Precooling removes the field heat.
Reduction in rate of respiration and ethylene (C2H4) liberation.
Reduction the chance of fungal infection.
Reduction of water loss from the harvested produce.
Prevent quality loss due to softening.
Restriction of the enzyme activities.
Prevent quality loss due to softening.
It reduces energy required for cold storage.
It provide Marketing flexibility.
Fruits play a vital role in human nutrition as well as generate high income to the growers. Pre-harvest and post-harvest factors have a great effect on the postharvest quality of fruits. The combination of these factors includes genetic, environmental, cultural practices, irrigation, packaging, pre-cooling, storage, transportations, etc. In this paper, we provide a review of studies on how pre-harvest and post-harvest factors influence the post quality of fruits. The influence of pre-harvest and post-harvest factors can be controlled by various cultural practices, use of certain chemicals and high tech recent management practices.
Fruits play a vital role in human nutrition as well as generate high income to the growers. Pre-harvest and post-harvest factors have a great effect on the postharvest quality of fruits. The combination of these factors includes genetic, environmental, cultural practices, irrigation, packaging, pre-cooling, storage, transportations, etc. In this paper, we provide a review of studies on how pre-harvest and post-harvest factors influence the post quality of fruits. The influence of pre-harvest and post-harvest factors can be controlled by various cultural practices, use of certain chemicals and high tech recent management practices.
Ginger is obtained from the rhizomes of the plant Zingiber officinale Roso. It originated in
South East Asia and is valued for the dried ginger spice and preserved crystallised ginger.
Chemical treatment - Disinfection of food commodityVikas Tiwari
Succulent nature of fruits and vegetables make them easily invaded by these organisms. The common pathogens causing rots in fruits and vegetables are fungi such as Alternaria, Botrytis, Diplodia, Phomopsis, Rhizopus, Pencillium and Fusarium and among bacteria, Erwinia and Pseudomonas cause extensive damage.
Losses from post-harvest disease in fresh produce can be both quantitative and qualitative. Loss in quantity occurs where deep penetration of decay makes the infected produce unusable. Loss in quality occurs when the disease affects only the surface of produce causing skin blemishes that can lower the commercial value of a crop.
We take pride in introducing over selves as the leading manufacturer & supplier of fruits/vegetables sorting-grading plants and other allied equipments. AGROSAW specializes in the design and the manufacture of sorting, washing, waxing, drying and grading systems for fresh fruit and vegetables. We have complete range of machineries for any type of fruits and vegetables.
However we want to ensure that we guarantee the quality of the equipment and you will definitely get good brand image. We believe that if this cooperation become successful than we will have more opportunities for mutual cooperation.
We are the most trusted supplier for the prestigious companies engaged in Agribusiness and value addition of the product. The AGROSAWTM name today is synonym to quality equipments and latest technology.
The different categories of manufacturing include:
1. Sorting- Washing- Waxing- Drying- Grading of Round Fruits & Vegetables like Oranges, Kinnows, Sweetlime, Tomato, Lemon, Amla etc.
2. Sorting & Grading of Potato, Onion and Garlic.
3. Sorting- Washing- Waxing- Drying- Weight Grading of Mango and other similar fruits like Capsicum etc.
4. Length grading of Carrots, Cucumbers, Radish etc.
5. Manual Sorting-Grading line for oblong shaped vegetables like Ginger, Ladies finger etc.
6. Semi Automatic Net Clipping Machine.
7. Shrink Wrapping Machine.
8. Vacuum Packaging Machine.
9. Onion Topper
10. Baggers.
Powerpoint dealing with the processing of Pepper and Cardamom. It deals with the flowchart involving the processing of these spices. It also deals with the various unit operations involved and the kind of equipment which is used to for the unit operations. it deals with all the processing after harvesting to drying, cleaning, packaging, storage etc of the spices
Factors affecting postharvest storability of fresh fruits and vegetablesJeebit Singh
The presentation in a very brief and concise manner describes various major postharvest factor which affects the storage life of fresh fruits and vegetables and also the fundamentals principles to keep in mind while designing the storage structure or methods to keep fresh produces longer.
Maintenance of market quality from quality loss is vital importance for the success of horticultural industry. After harvest, many horticultural products are susceptible to deterioration and it is necessary to cool them as quick as possible. The process of precooling is the removal of field heat which arrest the deteriorative and senescence processes so as to maintain a high level of quality that ensures customer satisfaction. Different precooling methods employed to cool down the produce includes room cooling, forced-air cooling, hydro-cooling, package icing, vacuum cooling and cryogenic cooling. These methods use different modes and media for their function. Room cooling and forced-air cooling use cold air, hydro-cooling makes use of cold water, package iced products have direct contact with ice, vacuum cooling employs the evaporation of water and cryogenic cooling involves liquid nitrogen. Fruits are normally cooled with cold air, although stone fruits benefit from hydrocooling, while vegetables and flowers may be cooled by employing any of the above-mentioned cooling methods, depending on the physiology and market requirements. So, it has been pointed out that precooling is the most important of all the operations used in the maintenance of any desirable, fresh and saleable produce.
Ginger is obtained from the rhizomes of the plant Zingiber officinale Roso. It originated in
South East Asia and is valued for the dried ginger spice and preserved crystallised ginger.
Chemical treatment - Disinfection of food commodityVikas Tiwari
Succulent nature of fruits and vegetables make them easily invaded by these organisms. The common pathogens causing rots in fruits and vegetables are fungi such as Alternaria, Botrytis, Diplodia, Phomopsis, Rhizopus, Pencillium and Fusarium and among bacteria, Erwinia and Pseudomonas cause extensive damage.
Losses from post-harvest disease in fresh produce can be both quantitative and qualitative. Loss in quantity occurs where deep penetration of decay makes the infected produce unusable. Loss in quality occurs when the disease affects only the surface of produce causing skin blemishes that can lower the commercial value of a crop.
We take pride in introducing over selves as the leading manufacturer & supplier of fruits/vegetables sorting-grading plants and other allied equipments. AGROSAW specializes in the design and the manufacture of sorting, washing, waxing, drying and grading systems for fresh fruit and vegetables. We have complete range of machineries for any type of fruits and vegetables.
However we want to ensure that we guarantee the quality of the equipment and you will definitely get good brand image. We believe that if this cooperation become successful than we will have more opportunities for mutual cooperation.
We are the most trusted supplier for the prestigious companies engaged in Agribusiness and value addition of the product. The AGROSAWTM name today is synonym to quality equipments and latest technology.
The different categories of manufacturing include:
1. Sorting- Washing- Waxing- Drying- Grading of Round Fruits & Vegetables like Oranges, Kinnows, Sweetlime, Tomato, Lemon, Amla etc.
2. Sorting & Grading of Potato, Onion and Garlic.
3. Sorting- Washing- Waxing- Drying- Weight Grading of Mango and other similar fruits like Capsicum etc.
4. Length grading of Carrots, Cucumbers, Radish etc.
5. Manual Sorting-Grading line for oblong shaped vegetables like Ginger, Ladies finger etc.
6. Semi Automatic Net Clipping Machine.
7. Shrink Wrapping Machine.
8. Vacuum Packaging Machine.
9. Onion Topper
10. Baggers.
Powerpoint dealing with the processing of Pepper and Cardamom. It deals with the flowchart involving the processing of these spices. It also deals with the various unit operations involved and the kind of equipment which is used to for the unit operations. it deals with all the processing after harvesting to drying, cleaning, packaging, storage etc of the spices
Factors affecting postharvest storability of fresh fruits and vegetablesJeebit Singh
The presentation in a very brief and concise manner describes various major postharvest factor which affects the storage life of fresh fruits and vegetables and also the fundamentals principles to keep in mind while designing the storage structure or methods to keep fresh produces longer.
Maintenance of market quality from quality loss is vital importance for the success of horticultural industry. After harvest, many horticultural products are susceptible to deterioration and it is necessary to cool them as quick as possible. The process of precooling is the removal of field heat which arrest the deteriorative and senescence processes so as to maintain a high level of quality that ensures customer satisfaction. Different precooling methods employed to cool down the produce includes room cooling, forced-air cooling, hydro-cooling, package icing, vacuum cooling and cryogenic cooling. These methods use different modes and media for their function. Room cooling and forced-air cooling use cold air, hydro-cooling makes use of cold water, package iced products have direct contact with ice, vacuum cooling employs the evaporation of water and cryogenic cooling involves liquid nitrogen. Fruits are normally cooled with cold air, although stone fruits benefit from hydrocooling, while vegetables and flowers may be cooled by employing any of the above-mentioned cooling methods, depending on the physiology and market requirements. So, it has been pointed out that precooling is the most important of all the operations used in the maintenance of any desirable, fresh and saleable produce.
Define the term post harvest ? What are effects of post harvest treatments ?Shahzadinida
Post harvest treatments encompass a range of practices applied to crops after harvesting to preserve quality and prolong shelf life. These methods include cleaning, sorting, cooling, packaging and storage among others.
This PPT about the individual quick freezing of herbs which is semi automated process. gives an idea about IQF and how the freezing of herbs done and their specification
Why Post Harvest Management and cold chain is applied to Perishable produce. Basics of Post harvest care. What packaging is required, what kind of food safety is required, contamination and tainting, HAACP control. Download from www.crosstree.info
Control of pollution by genetically engineered microorganismsSamar Biswas
Pollution refers to the presence of a substance or substances in the environment that are harmful or toxic. The substances or pollutants may be harmful to human health, other animals, and plants. When something harmful enters the environment at a faster rate that it can be dispersed, there is pollution.
PRESENT STATUS AND PROSPECT OF BOTANICALS IN PLANT DISEASE CONTROLSamar Biswas
Botanicals have been in use for a long time for pest control. A product of species coevolution, these compounds offer many environmental advantages. However, their uses during the 20th century have been rather marginal compared with other bio control methods of pests and pathogens. Improvement in our understanding of plant allelochemical mechanisms of activity offer new prospects for using these substances in crop protection. We examine the reasons behind their limited use and the actual crop protection developments involving plant allelochemicals, namely formulations including bio pesticides of plant origin for organic or traditional agricultures, and improvement of plant resistance to pathogens through identification of genes coding for allelochemicals and stimulation of natural passive and active defenses of the plant. Commercial and regulatory aspects are discussed.
FARMERS’ KNOWLEDGE ON ADVERSE EFFECT OF USING AGRO-CHEMICALSSamar Biswas
Agrochemical , a contraction of agricultural chemical, is a generic term for the various chemical products used in agriculture. In most cases, agrichemical refers to the broad range of pesticides, including insecticides, herbicides, and fungicides. It may also include synthetic fertilizers, hormones and other chemical growth agents, and concentrated stores of raw animal manure(Wikipedia).
Chemical fertilizer as an important agro-chemical in Bangladesh was first introduced with limited use in early sixties. Its consumption has increased progressively over the last three decades. Total consumption of fertilizers increased around four folds from 0.87 million tons in 1980-81 to 3.04 million tons in 1996-97 with a growth rate of 8.36% per annum
Today is an established fact that agriculture not industry is major polluter of environment on a local , regional and global basis (Conway and Pretty, 1991).
Postharvest Loss Reduction of Fruits in Bangladesh: Achievements and ChallengesSamar Biswas
A study was done to find the present status, causes of losses and remedies of postharvest loss of fruits in Bangladesh. Farmers are producing huge number of fruits but poor postharvest handling and practices caused about 25-50% losses of fruits in our country. The total loss due to poor postharvest processing of fruits in Bangladesh when valued in monetary terms reflects a tremendous loss in the economy. The gross value of the losses stands at Tk. 6.120 to 8.160 million. Such a situation doesn't only reduce the national income but also leads to malnutrition and socio-economic problems. Main causes of postharvest losses are improper harvesting, packing, excessive and rough handling, poor transportation and storage facilities. Both the government and private sector need to invest much effort in research and extension towards improving and modernizing postharvest facilities for attaining more efficient market infrastructure and distribution channels. Research and extension activities have to be closely coordinated particularly in the public sector for the benefit of farmers, traders and consumers.
Prospects of Hybrid Rice Cultivation in BangladeshSamar Biswas
Rice plays an important role in the economy of Bangladesh. It is by far the most important food crop in Asia. Extension of rice area through increased rice production under irrigated condition is a herculean task. The conventional varieties of rice in Bangladesh are comparatively lower-yield and it seems impossible to change this yield with reachable resources under the prevailing situation. At this stage, hybrid varieties of rice may be a breakthrough, which could overcome perpetual yield stagnancy. To feed ever increasing hungry millions of Bangladesh, there is no option but go for hybrid rice. Therefore, development and introduction of hybrid varieties should get topmost priority especially in irrigated MV rice. The national average yield of rice in Bangladesh is low (2.98 t/ha), while yields of the other rice growing countries of Asia such as, China, Taiwan, Indonesia, and Japan are much higher than that of Bangladesh. Bangladesh has been facing acute shortage of rice for a long time to cope with rapid rise of population. Therefore, it has become indispensable to produce more rice to achieve the goal of self-sufficiency in food. Accordingly, production per unit of land area as well as maximum cropping intensity are crucial factors. Therefore, attempts should be taken to increase the yield per unit area through use of comparatively high yielding varieties. Introduction of hybrid rice is an important step towards augmentation of rice yields. Hybrid rice out yielded the existing conventional High Yielding Varieties (HYVs) by 15- 20% in India, Bangladesh and Vietnam.
USE OF NEEM PRODUCTS FOR THE MANAGEMENT OF INSECT PESTS OF VEGETABLESSamar Biswas
The main focus of the study to highlight the benefit of managing insect pests with neem products, based on the finding of several secondary sources. Insect management by neem is a house hold word but still it is not a common place event. Neem tree, Azadirachta indica; is a medicinal plant. The trees contain many chemical compounds of which neem seed contain much azadirachtin. It possess medium to broad spectrum of action against insects selectively with low mammalian toxicity. Azadirachtin seems to be an "ecdysone blocker. The interferences of the azadirachtin is too insect’s specific against chemoreceptor and endocrine control systems, by which it affect insect growth, feeding and oviposition. Those are so different from the mammalian system that no toxic effects have been found even after application of gram amounts of azadirachtin per kilogram of body weight. When the neem seed oil is correctly formulated its efficiency increases many times, without any adverse effect on our ecology and environment.
Effect of different growth regulators on the growth and yield of oyster mushroomSamar Biswas
The Greek word “Mykes” and Latin word “Fungus” mean mushroom. In a broad sense, mushrooms are fungi, but 6 all fungi are not necessarily considered as mushrooms. The mushroom is simply a fleshy, spore bearing organ of the fungi, and it belongs to either the class Ascomycetes or Basidiomycetes. The vegetative parts of the mushrooms mainly consist of thread like long thin mycelium which under suitable condition forms fruiting bodies or sporocarps. This sporocarp is called mushroom. They are very unlike green plants because they lack chlorophyll and therefore depend on the preformed food for their nutrition (Song, 2004).
Mushrooms production in Bangladesh started in 1979 at Sobhanbag Horticulture Centre, Savar, Dhaka with the technical assistance of Japan and one spawn laboratory and training facility was established to promote mushroom production at that time. Initially paddy straw mushroom was successfully grown. This variety could not be established due to low yield and short shelf life and was shortly replaced by Oyster mushroom.
SALT TOLERANCE IMPROVEMENT OF HORTICULTURAL CROPS THROUGH SEED PRIMINGSamar Biswas
Salinity is one the major abiotic stresses that affect crop production in arid and semiarid areas. Seed germination and seedling growth are the stages most sensitive to salinity. Salt stress causes adverse physiological and biochemical changes in germinating seeds. Various techniques can improve emergence and stand establishment under salt conditions. One of the most frequently utilized is seed priming. The process of seed priming involves prior exposure to an abiotic stress, making a seed more resistant to future exposure. Seed priming stimulates the pre-germination metabolic processes and makes the seed ready for radicle protrusion. It increases the antioxidant system activity and the repair of membranes. These changes promote seed vigor during germination and emergence under salinity stress. There are different type of priming techniques for seed treatment, i.e. hydropriming, halopriming, osmopriming and hormonal priming. Seed priming increases seedling vigour of several horticultural crops. Tomato, cucumber, French marigold, amaranth and hot peper etc. were tested for seed priming at seedling stage and show better result than nonprime seed against salt stress condition. The priming techniques improved seedling vigour, growth and yield of horticultural crops.
Recent Breakthroughs in Genetic EngineeringSamar Biswas
Genetically engineered immune cells are saving the lives of cancer patients.
Precise Gene Editing in Plants.
DNA-editing breakthrough could fix 'broken genes' in the brain, delay ageing and cure incurable diseases
The Genetic engineering could slow aging, reverse blindness.
The genetic engineering that could change humanity.
Chinese researchers have genetically modified a human embryo.
Clean, efficient source of renewable energy (1)
Made from organic waste
Produces methane
Anaerobic digestion (2)
Replaces non-renewable energy
Digested in an airtight container
Alcoholic fermentation, also referred to as, Ethanol fermentation, is a biological process in which sugars such as glucose, fructose, and sucrose are converted into cellular energy and thereby produce ethanol and carbon dioxide as metabolic waste products. Because yeasts perform this conversion in the absence of oxygen ethanol fermentation is classified as anaerobic.
Cleaning refers to chlorine washing of the banana fruit for the removal of undesirable material including latex, chemicals, adhering soil particles along with the microorganisms carried by the soil.
Sorting in banana would refer to removal of overripe, injured, bruised, rotten, diseased, infected and cut fruits.
Grading in banana fruit would refer to categorization of fruits based on number & size of fingers in each hand.
Recent Advances in Transgenic Orchid ProductionSamar Biswas
In Classical breeding techniques, selection process is time consuming.
Manipulation of specific floral traits and other desirable characteristics by conventional sexual hybridization methods is also practically impossible.
In the past decade, researchers have used molecular genetic techniques to revolutionize orchid biotechnology.
Employs gene transformation systems coupled with rapid selection and regeneration methods for the production of new orchid varieties with the desired traits.
Orchid breeding: Recent advances in biotechnologySamar Biswas
This slide related to orchid breeding technique through biotechnological method that used in the recent year for higher scale orchid production with better quality.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
2. Mangoes are juicy stone fruit (drupe) from
numerous species of tropical trees belonging to
the flowering plant genus Mangifera, cultivated
mostly for their edible fruit.
“The king of the fruits,"
mango fruit is one of the
most popular, nutritionally
rich fruits with unique flavor,
fragrance, taste, and heath
promoting qualities, making
it numero-uno among new
functional foods, often
labeled as “super fruits."
3. Additionally, mango peel is also rich in phytonutrients, such as the pigment
antioxidants like carotenoids and polyphenols.
Health benefits of Mango fruit
Mango fruit has been found to protect from colon, breast, leukemia and
prostate cancers.
Mango fruit is rich in pre-biotic dietary fiber, vitamins, minerals, and poly-
phenolic flavonoid antioxidant compounds.
Mango fruit is an excellent source of Vitamin-A and flavonoids like β-
carotene, α-carotene, and β-cryptoxanthin.
Consumption of natural fruits rich in carotenes is known to protect from
lung and oral cavity cancers..
Fresh mango is a good source of potassium. Potassium is an important
component of cell and body fluids that helps controlling heart rate and
blood pressure.
4. Scenario of Postharvest Loss of
Bangladesh
In Bangladesh, The major post-harvest losses of
mango from farmer to local market due to improper
handling, transportation and grading, packaging and
storage.
The losses found at Mohajon, Foria, Arotder, Bepari,
Wholesaler and Local/Supermarket were found 11%,
1%, 5%, 3%, 12% and 2%, respectively.
Total average loss is found as much as 34%.
If 50% loss of mangoes is reduced through
intervention of appropriate technologies during
transportation and storage, the country may save
about Taka 200 cores in a year.
Losses at Mohajon and wholesaler level can be
minimized by precooling techniques.
5. Bangladesh has potentiality to
increase its export of mangoes
through proper postharvest
technology.
The physiological and biochemical
changes during respiration and
transpiration are influenced by
environmental factors like
temperature, ethylene, O2 and CO2
concentration.
In general these biological activities
causes decline in quality of the
produce and limit its shelf life.
Losses due to respiration and
transpiration may be controlled by
precooling.
Mango export potentiality in Bangladesh
6. Why Precooling needed?
Precooling removes the field heat.
Reduction in rate of respiration and ethylene (C2H4)
liberation.
Reduction the chance of fungal infection.
Reduction of water loss from the harvested produce.
Prevent quality loss due to softening.
Restriction of the enzyme activities.
Prevent quality loss due to softening.
It reduces energy required for cold storage.
It provide Marketing flexibility.
7. Cooling temperature 0 – 14°C
Reduce temperatures via
different means
Principle of precooling
of Mango Pre-cooling
techniques
1. Air cooling
– Room cooling
– Forced air cooling
2. Hydro cooling
3. Ice cooling
– Top icing
– Liquid icing
– Individual package icing
4. Vacuum cooling
5. Evaporative cooling
Direct cooling
Heat sink medium,
eg. Cold water ice
and mixture
Heat out
Indirect cooling
Heat sink medium,
eg. Cold air, cold
metal
Heat out
8. Hydrocooling
The flow of chilled water over produce.
Disadvantages
Limited to produce that are not sensitive
to wetting
Not energy efficient (20-40% efficiency)
Critical point
Good water sanitization practice
Proper packaging
Figure : Pictorial View of the
Cold Water Bath
9. Liquid Nitrogen Augmented
(Initial Cool Down) Air cooling
Precooling of mangoes with liquid
nitrogen was carried out in the setup
as shown in. Liquid nitrogen was
employed as the cooling medium only
for the initial cool down of the system
i.e. till the temperature for storage was
achieved (12oC). Once this
temperature was attained, flushing of
liquid nitrogen into the chamber was
stopped and the storage temperature
was thereafter maintained using a
mechanical refrigeration system till
the end of the storage period.
Figure : Pictorial View of
the Lab Scale Cooling Air
Chamber
10. Forced-air cooling
Fan assisted room-cooling.
The fan pulls cool air
through packaged produce
and forces the hot air to
leave the package.
Cooling rate depends on
temperature and the air
flow rate.
75 – 90% more efficient than
room cooling. Fig. Forced-air cooling
Chamber
11. Ice-cooling
• Ice continues to absorb heat as
it melts
• Suitable for
– Produce with high respiration
rate
– Dense product or palletized
packages
• Relatively energy efficient
– 1 lb of ice cool 3 pounds of
produce (85°F to 40°F)
Maintain low temperature during
transportation
Fig. Ice-cooling chamber
12. Vacuum cooling
Vacuum around the produce
causes water to evaporate
rapidly thus reducing the
temperature
Vacuum is created by putting
produce in the metal container.
Then, the air is evacuated
• Disadvantage: wilting (if
overdone)
Hydro vacuum cooling
– Spray water onto the
produce before vacuum process
Fig. Vacuum cooling
chamber
13. Evaporative cooling
Misting/wetting in the
presence of dry air stream
(RH<65%) to cause
evaporation
Effective and inexpensive
means of providing low
temperature & high RH
conditions
Good for warm season
crop such as tomatoes,
pepper, cucumbers or
eggplant
Fig. Evaporative
cooling chamber
14. Conclusion
Mangoe fruits can be precooled with different techniques such as liquid
nitrogen augmentation of a mechanical refrigeration system, hydrocooling,
or air cooling.
These are unique commonly employed precooling techniques.
It was observed that hydrocooling was a faster technique than air cooling,
however liquid nitrogen augmentation helped to reduce the time required
for air cooling by 20%.
The ripening indices like colour development and firmness of the ripened
fruit indicated that the liquid nitrogen augmented precooling system
employed did not adversely affect the ripening of the fruit.
The physicochemical studies such as firmness, retention of aroma indicated
that the precooled fruits were comparable as far as the technique employed
was concerned.
It could be concluded from this study that liquid nitrogen systems can be
successfully used for precooling of mangoes if the design of the system
ensures no direct contact between the fruit and the cryogenic liquid.
