecular mobility – some microbial destruction
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Control of redox potential
• CA/MAP– prevent postharvest ripening– reduce microbial activity
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Reducing aw
• drying
• freeze-drying
• humectants
• freezing– slowing microbial and chemical reactions– water immobilization– reducing molecular mobility
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Fermentation
• inhibition of spoilage/pathogenic flora by beneficial microbial flora
• consumption of substrate for biochemical/chemical reactions
• production of antimicrobials
• acidification
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Preservatives
• acidification – pH change– antimicrobial property
• other preservatives – antimicrobial– antioxidant– enzyme inhibitor– control redox potential
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Chilling
• texture degradation in vegetables
• cold shortening of muscle foods, staling of bread
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Freezing
• small many crystals desired, fast freezing entrapment of solutes, less than max concentration in the unfrozen phase
• large crystals, slow freezing max concentration of solutes, tissue damage, partial dehydration,
• local freeze concentration• freezer burn, sublimation of ice, dry brown spots on
poultry, beef• antimicrobial effect due to concentration, intracellular
freezing• destabilization of proteins, vitamin and pigment
degradation, oxidation of lipids
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Concentration and dehydration
concentration > 20% moisture
dehydration < 20% moisture
evaporation, crystallization, sublimation, membrane separations
microorganisms survive, can recover, grow depending on aw
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Modified atmosphere
• closed storage rooms, allow respiratory activity
• in packaging, remove air, replace with other gases, N2, CO2
• vacuum packaging
• vacuum, nitrogen: cheese, meat
• CO2 : fruits and vegetables, meat
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Packaging
• glass, metal, plastics, paper• transport of gases, water vapor, low MW
components• resistance (mechanical, heat, chemical)• oxygen, carbon dioxide, moisture
permeability• light transmission• inertness
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Aseptic packaging
1. product sterilization
2. package sterilization
3. Aseptic filling and sealing
Longer shelf life, better quality (?)
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Hurdle technology
developed for limiting the growth of microorganisms in nonsterile foods (Leistner, 1978)
combined effects of preservation methods > sum of effects individually or large amounts of a single factor
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Hurdle technology
has been used unintentionally
pickles pH + preservative (acid) + salt
sausage
aw + smoke + salt + spices + preservativesIMF (dried fruit, soft cookies)
aw + heating + preservatives pastırma
salt + spices + aw
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•Thank you
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Presentation 3.2
Climatic conditions:
• Temperature and light intensity can influence the content of ascorbic acid, carotenes, riboflavin, thiamine and flavonoids.
• Rainfall affects the water supply and the susceptibility of plant organs to mechanical damage and decay.
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Presentation 3.2
• • inappropriate Infrastructure for produce inappropriate Infrastructure for produce packaging and storage.packaging and storage.• • improper transport conditions.improper transport conditions.• lack of planning (i.e.. harvesting). • lack of planning (i.e.. harvesting). • delays, improper conditions during • delays, improper conditions during distribution and marketing.distribution and marketing.
Primary damages are the result of inappropriate technologies and handling during the post-harvest chain:
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Presentation 3.2
• during periods of oversupply-poor handling increase.• poor or inappropriate harvesting techniques.• poor produce handling. • damages originated during handling and transport. • delays during the distribution process.• loses of weight and water.
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Presentation 3.2
Other Other treatmentstreatments
Pre-coolingPre-cooling
DryingDrying
Selection,Selection,cleaning cleaning
and and disinfectiondisinfection
ReceptionReception
Grading Grading
Packing and Packing and packagingpackaging
StorageStorage TransportTransport
HarvestingHarvesting
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Presentation 3.2
• inappropriate maturity at harvest (over ripening increases sensitivity to quality decay ; immature fruits market rejection).• inappropriate harvest technique (mechanical damages-physical injuries).• climatic conditions at harvesting (free water, exposition of product to direct sun light )• harvesting wet products (increase sensitivity to quality decay) • inappropriate harvesting recipes/containers ( physical injuries).
HarvestinHarvestingg Associated hazardsAssociated hazards
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Presentation 3.2
RecommendatioRecommendationsns
• training personnel on optimum maturity indices. • Application of appropriate maturity indices based on: external quality color, consistence, phenological stage, etc.• Harvesting time: early in the morning or late in the afternoon in order to minimize the sun effect. • Optimizing harvesting recipes/containers (size, materials, height, number of produce layers, conditions, etc. ) • protection of product of direct sun intensity.
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Presentation 3.2
• uncovered areas (direct exposition of products to sun light and adverse climatic conditions) • inappropriate handling of the product during loading and unloading. • inappropriate product heaping (mechanical damages).• delays in the operations (if conditions are inappropriate they can generate increasing product temperature and quality decay) • lack of planning during harvesting (increase delays in the operations).• no methods applied to remove field heat or use of inappropriate ones.
Produce Produce receptionreception
Associated hazardsAssociated hazards
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Presentation 3.2
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Presentation 3.2
Possible Hazards associated
Pre-coolingPre-cooling
Definir actores/roles/Expectativas.If the methods of pre-cooling are inappropriate, they
can:• produce dehydration of the product (i.e.. high speed of cooling air) • tissue damage –i.e. as result of inappropriate packing -product contact with ice. • produce quality decay caused by sensitivity of the product to water exposition.• accelerate quality decay by accumulation of water in some areas of the product (between leaves and calyx)
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Presentation 3.2
Definir actores/roles/Expectativas.Cleaning and Cleaning and
disinfectiondisinfection
Definir actores/roles/Expectativas.Washing methods:
Web methods:• Immersion (product floating).• Spraying .
Dried methods:• Brushing.• Inhalation/aspirate.
Objective: Removing impurities from the product.
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Presentation 3.2
Definir actores/roles/Expectativas.Cleaning and Cleaning and
disinfectiondisinfection
Definir actores/roles/Expectativas.• product water sensitivity.
• poor water quality.• mechanical damage (inappropriate conditions of brushes, etc).• water accumulation in the product can cause product quality decay.
Possible Hazards associated
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Presentation 3.2
Associated Hazards
GradingGrading
Mechanical damages by vibration, impact/hitting, compression, etc. caused either by poor handling or inappropriate equipment maintenance and design.
Grading methods: by size, weight, color, etc.
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Presentation 3.2
Packing and Packing and packagingpackaging
Definir actores/roles/Expectativas.
• poor packing design (reduces efficiency and increases the risk of mechanical and biological hazards).• improper packing (lack of ventilation, low material resistance, sharp and wrinkled surfaces, etc.).• Over packing (many product layers).
Associated Hazards
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Presentation 3.2
Definir actores/roles/Expectativas.
• Inappropriate pile up during packing. • packing products with different degree of maturity.• mechanical damages caused by personnel or improper design of mechanical grading machines.• Problems regarding over-handling of products and inappropriate process flows during post-harvest handling.
Packing and Packing and packagingpackaging Associated Hazards
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Presentation 3.2
Storage Storage
• Inappropriate design of cooling rooms. • Poor or lack of equipment maintenance and cleaning programmes.• Lack of control of temperature and Relative Humidity conditions.• Lack of control on personnel entrance to the cooling rooms.• Poor or lack of cooling rooms cleaning programmes. • Inappropriate distribution/location of the product inside the cooling room (reducing air circulation).
Associated Hazards: mechanical, physical, biological damages.
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Presentation 3.2
TransportTransportAssociated hazards: chemical,
biological, mechanical damages.
• Bad conditions of the vehicles tents/covers. • Poor cushioning systems of the vehicles. • Inappropriate systems of loading and unloading. • Uncovered vehicles, expose the product to the negative effect of the environmental conditions. • poor control of temperature and relative humidity in the refrigerated transport systems. • Inappropriate systems of packing (p.e. in bulk).
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Presentation 3.2
Definir actores/roles/Expectativas. INNOVATIONS IN THE TRANSPORT
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Presentation 3.2
Definir actores/roles/Expectativas. Loading and unloading systems
efficiency
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Presentation 3.2
Other Post-Other Post-harvest harvest
treatmentstreatments
Definir actores/roles/Expectativas.
Associated hazards: increase product’s susceptibility to
biological, mechanical damages and quality decay.
• Improper handling during treatment application.• Inappropriate application of the treatments (p.e. temperatures above or below the optimum recommended). • Improper RH conditions. • Poor equipment maintenance and cleaning. • Doses above the recommended ones (i.e.. irradiation dosages).
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Presentation 3.2
To protect the product from direct sun light.Quick transport to the packaging.
Minimize delays before pre-cooling. Uniform product’s cooling.
Store the product at optimum temperature conditions .Practice first in first out rotation.Ship to market as soon as possible.
Use refrigerated loading area.Cool truck before loading.Load pallets towards the center of the truck. Avoid delays during transport.Monitor product temperature during transport.
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Presentation 3.2
• There is not a direct relation between a given post-harvest technology efficiency and its cost. Expensive equipment does not always imply high efficiency, and even the best equipment, without proper management may have little utility and poor results. Effective training and supervision of personnel must be an integral part of quality and safety assurance programs.
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Presentation 3.2
Proper product handling during the post-harvest Chain
relies in understanding the factors that affect the quality
and safety of the product, and the different mechanisms to
minimize their impact. Simple handling practices can have
important impact on product quality and safety
maintenance.
Proper harvesting time, avoid direct sun light,
proper handling, proper ventilation, etc.