This document discusses various post-harvest techniques to extend the shelf life of fruits, including alternative methods, genetic modification, and risks of GM crops. It describes edible coatings using hydrocolloids, lipids, and composites to act as barriers and reduce moisture loss and microbial growth in fruits. Ethylene inhibitors like AVG, silver ions, and 1-MCP are discussed as ways to delay fruit ripening. The document also outlines potential advantages and ecological risks of genetically modified crops, including increasing yields and reducing pesticide use but also possible risks of allergies, lower biodiversity, and antibiotic resistance.

2. Sri Konda Laxman Telangana State
Horticultural University
College Of Horticulture, Rajendranagar,
Hyderabad.
PP-606 : POST HARVEST PHYSIOLOGY
LECTURE – 8 &9
SUBMITTED TO:
Dr. A. Kiran Kumar
Associate Dean
SUBMITTED BY:
Y. POOJA
RHD/2019-07

3. Out line
 Alternate Post-harvest Methodology and Quality Attributes
 Scope for Genetic Modification of Post-harvest Life of Fruits
 Advantages of Genetically Modified crops
 Ecological Risk Assessment of GM Crops
 Case Studies
 Conclusion

4. Alternate Post-harvest Methodology and Quality Attributes
Genetically modified (GM) crops have many potential
advantages in terms of raising agriculture productivity and reducing
the need for pesticides, the might also pose hazards to human health,
from toxicity & increasing risk of allergies. So we have some
alternative postharvest methods to increase shelf life of fruits.
They are 1. Edible Coatings
2. Ethylene inhibitors
3. Packaging methods

5. Classification of edible coatings

6. Edible Coatings: Edible coatings are defined as the thin layer of
material which can be consumed and provide a barrier to oxygen,
microbes of external source, moisture and solute movement for
food.
Fruits: Edible coated fruits are Orange, Apple, Grapefruit,
Cherry, Papaya, Lemon, Strawberry, Mango, Peach etc. and
fresh-cut Apple, fresh-cut Peach, fresh-cut Pear etc.

7. The edible coatings are mainly divided into three classes; these
are following- .
1. Hydrocolloids: Polysaccharides, proteins and alginate.
2. Lipids: Fatty acids, acryl glycerides and waxes.
3. Composites: Protein/protein, polysaccharides/protein,
lipid/polysaccharides.

8. Hydrocolloids: Hydrocolloids are originated from animals,
vegetables, microbial or synthetic, they are hydrophilic polymers.
They have hydroxyl group and may be polyelectrolytes such as
Alginate, Carrageenan, Pectin, Carboxy Methyl Cellulose,
Xanthan gum and Gum Arabic.
These are Two types: 1. Polysaccharide Based
2. Animal based

9. Hydrocolloids
Polysaccharide-based:
1. The most common
polysaccharides used for edible
coating of fruits and vegetables
are chitosan, starch, alginate,
cellulose, pullulan, carrageenan,
gellan gum etc.
2. Polysaccharides based edible
coatings having poor moisture
barrier properties, it is water
soluble.
3. Its improved mechanical
handling property and additives
carrying capacity.
Protein-Based Edible Coating
1. Protein based edible coatings
are derived from animals and
plants.
2. The plant based protein edible
coating material are milk
protein casein, whey protein,
zein (from maize), gluten
(from wheat), soy protein etc.
3. Animal based protein edible
coating material are egg
albumen, collagen etc.

10. Lipid Based Edible Coating: The lipid based edible coatings are
used from many years for preservation of fruits and vegetables.
They provide shiny and glossy appearance to food.
Ex: Carnauba wax, bee wax, paraffin wax and
mineral or vegetable oil.
Composites Based Edible Coating: Composites or
Multicomponent films and coatings contain combination of
protein, polysaccharides and lipid based material. This is used to
enhance and improve mechanical strength, moisture and gas
barrier properties of edible coatings and films.
According to Han et al. composites are divided into two
categories given below:
1. Bilayer composites
2. Conglomerates

11. Fruits Used Edible Coating
Grape Aloe Vera
Mango Chitosan, Aloevera, Tapico
flour, sago flour, soy protein,
chitosan
Apple Neem oil, Marigold flower
extract, guar gur & Aloe vera
Strawberry Sodium alginate & Calcium
alginate Arabic gum & Arjun
psyllium mucilage
Banana PVA, CMC, Tannin
Orange, Tomato, Mango,
Papaya, Guava,
Mushroom
Cellulose gum
Plum CMC, pectin

12. Applying Methods of Edible Coating: Edible coatings should be
applied on fruits and vegetables by different methods. These
methods are-
1. Dipping
2. Brushing
3. Extrusion
4. Spraying
5. Solvent casting

13.  The dipping method is used widely for applying edible coatings
on fruits and vegetables, in this method Fruits and Vegetables are
dipped in coating solution for 5-30 sec.
 It is easy to apply on mostly fruits. While Brushing method gives
good result, Edible Coatings applied on generally, Beans and
highly perishable Fruits and Vegetables such as strawberry,
berries.
 Other three methods spraying, extrusion and solvent castings are
also used in food industry.
 Extrusion method depends on thermoplastic properties of edible
coatings; it is best technique for applying of EC for industrial
purpose as compared to other methods.

14. Herbal Edible Coatings: A New Concept:
 Herbal edible coating is a new technique for food industry.
It is made from herbs or combination of other edible
coatings and herbs, most common herbs used in Edible
coatings are such as Aloe vera gel, Neem, Lemon grass,
Rosemary, Tulsi and Turmeric. Herbs have antimicrobial
properties, it consists vitamins, antioxidants and essential
minerals.
 As recently Aloe vera gel is widely used in coating on Fruits
and Vegetables, because of its antimicrobial property, it also
reduces loss of moisture and water. Ginger essential oil,
clove bud oil, turmeric neem extract, mint oil, other
essential oil and extracts are also used in edible coating of
Fruits and Vegetables.
 Herbs are natural source of vitamins, minerals, antioxidants,
beneficial for health act as a nutraceutical and medicines.

15. Case Study -1

17. II.Ethylene inhibitors
1. 2-aminoethoxyvinyl glycine (AVG)
2. silver ions (Ag)
3. 1-methylcyclopropene (1-MCP).
AVG is an inhibitor of 1-aminocyclopropane-1-carboxylic
acid (ACC) synthase, a key enzyme involved in ethylene
biosynthesis. Silver and 1-MCP are both inhibitors of the
ethylene receptors. Inhibitor use as well as off-target effects are
described with a focus on ethylene responses in dark-grown
Arabidopsis seedlings.

18. Case Study -2

19. 1-MCP has been shown to greatly delay avocado softening and loss of green color
compared to untreated fruit. The effect of 1-MCP (400 parts per billion, 12 hours) on
the softening and ripening of 'Simmonds' avocado
Don et al, 2003.

20. III. Packaging Methods:
Packaging is one of the viable options to extend the shelf
life of fresh fruits. Several factors like temperature, oxygen,
cultivar, handling, and ethylene and respiration rate influence the
shelf life of fruits. A proper packaging and its gas exchange
design extends the shelf life to a considerable amount of time.
Innovate packaging techniques like modified active packaging,
active and intelligent packaging, use of antimicrobial extends the
shelf life of fruits to a significant amount to time.

21. Active Packaging Systems:
1. Oxygen Scavengers
2. Humidity Absorbers
3. Ethylene Absorbers
4. Carbon Dioxide Emitter
5. Ethanol Emitters
Intelligent Packaging Systems:
1. Time Temperature Indicators (TTIs)
2. Antimicrobial Active Packaging System
3. Oxygen and Carbon Dioxide Indicators

22. Scope for Genetic Modification of Post-harvest Life
of Fruits

23. Genetic engineering extends tremendous scope and opportunities in
fruit production by providing new genotypes for breeding purpose, supply of
healthy and disease free planting material, important in fruit quality, enhancing
shelf life availability of bio pesticides, bio fertilizers etc. integration of specially
desired traits through genetic engineering has been possible in same
horticultural crops.
Recent advancement in molecular biology genetic transformation have
made it possible to identify, isolate and transfer desirable genes from any living
organism to plants.
The introduction or enhancement of desirable traits is traditionally done
by breeding but it is time consuming and not very precise. On the other hand,
genetic engineering creates plants with specific changes in the background of a
proven cultivar without disturbing their genetic constitution. Expression of
undesirable genes can blocked by the application of antisense gene technology
and RNA technology. Genetic transformation provides the means for modifying
horticultural traits in various horticultural crops without altering their
phenotype.
•

24.  Fruits being highly, are important component of human diet but they
poses very short post-harvest shelf life.
 As they ripen they become very soft and more prone to injuries,
which makes them highly perishable. Physiologists and biochemists
attempted to extend shelf life of fruits by (GM) genetically modified
crops.
 Where gene expression of key enzymes responsible for ripening like
PG-ase, EFE and ACC- synthase by means of antisense RNAs.

25. Advantages of Genetically Modified Foods

26. List of Advantages of Genetically Modified Foods
 Insect Resistance: Some GMO foods have been modified to
make them more resistant to insects and other pests.
 Stronger Crops: Another benefit that GM technology is
believed to bring about is that crops can be engineered to
withstand weather extremes and fluctuations, which means
that there will be good quality and sufficient yields even under
a poor or severe weather condition.
 Larger production: It has been easier to raise crops that are
classified as genetically modified because all of their examples
have the stronger ability to resist pests. This attribute helps
farmers with producing greater amounts of crops or foods.

27.  Environmental protection: the increase of GM animals and crops
often requires less time, tools and chemicals, and may help with
reducing greenhouse gas emissions, soil erosion and environmental
pollution.
 Extensive protection for crops: GM foods were created with the
use of genetic engineering a technology that was designed to make
sure crops will never be damaged in a fast rate.
 More nutritive food: According to the Food and Agricultural
Organization of the United Nations, some GM foods have been
engineered to become more nutritious in terms of vitamin or mineral
content.

28.  Decreased Use of Pesticides: It has been proven that genetically
modified crops do not need pesticides to become stronger against
various types of insects or pests that may destroy them.
 More Income: With genetic engineering, farmers will have more
income, which they could spend on important things, such as the
education of their children for example.
 Less Deforestation: To sufficiently feed the growing population of
the world, deforestation is needed. But with genetically modified
animals and crops, the use of this method will be minimized. This
would decrease carbon dioxide in the atmosphere, which would, in
turn, slow global warming.

29.  Decrease in Global Warming: As more plants and crops can be grown and
at more areas, including those that were previously unsuitable for farming,
oxygen in the environment is increased, decreasing the proportion of
carbon dioxide and, in turn, reducing global warming. In fact, British
economists noted in a study that genetically modified crops have made
significant contribution to reducing greenhouse gas emissions by over 10
million tons, which is equivalent to removing 5 million cars from the road
each year. This means that people would not have to give up their vehicles.
 Decrease in Food Prices: Due to higher yield and lower costs, food prices
would go down. As people in poorer countries spend over half of their
income on food alone, this means automatic reduction of poverty.
 New Products: New kinds of crops are being developed to be grown at
extreme climates, such as those present in dry or freezing environments. As
an example, scientists have developed a new type of tomato that grows in
salty soil. Another good discovery in genetic engineering of plants is the
exclusion of the gene responsible for caffeine in coffee beans, creating
decaffeinated coffee beans, which can then be grown naturally.

30. Ecological Risk Assessment of GM Crops

31.  Allergic Reactions: According to research by the Brown University,
resent genetically modified foods can pose significant allergy risks
to people. In some cases, proteins from organisms that you are
allergic to might be added to organisms that you were not originally
allergic to.
 Not 100% Environmental Friendly: Though it is claimed by many
experts that genetically modified foods are safe for the environment,
they actually still contain several kinds of substances that are not yet
proven to be such.
 Lower level of Biodiversity: When we remove a certain pest that is
harmful to crops, we could also be removing a food source for a
certain species.
 Decreased Antibiotic Efficacy: According to the Iowa State
University, some genetically modified foods have antibiotic features
that are built into them, making them resistant or immune to viruses
or diseases or viruses. And when we eat them, these antibiotic
markers will persist in our body and will render actual antibiotic
medications less effective.

32.  Unusual Taste: Genetically modified foods are observed to have
unnatural tastes compared with the ordinary foods that are sold on
the market. This could be the result of the substances that were
added to their composition.
 Not Totally Safe to Eat: It is proven by scientific studies that GMO
foods contain substances that may cause diseases and even death to
several kinds of species in this world, including us humans. For
instance, mice and butterflies cannot survive with these foods.
 Cross pollination: Cross-pollination can cover quite large distances,
where new genes can be included in the offspring of organic,
traditional plants or crops that are miles away. This can result in
difficulty in distinguishing which crop fields are organic and which
are not, posing a problem to the task of properly labeling non-GMO
food products.
 Gene Spilling: Releasing pollen from genetically altered plants into
the wild through the insects and the wind could have dramatic
effects on the ecosystem, though there is yet long-term research to
be done to gauge such impact.

33.  Gene Transfer: Relevant to the previous disadvantage, a constant risk of
genetically modified foods is that an organism’s modified genes may
escape into the wild. Experts warn that genes from commercial crops that
are resistant to herbicides may cross into the wild weed population, thus
creating super-weeds that have become impossible to kill. Conflicts: GMO
foods can cause a lot of issues in the merchants’ daily life. How? These
products might encourage authorities to implement higher tariffs to
merchants, who would be selling them.
 Exploitations: Some countries may use genetic engineering of foods as a
very powerful weapon against their enemies. It is important to note that
some scientists have discovered that these products can kill a lot of
individuals in the world by using harmful diseases.
 Food Supply at Risk: GMO seeds are patented products and, in order to
purchase them, customers have to sign certain agreements for use with the
supplier or creator. As the reliance on these seeds expands around the
world, concerns about food supply and safety also continue to arise.
Furthermore, these seeds structurally identical, and if a problem affects one
of them, a major crop failure can occur.

34. CONCLUSION: Genetically modified foods can potentially solve
many hunger and malnutrition problems in the world as well as health
protect and preserve the environment by increasing yields & reducing
the reliance upon chemical pesticides and herbicides. However it is
important to proceed with caution to avoid unfavourable consequences
for the surrounding & our health.

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