Postharvest Deterioration All the crops after harvest is also living entity so should be carefully handled Once they are detached from the parent plant they are deprived of the supply of hormones nutrients water etc ID: 935454
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Slide1
WELCOME
Slide2POST-HARVEST DETERIORATION
Slide3Postharvest DeteriorationAll the crops after harvest is also living entity, so should be carefully handled
Once they are detached from the parent plant, they are deprived of the supply of hormones, nutrients, water etc.
These perishables are highly prone to damage
Postharvest deterioration refers to the sets of undesirable biochemical, physiological, physical changes that shortens the shelf life and quality of the commodities and make it unsuitable for the consumption.
Slide4Postharvest deterioration is following typesPhysical
Physiological
Pathological
Entomological
Slide5Physical deteriorationOne of the most common and severe defects of horticultural products
Physical deterioration of fruits and vegetables occur due to inappropriate harvesting and postharvest handling (lesions and browning)
It not only directly affects appearance attributes (skin and flesh ) but also creates sites for pathogen infection and water loss
Physical injury stimulates ethylene production and respiration in plant tissues
That leads to acceleration of senescence
Slide6Refers to injuries in the outer surface or inner part of the produce which shorten shelf life of produce and make unsuited for consumptionInjuries occurs during harvesting, cleaning, packaging, loading, unloading, transport etc.
Freezing injury is a type of physical injury
Freezing point of fruit and vegetable and fruits is usually higher than 0°C
Slide7Freezing injury occurs when ice crystals form in the tissuesCultivars, locations, and growing conditions may affect the freezing point
To be safe side, the highest temperature at which freezing of a specific commodity may occur should be used as the guide for recommending the optimum storage temperature
Slide8physiological deteriorationPhysiological deteriorations are the
abiotic
non-transferable problem arising from the interaction between the commodity and climate
A number of physiological processes occur in the harvested, non processed horticultural product that contributes to deterioration of fruits and vegetables
Slide9What are the physiological process that leads to deterioration of produce?The physiological process which leads to the deterioration of the produce are given below:
Transpiration:
Respiration:
Suffocation:
Growth (Sprouting):
Maturity:
Ripening and Senescence:
Abscission:
Biochemical transformation:
Greening:
Slide10What are the factors affecting physiological deterioration?Physiological deterioration may develop due to various pre-harvest factors or postharvest factors.
Slide11Pre-harvest factors and their role in physiological deteriorationTemperature:
Fruits exposed to sun results in blotchy ripening.
Larger fruits are more susceptible because of lower heat transfer coefficient resulting from their relatively smaller surface to volume ratio.
Blotchy ripening
Sunburn
…
Moisture stress:
Imbalance
in moisture status of soil and outside environment causes cracking of
fruits
Cracking of fruits is severe when water stress is followed by
rainfall
Cracking of litchi, mango and tomato after a long draught followed by rain is a common physiological
problem
Slide13Preharvest factors contd…Mineral nutrition:
Deficiency
or excess of some mineral nutrient causes physiological disorder in some fruits and vegetables
.
Calcium deficiency:
Blossom end rot in tomato,
capsicum, eggplant, squash:
symptoms:
Blossom-end
rot usually begins as a small water-soaked area at the blossom end of the fruit.
As the lesion develops, it enlarges, becomes sunken and turns black and leathery
.
Secondary molds often colonize the affected area, resulting in a dark brown or black appearance.
Slide14Causes of blossom end rot:It is a physiologic disorder associated with a low concentration of calcium in the fruit.Control:
Maintain the soil pH around 6.5
.
Use nitrate nitrogen as the fertilizer nitrogen source.
Ammonical
nitrogen may increase blossom-end rot as excess ammonium ions reduce calcium uptake.
Foliar applications of
calcium.
Slide15Cracking:Cracking of tomato can be either radial or concentric.
Radial
cracking are often the result of rain or excessive watering after a prolonged dry period.
Concentric
cracking is due to calcium deficiency.
Radial cracking concentric cracking
Slide16Spongy tissue of mangoSymptoms: Fruitslook normal
from
outside. But inside, a patch of flesh
becomes
spongy, yellowish and sour
.
It is characterized by unripe, acidic,
pale
yellow to brown corky tissue with or
without
air
pockets.
Causes:
Ca deficiency was a factor of inducing spongy tissue disorder.
When
Ca content was normal, the level of K content was the main factor of inducing disease.
Control:
harvest at ¾ matured rather than fully matured.
Preharvest
spray or postharvest spray of calcium.
Slide17Internal breakdown of mango The disorder, also known as flesh breakdown or internal flesh breakdown, is referred to as jelly seed, soft nose, or stem-end cavity (SEC).
Symptoms:
characterized by
premature
and uneven ripening
of the
mesocarp
.
It
results in watery,
translucent tissue
around the seed giving
an over-ripe
appearance.
Causes:
Ca deficiency
Control:
pre harvest or postharvest spray
of
calcium.
Slide18Bitter pit in appleSymptoms:development of discrete
pitting of the cortical flesh, the pits being
brown and becoming desiccated with time.
The pits may occur predominantly near the
surface or deep in the cortical tissue.
Causes:
calcium deficiency.
Control:
Rapid cooling, CA storage, and application of postharvest calcium drenches may be able to reduce its occurrence.
Preharvest
applications of calcium may be far more effective than postharvest drenching.
Slide19Jonathan spotSymptoms : Sharply sunken area at thelenticel
that is very dark brown or black and
about 1/8 of an inch in diameter.
These spots penetrate the flesh somewhat below the surface of the skin.
Causes:
cause of this disorder is calcium deficiency.
Control:
Harvesting fruits at optimum maturity, prompt cooling, and sharp control of storage temperatures.
Preharvest
or postharvest spray of calcium also reduces this disorder.
Slide20Low temperature breakdownSymptoms:the affected tissues
are more likely to be firmer, more
moist, and darker in color.
Causes:
calcium deficiency.
Control:
preharvest
or postharvest spray of calcium.
Senescent breakdown
Causes:
harvest of
overmature
fruit
with low calcium content.
Control:
drenched with calcium
before storage.
harvesting fruit at a less mature stage
rapid cooling and reducing storage
duration.
Slide21Water coresSymptoms: Intercellular air spaces in the
core and cortical tissues become filled
with liquid, predominantly
sorbitol
.
Causes:
It is associated with advancing fruit maturity and low night temperatures prior to harvest.
Low calcium level also associated with this malady.
Control:
preharvest
or postharvest spray of calcium.
Slide22Boron deficiencyLumpiness in papaya:
Symptoms:
fruits become deformed
And lumpy, and they do not grow to
full size.
Causes:
boron deficiency
Control:
boron spray
Cork spot in pear:
characterized chiefly by a bumpy,
uneven appearance of the pear surface
Affected areas usually have a more
yellow color than the rest of the
surface.
When diseased fruits are peeled or cut,
large masses of brown or grayish
necrotic tissues are seen to underlie
the spots
Slide23Boron deficiency contd…Black head in cauliflower:
Slide24Excess nitrogenStem end rind breakdown of citrus:
symptoms:
It is characterized by the
irregular collapse
and darkening of
rind tissue around the stem end of citrus
fruit. A narrow ring of unaffected tissue immediately around the stem (button) is a distinctive symptom of SERB.
Causes:
pre-harvest imbalance in nitrogen and potassium.
control:
Postharvest practice that minimizes water loss .
coat of wax are currently the best means of reducing SERB.
Use of optimum quantity of nitrogenous fertilizer.
Slide25Exanthema:Symptoms: Exanthema is characterized by dark brown, glossy, gum soaked eruptions occurring as irregular blotches that turn black as the fruit matures.Causes:
This disorder caused by copper deficiency and is aggravated by high nitrogen and
phosphrous
fertilization.
Control:
foliar spray of copper and using appropriate dose of nitrogen.
Slide26Cultural practicesOleocellosis
Symptoms:
It appears as irregularly
shaped green, yellow or brown spots that darken over time and make the glands more prominent.
Causes:
It arises when mechanical damage releases oil from the oil glands. The oil is toxic to surrounding tissue and will inhibit
degreening
of that tissue.
Control:
do not harvest turgid fruit early in the morning, when dew is present, during foggy conditions or immediately after rain or irrigation
Rotting of potato, sweet potato, onion etc are very high if irrigated close to the harvest period.
Slide27Post harvest factorsTemperature
High temperature
: Very high temperature (90-95°F) during ripening of banana causes
weak neck
.
In this case banana easily separate from the bunch, weak neck is usually followed by
neck rotting.
Low temperature
:
Black heart in pineapple:
If pineapple is stored below 10°C they showed the water soaked spot near the core.
At later stage some
fruitlets
turn brown and this is termed as endogenous brown spot or black heart of pineapple.
Chilling injury is the major problem in low temperature storage of the susceptible commodities.
The symptoms of chilling injury vary with the type of tissue involved.
The symptoms of chilling injury normally occur while the produce is at low temperature.
Sometimes the symptoms appear only after produced is held at high temperature, at which the rate of deterioration is very fast.
The injured tissue are more prone to pathological attract which results faster deterioration of the commodity.
Slide29Mechanism of chilling injuryAbnormal respiration rate
According to this hypothesis chilling injury results from disruption of the synchronization of the various stages in the complex respiratory sequence
Not all the reactions are reduced by lower temperature
As some of the reactions are reduced at differential rates than other, there is accumulation of intermediate metabolites, which cause abnormal metabolism, production of off flavor, undesirable volatiles etc.
Slide30Changes in membrane permeability:Membranes of cellular and sub cellular organelle are composed of lipid and protein moleculesDepending on the types of fatty acid involve and nature of combination, the viscosity of membrane is influenced by temperature
At low temperature the change of some lipids from liquid to solid state changes the permeability of membrane and streaming of the substrates is restricted
Cessation of streaming may results metabolic abnormalities such as anaerobic respiration, accumulation of intermediary substrate and undesirable reactions, which ultimately cause chilling injury, and death of the tissue
Plants of tropical and sub tropical origin contain fatty acids than are highly saturated thus they are most susceptible to chilling injury
Slide31Imbalance of tissue distribution of chemical compoundsWithin the fruits also the nature of tissue and chemical composition varies in different portion, thus chilling injury appears in weak and sensitive tissue.Impairment of enzyme activity
The kinetics of enzyme action and synthesis are temperature dependent
Each enzyme has its own temperature optimum for maximum activity
At a given temperature some enzymes are more activate while others are inactivated as a result there is accumulation of intermediary metabolites and development of chilling injury
Slide32Accumulation of toxic metabolitesAs a result of abnormal metabolism there may be accumulation of toxic metabolites which causes damage to the tissue (chilling injury).Factors affecting chilling injury
Maturity:
Variety:
Growing conditions:
Mineral nutrition:
Abrupt change in temperature:
Humidity in storage:
Controlled atmosphere storage:
Slide33LightGreening in potato
Presence of light during storage causes greening of potato, which is a physiological problem.
Greening is associated with the production of alkaloid named as
solanine
.
Greening occurs in eye, peel and sprouts.
Slide34GasesOxygen and carbon dioxide
Self modification of environment in storage and inside packages sometimes causes physiological disorder.
Polybag
storage is common way of packaging fruits and vegetables.
If ventilation is not provided there will be
continous
increase in carbon dioxide and decrease in oxygen.
Lack of oxygen and increased carbon dioxide in storage causes various kinds of physiological disorders.
e.g. striking odor in broccoli, black heart of potato etc.
Slide35Black heart of potatoBlackheart is storage or transportation induced
disorder caused by low O
2
.
Typically, blackheart is induced at > 30 °C
(86 °F), which increases respiration.
If air exchange around tubers is sufficient, low O
2
conditions develop in the interior of the tuber and the cells suffocate and turn black.
Carbon dioxide blocks the pathway of aerobic respiration from
pyruvate
to Acetyl Co A. accumulation of
pyruvate
causes
anerobic
fermentation and produce acetaldehyde (CH
3
CHO) and alcohol (CH
3
CH
2
OH).
Slide36EthyleneIn some commodities ethylene causes abnormalities and deterioration of quality.
Leafy vegetables: chlorophyll breakdown and yellowing
Carrot: production of
isocoumarin
causes bitterness.
Asparagus: toughening of tissue and textural modification
Capsicum: color change
Ammonia
It is commonly used in refrigerator and cold storage.
In some cases leakage of ammonia causes discoloration of stored commodities.
If red onion is exposed to ammonia they will turn greenish black, while white onion will turn gray to brownish black.
Slide37Chilling injury of orange:Symptoms: Chilling injury include pitting, brown staining, increased decay, internal discoloration, red blotch and loss of juice off-flavors, and watery breakdown.
Causes: develop at 5 °C (41 °F) or become evident 1 to 2 days after moving to room temperature (about 72 °F).
Control: The best means of preventing chilling injury is by storing fruit at non-chilling temperatures.
Slide38Creasing (albedo breakdown)Symptoms: Irregular deterioration of
albedo
cells (white spongy tissue) and the collapse of the overlaying
flavedo
(colored portion of the rind) into irregular grooves over the fruit surface.
Such areas are weaker and often split,
providing entry for pathogenic fungi and
subsequent decay.
Common in thin skinned fruits.
Causes: potassium deficiency and is associated with advanced fruit maturity.
Control: earlier fruit harvesting and proper fertilization of potassium fertilizer.
Slide39AsparagusChilling injury
: Asparagus is subject to chilling injury after about 10 days at 0 °C (32 °F).
Symptoms include loss of sheen and glossiness and graying of tips.
A limp, wilted appearance may be observed. Severe chilling injury may result in darkened spots or streaks near the tips.
Elongation and tip bending:
Asparagus continues to grow and elongate after harvest if not cooled immediately and stored at low temperatures < 5 °C (41 °F).
Contacting water at the base will also promote spear growth and elongation.
Tip bending occurs as the result of upward growth of the tips when the spears are horizontal.
Slide40Chilling injury
Elongation and tip bending
Slide41Watery scales of onion: symptoms include thick leathery skin, which when peeled away, reveals watery, glassy, fleshy scales below.Late harvesting and prolonged field drying
produce the highest occurrence of leathery
skin.
Scale greening of onion
Exposure to light after curing causes green coloration of outer scales.
Slide42Feathering or skining of potato:common disorder in early-crop or “new” potatoes (harvested
immature).
Soil drying and vine death enhance skin set,
and thus decrease skinning.
Hollow heart of potato:
it is related to irregular growth, inadequate water availability and/or widely fluctuating temperatures.
Slide43Blotchy ripening of tomato: characterized by the randomizeddevelopment of green or green-
yellowish areas on the surface of red
tomato fruit.
Apparently, the development of
this disorder is related to the availability of low potassium and inorganic nitrogen in the soil system.
Irregular ripening of tomato:
characterized by the appearance of non-uniform ripening
and white internal tissue.
It has been associated with the feeding of
sweetpotato
whitefly on tomato fruit.
Slide44Pathological deterioration30% loss by postharvest pathology only
Fungi, bacteria, are major MO
Disease are high where temp and RH is higher
Pathogens not only produce diseases but also produce ethylene gas and lead to deterioration of commodity at faster rate
Slide45 Practical 1Proposal writing related to Postharvest Horticulture
Format
Introduction
Background
Problem
Rationale of study
Objectives
Broad objective
Specific objectives
Materials and methods
Expected output
Risk
and uncertainty
Innovation
Beneficiaries
Budget
References