It should be located in the important production areas where demand of quality planning material existing. The ideal soil is deep, fertile, well drained loam which is free from pests and pathogens. The locality should have adequate supply of quality water. The site should be well connected with all means of transportation. It should be in the vicinity of market to get all time supply of fertilizers, pesticide, growth regulators other necessary inputs required for nursery.
The main objective is to get good quality and true to type planting material for own garden. Commercial Nursery: This type of nursery is established to earn money on the investment. Such establishment require large area as well as investment. Based on the Business Wholesale Nursery: In this type of nursery the plants are produced in large number for sale to retail outlets and mostly located in a place where land and labour cost is cheaper. Retail Nursery: This type of nursery located in the town and largely dependent on house owners for its trade. These nurseries also keep goods which is necessary for raising the garden plants.
Landscape Nursery: This type of nursery is located in the populous towns or cities and caters the need of landscape plants of urban people for beautifying their homes and locality. Mail Order Nursery : It is a specialized wholesale nursery where customer order through the catalogue and receive the plants through mail or parcel services.
Based on Time Duration 1. Temporary Nursery : This type of nursery is developed only to fulfil the requirement of the season or a targeted project. The nurseries dedicated to production of seedlings of transplantable vegetables and flower crops are of temporary nature. Permanent Nursery: This type of nursery is placed permanently so as to produce plants continuously. These nurseries have all the permanent features. The permanent nursery has permanent mother plants block.
The work goes on continuously all the year round in this nursery. Based on type of plants produced 1 Fruit Plant Nursery : In this nursery, seedlings and grafts of fruit crops are produced. Plants like geranium, rose, calendula and marigold are propagated and sold. At the same time the durations and type of plants propagated should be finalized. Some of the important points which have effect on success of nursery business are as follows: Selection of site Site is the basic requirement of a nursery.
Qualities of a good site are : Suitable climate Good soil condition Good irrigation facilities Neither shady nor exposed area Sufficient sunlight Near a habitat Good transport facility Care and management Nursery plants require due care and attention after having either emerged from the seeds or have been raised from other sources like rootstock or through tissue culture technique. Generally they are grown in the open field under the protection of Mother Nature where, they should be able to face the local environment.
The commercial nursery grower should ensure suitable conditions necessary for development and growth of the nursery plants. Following necessary practices should be followed in ideal nurseries: Potting of the Seedling: Before planting of sapling in the pots, the pots should be filled up with proper potting mixture. Now-a-days different size of earthen pots or plastic containers are used for propagation. For filling of pots loamy soil, sand and compost can be used in proportion. Sprouted cuttings, bulbs, corms or polythene bag grown plants can be transferred in earthen pots for further growth.
All the necessary precautions are taken before filling the pots and planting of sapling in it. Manuring and Irrigation: Generally sufficient quantity of nutrients is not available in the soil used for seedbed. Hence, well rotten F. Rooted cuttings, layers or grafted plants till they are transferred to the permanent location, require fertilizers. It is recommended that each nursery bed of 10 X 10m area should be given gm of ammonium sulphate, gm of Single super phosphate and gm of Muriate of potash.
Irrigation either in the nursery beds or watering the pots is an important operation. Heavy irrigation should be avoided. Plant Protection Measures: Adoption of plant protection measures, well in advance and in a planned manner is necessary for the efficient raising of nursery plants. For better protection from pest and diseases regular observation is essential.
For its control good sanitation conditions are necessary. These treatments are given for 5 to 30 minutes. Some of the seed treatments are as follows : Disinfection: The infection within the seed is eliminated by use of formaldehyde, hot water or mercuric chloride. Hot water treatment: Dry seeds are placed in hot water having a temperature of 48 0 C — 55 0 C for minutes. Protection : In dry seed treatment organo mercuric and non-mercuric compounds like agallal, aretan-6, and tafasan For this the seeds are shaken within the seed container. While in wet method, the seeds are immersed for certain period in liquid suspension.
Soil treatment: Soil contains harmful fungi, bacteria, nematodes and even weeds seeds, which affect the growth and further development of plant. These can be eliminated by heat, chemical treatment. Drenching of soil with formalin is also practised. Chemical treatment: The chemicals like formaldehyde, methyl bromide, chloropicrin, vapam are used. If diseases like rust, powdery mildew, leaf spot, bacterial blight, yellow vein mosaic are observed, use of Bordeaux mixture, Carbendazime, Redomil can be used.
Tricoderma viridi a bio-fungicide can also be tried out. Weed Control: Weeds compete with plants for food, space and other essentials. So, timely control of weeds is necessary. For weed control weeding, use of cover crops, mulching, use of chemicals weedicides are practiced. Measures against Heat and Cold: The younger seedling is susceptible to strong sun and low temperature.
For example marketing chains where produce is transported from farm to end user with in a short time period, the rate of PH deterioration is of little consequences. However, with the increasing remoteness of production areas from population centers, the time lag from farm to market is considerable. The deliberate storage of certain produce to capture better return adds to this time delay between farm and end user, by extending the marketing periods into times of shorter supply.
Thus a modern marketing chain puts increasing demands on produce and creates the need for the PH techniques that allows retention of quality over an increasingly longer period. Harvest: is a specific and single deliberate action to separates the food stuff with or with out non-edible portion from its growth medium. Postharvest - all the succeeding action after harvest are defined as post-harvest technique. From this period of time all action is enters the process of preparation for final consumption. The field of study that adds to and uses this knowledge in order to develop affordable and effective technologies that minimizes the rate of deterioration is known as post-harvest technology.
Hence thorough understanding of the structure, composition, biochemistry and physiology of horticultural produce is essential for Post- Harvest technologist. Post-harvest Shelf Life Once Harvested, produce are subject to the active process of senescence. Numerous biochemical processes continuously change the original composition of the produce until it becomes unmarketable. These methods usually include a combination of sensory, biochemical, mechanical, and colorimetric optical measurements.
It has direct applications to post-harvest handling in establishing the storage and transport conditions that prolong shelf life. Horticultural produce is biological entity with various physiological activities like transpiration and respiration continuing even after harvesting. This process leads to the bio-chemical breakdown and cause spoilage of the produce.
Spoilage is initiated by enzymes present inside the produce, involvement of microorganism, infestation of insect-pest and invasion of pathogens. By taking care of these factors, products can be stored for longer period. Importance of Post-Harvest Technology in Horticultural Crops 13 Processing - the application of techniques to prevent losses through preservation, processing, packaging, storage and distribution.
The processed foods have now become more of a necessity than a luxury.
Postharvest Management of Horticultural Crops: Practices for Quality Preservation
It has an important role in the conservation and better utilization of fruits and vegetables. It is necessary in order to avoid glut and utilize the surplus during the peak seasons. It is employs modern methods to extend storage life for better distribution and also processing technique to preserve them for utilization in the off season. Problems faced in establishment of processing unit are identified as follows. Every year new crops are being offered for sale in the markets and it demands innovation in the handling methods and study of their quality factors. The process which deals with handling of parts of the plants, such as fruits, vegetables, root crops, spices, foliage and flowers which are often collectively referred to as perishable crops, is called postharvest management.
Perishables are botanically and physiologically very diverse and therefore behave in very different ways and require a variety of different treatments and conditions. Post-harvest handling is the stage of crop production immediately following harvest, including cooling, cleaning, sorting and packing. The instant a crop is removed from the ground, or separated from its parent plant, it begins to deteriorate. Post-harvest treatment largely determines final quality, whether a crop is sold for fresh consumption, or used as an ingredient in a processed food product.
Effective handling decreases post- harvest losses. Keeping the product cool, to avoid moisture loss and slow down undesirable chemical changes 2. Avoiding physical damage such as bruising, delay spoilage. After the harvest, post-harvest processing is usually continued in a packing house. This can be a simple shed, providing shade and running water, or a large-scale, sophisticated, mechanized facility, with conveyor belts, automated sorting and packing stations, walk-in coolers.
In mechanized harvesting, processing may also begin as part of the actual harvest process, with initial cleaning and sorting performed by the harvesting machinery. Post-harvest technology and its sub - disciplines Post-Harvest Technology mate linkage between consumer end users and producers Fruit and Vegetable Grovers.
It also act like. Products as forward linkage and beedback and monetary as backward linkage Fig. Many simple practices have successfully been used to reduce losses and maintain produce quality of horticultural crops in various parts of the world for many years. Post-harvest technology functioning chain There are many interacting steps involved in any post-harvest system. Produce is often handled by many different people, as transported and stored repeatedly between harvest and consumption.
While particular practices and the sequence of operations will vary for each crop, there is a general series of steps in post-harvest handling systems that are often followed.
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PH Loss reduction 2. Value addition 3. Contribution to the Economy 4. Making availability of fruits and vegetables during off seasons 5. Employment generation 7. Adding variety in taste and nutrition 8. Waste utilization 9. Home scale preservation Supply of food to the defense forces To provide quality, nutritious and safe food 2.
However, it has not been widely cultivated because of its sour taste. To develop new equipment and determine their efficiency. Vegetables are Grouped into three Main Categories 1 Seeds and pods - contain natural wax coating. Many legumes 2 Bulbs, roots and tuber - no coating, but tuber has suberisation 3 Flowers, buds, stems and leaves - low shelf life Flowers: They are variations of inflorescence. Basic structure of inflorescence is stem, including pedicel and peduncles, bracts and flowers. Inflorescence is low in carbohydrates compared to fruits. Hence sucrose solution is provided to enhance the vase life of the flowers.
Almost all the cell components of a plant cell are present in these cells too. All fruits and many vegetables being storage organs or sink of the plant are abundant in photosynthates. Difference Between Fruits and Vegetables Fruits Vegetables Generally consumed as raw, not Consumed as cooked during meals during meals.
Possibility of transmitting food poisoning bacteria to consumers. The structures of different commodities i. Fruits, Vegetables and Flowers are shown in Fig. Derivation of some fruits from plant tissue. The letters indicate the tissues that comprise a significant portion of the fruit illustrated: A pedicel, B receptacle, C aril, D endodermal intralocular tissue, E pericarp, F septum, G placental intralocular tissue, H mesocarp, I endocarp, J carpels, K accessory tissue, L peduncle Fig.
Derivation of some vegetables from plant tissue. The letters indicate the principal origins of representative vegetables as follows: A flower bud, B stem sprout, C seeds, D axillary bud, E petiole, F bulb underground bud , G stem tuber, H swollen root, I swollen root tuber, J swollen hypocotyls, K swollen leaf base, L leaf blade, M fruit, N swollen inflorescence, 0 main bud. Examples of variations in the structure of flowers. A bract, B modifications and fusions, in which the labellum is a median modified petal and the column is comprised of fused stamens and pistils, C complete, single whorl of petals, D prominent feature stamens , E spadix plus spathe, F raceme, G head, H umbel, I spike, J panicle, K cyme, L solitary, M corymb Fig.
Cell components their function relevant to postharvest management Components Functions I Cell wall A. Provide structural support to the plants C. These are found in green cells. In the later stages leucoplasts are known as amyloplasts B. It contains various inorganic ions, sugars, amino acids, organics acids, gums, mucilages, tannins, flavonoids, phenolics, pigments and others nitrogenous compounds C. Nucleus D. Ergastic substances Crystal like calcium oxalate, tannins, fats, CHO and proteins are stored in various components of the cell.
Bio chemical constituents which plays an important role in determining the composition and quality of fruits and vegetables are as follows. Moisture plays an important role in fruits and vegetables because many of the nutrients exist in soluble state in them. The higher moisture content makes the fruits, vegetables and flowers more perishable as it is easily vulnerable to attack by microorganisms. Further moisture is lost during the biological activity of these commodities which deteriorates its quality in terms of freshness.
Therefore, retention of the moisture or prevention of loss of moisture is one of the important considerations in planning a storage technique or strategy for extension of shelf life. The actual water content is dependent on the availability of water to the tissue at the time of harvest. Water content of produce will vary during the day if there are fluctuations in temperature. For most produce, it is desirable to harvest when the maximum possible water content is present as these results in a crisp texture. They occur mainly as starches and structural polysaccharides like pectins, celluloses, hemicelluloses.
In many of the fruits and some vegetables the starches and few other polysaccharides undergo conversion into simple sugars like sucrose, glucose and fructose during ripening. These are responsible for sweetness. Small quantities of carbohydrates also occur as organic acids which are responsible for sourness or acidity. The major organic acids found in fruits and vegetable are citric, malic, tartaric, oxalic and pyruvic. Small quantities of bi- and tri- carboxylic acids are also present.
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In fruits and vegetables carbohydrates contribute mainly for its calorific value. Sugars constitutes major carbohydrates in fruits particularly after ripining a SUGARS: Many tropical and sub-tropical fruits contain highest level of sugars. It helps in imparting colour, flavour, appearance and texture to the fruits. Flavour is fundamentally the balance between sugar and acids ratios. Sugar is the primary substrate for respiration and energy. The glycaemic index GI of fruits and vegetables varies from 22 cherries parsnip , Potato and sweet potato - 55 — 60, Bread- 70 b FIBER: Cellulose, hemicelluloses, lignin and pectic substances 3.
Protein: Fruits and vegetables are not an important source of proteins. These proteins are mainly present as enzymes. In most of them it is present as protective cuticle layer on surface. However, nuts contain considerable amount of fats. Generally low fat levels seen in fruits and vegetables make it healthier foods to combat heart related diseases and disorders like hyperlipidaemia.
Minerals: Fruits and vegetables are good sources of minerals. Minerals are essential for growth and development of body right from birth to old age. Calcium is present in several fruits as calcium pectate in cell walls. Calcium appears to be linked to control of enzyme activities, respiration and ethylene production. Some fruits like bananas are rich in potassium.
Vitamins: Generally fruits and vegetables are rich in vitamins but their quantity is varied among them. These are needed for growth, normal function of the body. The sources of different vitamins are given in Table 2. Table 2. Vitamins and their sources Vitamin A Leafy vegetables, radish tops, mango, papaya, carrots etc.
Riboflavin B2 Banana, litchi, papaya, radish top, pineapple, cowpea etc. Niacin B 3 Banana, strawberry, peach, cherry, green vegetables etc. Pigments: The attractive colour of the Mmany fruit is due to sugar derivates of anthocynidins. At the time of ripening, loss of chlorophyll and accompanied by synthesis of anthocyanins or carotenoids which present in vacuole and chloroplast respectively.
Phenolics and antioxidants - major class of plant compounds, it comprising of anthocyanins, leucoanthocyanins, anthoxanthins, hydroxybenzoic acids, glycosides, sugar esters of quinic and shikimic acids, esters of hydroxycinnamic acids and coumarin derivatives. The phenols are impotent in determining the colour and flavour of the fruit. Phenols are by products of the metabolism of the amino acids and contribute the sensory qualities of the fruits colour, astringency, bitterness and aroma and play the vital role in the resistance to attack of pathogen and stress.
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It is known for its antioxidant activities. Structure and Composition of Fruits, Vegetables and Flowers 25 9. Organic acids - Imparts taste and flavour. The major acids are malic apple , citric citrus , tartaric grape , quinic, succinic and shikimic acids Organic acids plays important role in— Photosynthesis and respiration — Synthesis of phenolic com- pounds, lipids and volatiles aroma Volatiles Flavour compounds -Important in producing characteristic flavor and aroma mol.
Compounds are - esters, alcohols, acids, aldehydes and ketones. Ethanol is common to all Fruit and Vegetables, where as others are specific. Esters present in ripe fruits, Sulphur in Brassica sp. Texture - Texture is governed by structural polysaccharides. While attached to plants, losses due to transpiration and respiration are replaced by flow of sap, which contain water, photosynthates and minerals. These functions continue even after harvest, and since the produce is now removed from the its normal source of H2O, photosynthates and minerals, the produce entirely depend on their own food reserves and moisture content.
Therefore, losses of repairable substrates and moisture are not made up and deterioration has commenced hence, produce are perishable. They have the typical plant cell system. The life of fruit and vegetables can be conveniently divided into three major physiological stages following germination. Growth and maturation are often collectively referred to as the development phase. Ripening occur during the later stages of maturation and is the first stage of senescence. Normally development and maturation processes are completed before harvest.
But depending upon the nature of produce and the desired characteristics in a particular fruit or vegetable, the maturity stage differs. Similar terminology may be applied to the vegetables, ornamental and flowers, except that ripening stages does not occur. As consequence it is very difficult to delineate the changes from maturation to senescence in vegetables and ornamentals. Vegetables are harvested over a wide range of physiological ages, that is, from a time well before the commencement of maturation through to the commencement of senescence.
Fruit Respiration One of the major physiological and biochemical change which occur in fruits and vegetables is a change in the pattern of respiration Fig. The respiration rate of produce is an excellent indicator of the metabolic activity of the tissue and thus is a useful guide to the potential storage life of the produce. The respiratory pattern also impacts the pattern of evolution of ethylene.
Few fruits exhibit the pronounced increase in the respiration increase in CO2 and C2H4 coincident with the ripening, such increase in the respiration is known as respiratory climacteric, and this group of fruits is called climacteric Fig. Ripen on the plant itself. The quality of fruit changes drastically The quality do not change significantly after harvest characterized by after harvest except little softening. Do softening, change in colour and not change to improve their eating sweetness.
Growth, Respiration and Ethylene Production Pattern of climacteric and non- climacteric plant organs Fig. Maturity in relation to developmental stages of the plant Respiration Respiration is a process in which stored organic materials carbohydrates, protein, and fat are broken down into simple end products with release of energy. Oxygen is used in this process and carbon dioxide with loss of water is produced. This ratio between the oxygen consumed and carbondioxide produced is called respiratory quotient.
This relationship is important in measuring respiration by gas exchange. Respiration influences the product in following manner l Reduced food value energy value for the consumer l Reduced flavor due to loss of volatiles l Reduced sweetness l Reduce weight l Important for the commodities desire dehydration The rate of deterioration of horticultural commodities is directly proportion to the respiration rate.
On the basis of their respiration rate we can classify different fruit and vegetables is in Table 3. Table 3. Temperature 2. RH Relative Humidity 3. Gas composition in the ambient and within the cell 4. Moisture content of the tissue 5. Wounding or injury 6. Type of the plant parts 7. Stage of development of tissue 8. Surface area to volume of the produce 9. Pre-harvest treatments and Post-Harvest methods employed Chemical composition of tissue Size of the produce Presence of natural coating on the surface Ethylene - Its Role, Biosynthesis and Effects Ethylene is a natural plant hormone released by all plant tissues and microorganisms.
Low concentration of 0. It has autocatalytic activity because of which such small quantities can trigger further release of large quantities of ethylene by the fruit tissue. Very little response is only seen to exogenous application of ethylene in case of non- climacteric fruits. Production of ethylene results in premature ripening of certain horticultural produce Fig. All fruits produce minute quantity of ethylene during development, however, coincident with ripening, climacteric fruits produce much larger amount of ethylene than non climacteric fruits.
Physiology and Biochemistry of Horticultural Produce 33 Ethylene Biosynthesis Reaction sequences in the metabolism of ethylene and its action Fig. Ethylene Biosynthesis Ethylene has been shown to be produced from methionine via a intermediates S-adenosyl-methionine SAM and 1-aminocyclopropane carboxylic acid ACC. ACO is a liable enzyme and sensitive to oxygen and attached to outer layer of the plasmalemma. Factor that effect the activity of the ACS includes fruit ripening, senescence, auxin, physical injuries and chilling injury.
ACO is inhibited by anaerobiosis, temperature above 35oC and cobalt ions. Among various chemical used for extension of shelf life fruits 1-MCP has been found to be very effective. Many fruits respond to 1-MCP in extension of storage life by retarding the process of ripening. The pattern of C2H4 production in tomato is it rises before the onset of ripening, where as in, apple and mango it does not rise before increase in reparation. Immature tomato fruit has high rate of C2H4 production and it extremely tolerance to C2H4 but banana and melons can readily ripened with C2H4 even when immature Fig.
On the basis of ethylene production rate herticultural commodities are classified in five groups Table 3. On the basis of ethylene production rate horticultural commodities are classified into following way. Bio chemical changes that occur during the ripening of fruit Events Quality Parameters 1. Seed maturation 2.
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Change in pigmentation Colour Degradation of chlorophyll Unmasking of existing pigments Synthesis caroteniod Synthesis anthocyanin 3. Softening Texture Change in pectin composition Changes in other cell wall composition Hydrolysis of storage materials 4. Change in carbohydrates composition Flavour Starch conversion to sugars Sugar conversion to starch 5. Production of aromatic volatiles 6.
Changes in organic acids 7. Fruit abscission Dropping 8. Change in repatriation rate 9. Change in rate of C2H4 synthesis Ripening Change in tissue permeability Softening Change in proteins Quantitative Qualitative - enzymes synthesis Development of surface waxes Shining Colour Development in Fruit The change in colour is either due to synthesis of plant pigments or due to unmasking of already existing colour. Change in colour is due to chlorophyll, which is magnesium organic complex. The loss of green colour is due to degradation of chlorophyll structure.
Change in colour development is common except avocado, kiwi fruit and Granny Smith Apple. Carotenoids are stable pigments and remain there till senescence. They are either synthesized during developmental process or they are masked by the presence of chlorophyll. This kind of change is seen in case of banana. While in tomato, the colour pigment lycopene is developed simultaneously with degradation of chlorophyll. Other pigments found in fruits and vegetables are anthocyanins.
They are red-purple or blue water soluble phenolic glucosides that are found in vacuoles like in beet root and epidermal cell of apple and grape. They produce strong colour, which often mask carotenoids and chlorophyll. In acidic pH levels the anthocyanins are red in colour and in alkaline pH they tend to become blue. This is due to depletion of CHO and release of free amino acids resulting in more alkaline pH in the cell sap.
Changes in texture and taste: on ripening of fruits, breakdown of starch to sugars, which affects taste and texture of the produce. Textural Changes: The texture of the fruit softens with ripening. This is because of the action of enzymes like hydrolases poly galacturonase, pectin methyl esterase and cellulases which breakdown the pectins, cellulose and hemicellulose. Propectin is insoluble form of pectic substances binds to calcium and sugars in the cell wall.
On maturation and ripening, propectin gradually broken-down to lower molecular weight fraction which are more soluble in water. The rate of degradation of pectic substances is directly correlated with rate of softening of the fruit. Change in Taste: The primary change in taste is the development of sweetness in fruits after ripening. During ripening the starch break down into simple sugars like glucose, fructose and sucrose which are responsible for sweetness.
This change is also mediated through the action of various enzymes like amylase, invertase, phosphorylase, etc. Physiology and Biochemistry of Horticultural Produce 37 Changes in Vegetables Seeds are consumed as fresh vegetables, for eg. Sweet corn baby corn , have high levels of metabolic activity, because they are harvested at immature stage. Eating quality is determined by falvor and texture, not by physiological age. Generally seeds are sweeter and tender at an immature stage.
With advancing maturity, the sugars are converted to starch, with a result of loss of sweetness, water content also decreases and amount of fiber material increases. The natural falvour is often less important than texture, as many of these vegetables are cooked and seasoned with salt and spices. Therefore, they are more perishable when compared to other agricultural commodities. The deterioration in harvested fresh produce occurs both quantitatively and qualitatively. The losses that occur from the time of harvesting of fresh produce till they reach the consumer are referred as post-harvest losses.
Post-harvest losses occur in terms of 1. Quantitative loss - referring to the reduction in weight due to moisture loss and loss of dry matter by respiration 2. Qualitative loss - referring to freshness deterioration leading to loss of consumer appeal and nutritional loss including loss in vitamins, minerals, sugars, etc. Cost of preventing losses after harvest in general is less than cost of producing a similar additional amount of produce and reduction in these losses is a complimentary means for increasing production.
These losses could be minimized to a large extent by following proper pre-harvest treatments, harvesting at right maturity stage and adopting proper harvesting, handling, packing, transportation and storage techniques. The factors that are responsible for the deterioration of Horticultural produce are: I. Biological factors II. Biological Factors Following biological factors are responsible for deterioration of Horticultural Produce: 1.
Respiration rate 2. Ethylene production 3. Compositional changes 4. Growth and development 5. Transpiration 6. Physiological breakdown 7. Physical damage 8. Pathological breakdown 9. Surface area to volume Membrane permeability 1. Respiration rate: Being living entities fruits, vegetables, flowers respire actively after harvest. Since the products are still alive after harvest, their living cells respire to secure energy.
The equation for respiration is as follows. The rate of respiration is again influenced by no of factors during storage. These factors are divided into two groups. A Plant factors B Environmental factors. Plant Factors: a Soluble Sugars: Soluble sugars particularly glucose are chief sugars used in respiration. Hence, the greater the concentration of soluble sugars within the living tissues, the greater is the rate of respiration.
Respiration liberation the necessary energy. So the rate of respiration will be directly proportional to the number of living cells. Generally succulent products respire more rapidly than non-succulent products. Thus lettuce heads respire deteriorate more rapidly than potatoes or sweet potatoes or even peppers. Ethylene production: All the living cells are capable of producing ethylene. Moreover, ripening fruits are rich source of ethylene production.
The cuticle on fruit surface acts as a resistant barrier through which it is dissipated. This is one of the reasons, due to which internal concentration of ethylene with in the fruit is greater than the external concentration in atmosphere. Ethylene causes degreening in oranges and banana, it bleaches green colour of leafy vegetables, celery, cabbage, broccoli etc. In fruits and vegetables degreening related to ripening process. The most obvious and studies effect of ethylene is an initiator of fruit ripening or, as contributor to ripening.
Compositional changes: Many pigment changes also takes place even after harvest in some commodities. These changes are: I. Loss of chlorophyll green color - In vegetables II. Loss of carotenoids yellow and orange color - In apricot, peaches, citrus fruits and tomato III. Loss of anthocyanins red and blue color - In apples, cherries and strawberries IV. Change in carbohydrates V. Sugar to starch conversion - peas, sweet corn b.
Breakdown of pectin and other polysaccharides - causes softening of fruit VI. Change in organic acids, proteins, amino acids and lipids. Loss in vitamins - effects nutritional quality 4. Growth and development: In some commodity growth and development continue even after harvest which accelerates deterioration. For example l Sprouting of potato, onion and garlic l Fresh rooting of onions l Harvested corps continues to grows even after harvest but is very much evident in Asparagus l Increase of volume in lettuce 5.
Transpiration is a physical process in which high amount of water is lost from the produce, which is the main cause of deterioration. This exchange of water vapour in produce is carried through the cuticle, epidermis cells, stomata and hairs of the produce. Produce stored at high temperature will have high transpiration rate. Water loss also causes loss in quality, such as reduced crispness and other undesirable changes in colour, palatability and loss of nutritional quality. Factors influence the transpiration rate in various commodities: I.
Plant factors a. Differentiation of tissues: Plant products differ in the degree of differentiation of their tissues and hence they differ in the rate of transpiration under the same conditions. In general, non- differentiated very succulent tissues contain more water than highly differentiated, non-succulent tissues. Under the same conditions tissues with high water content lose water more rapidly than tissues with low water content.
Ex: Highly succulent - Asparagus spears, spinach leaves highly differentiated products- mature cabbage heads, onions, celery etc. Surface of the commodity: commodities having greater surface area in relation to their weight will lose water more rapidly. It is clearly visible in leafy vegetables where the water loss is much faster than a fruit as they have more surface area to volume ratio.
Surface injuries: Mechanical damages accelerate the rate of water loss from the harvested produce. Bruising and abrasion injuries will damage the protective surface layer and directly expose the underlying tissues to the atmosphere allowing greater transpiration. Skin texture: Fresh produce having thin skin with many more spores lose water quickly than those having thick skin with fewer spores.
Environmental Factors a. Temperature: Water loss is high with increase in storage temperature. The loss will be further enhanced when high temperature is combined with low relative humidity b. Relative humidity: The rate at which water is lost from fresh produce also depends on the water vapour pressure difference between the produce and the surrounding air. So water loss from fresh produce will be low when the relative humidity i. Further, the faster the surrounding air moves over fresh produce the quicker will be the water loss.
Transpiration results in following type of deterioration: - Loss in weight - Loss in appearance wilting and shriveling - Textural quality softening, loss of crispiness and juiciness 6. Physiological breakdown: When produce is exposed to an undesirable temperature physiological breakdown takes place. It causes defects like sunburn, bleaching, scalding, uneven ripening and excessive softening. Pathological breakdown: This is the most common symptom of deterioration where it is mainly caused by the activities of bacteria and fungi yeast and mould.
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, Ervina and Pseudomonas cause extensive damage Microorganisms usually directly consume small amounts of the food but they damage the produce to the point that it becomes unacceptable because of rotting or other defects. 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 value of a commercial crop. Surface area to volume- Grater surface leads to greater weight and respiratory loss Membrane permeability- Fluctuation in storage temperature and physiological injuries like chilling injury leads to membrane damage resulting in electrolyte leakage. Environmental Factors Following environmental factors are responsible for deterioration 1.
Relative humidity 3. Atmospheric gas compositions 4. Ethylene 5. Light 6. Other factors 1. Temperature: Environmental temperature plays very major role in deterioration of produce. Relative humidity: The rate of loss of water from fruit, vegetables and flowers depends upon the vapor pressure deficit between the surrounding ambient air, which is influenced by temperature and relative humidity.
The rate of deterioration is a combined factor of temperature and relative humidity and affects the produce in following manner: l Low Temp. Atmospheric gas composition: Buildup of undesirably high carbon dioxide and very low levels of oxygen in the storage facility can lead to many physiological disorders leading to spoilage.
Hollow heart disease in potato is due to faulty oxygen balance in storage or during transportation. The other bad effects of unfavourable gas composition include irregular ripening of certain fruits, soft texture, lack of characteristic aroma, poor skin color development, etc. Ethylene: Effect of ethylene on harvested horticulture commodities may be desirable or undesirable.
On one hand ethylene can be used to promote faster and more uniform ripening of fruits. On other hand exposure to ethylene can deteriorate the quality of certain vegetables such as destruction of green colour in leafy and other vegetables, early senescence of flowers, bitterness in carrots, increased toughness, accelerated softening, discoloration and off-flavor, etc. Light: Exposure of potatoes to light results in greening of the tuber due to formation of chlorophyll and solanine which is toxic to human on consumption.
Other factors: Various kinds of chemicals eg. Many of the chemical constituents present in stored commodities spontaneously react causing loss of color, flavor, texture and nutritional value. Further there can also be accidental or deliberate contamination of food with harmful chemicals such as pesticides or lubricating oils. Defects Damage No. Insect pests Holes and mis-shapen 2. Nutritional deficiency Dry circular crevices 4. Improper cultural Green spot potato practices 5. Handling Black edges, handling damage, packing damage, pressure damage, shatter or loose berry, damage, soft, bruises and broken 9.
Mechanical means Healed dark brown marks, chipped, hole, punctured skin, cuts, mechanical damage Physiological disorders B itter pit, puffiness, cracking Improper cold storage Dried b erries, sprouting, hollow heart Like one which occur before harvesting and other which develops after harvesting. Some defects however are common to both the categories. Pre-Harvest Factors II. Harvest Factors III. Post-Harvest Factors I. Pre Harvest Factors 1. Light 3. Temperature 4. Humidity 5. Mineral nutrition 6. Canopy manipulation 8.
Rainfall 9. Carbon dioxide Use of agrochemicals Root stock, pruning and crop rotation Pest and diseases II. Harvest Factors 1. Stage of harvest 2. Time of harvest 3. Methods of harvest III. Post - Harvest Factors 1. Humidity 4. Water quality 5. Ethylene 6. Preservatives 8. Growth regulators I.
Varieties with thick peel, high firmness, low respiration rate and low ethylene production rates would usually have longer storage life. The cultivars that have ability to withstand the rigors of marketing and distribution will have lesser losses after harvest. Hence, while growing horticultural crops, one must choose such varieties that inherently have got good quality and storage potential in addition to the high yield and pest resistance potential.
Light: Light regulates several physiological processes like chlorophyll synthesis, phototropism, respiration and stomatal opening.
Most of the produce needs high light intensity f. Absorption of red light nm through pigments, phytochrome, is essential for carbohydrates synthesis which determines the shelf life of the produce. The vase life of the carnation and chrysanthemums is longer under high light intensity than low. Citrus and mango fruits produced in full sun generally had a thinner skin, a lower weight, low juice content and lower acidity but a higher TSS.
And citrus fruits grown in the shade may be less susceptible to chilling injury when subsequently stored in cold storage. In tomatoes, leaf shading of fruits produced a deeper red colour during the ripening than in the case of those exposed to light. The side of the fruit that have been exposed to sun will generally firmer than the non- exposed side. In general, the lower the light intensity the lower the ascorbic acid content of plant tissues. In leafy vegetables, leaves are larger and thinner under condition of low light intensity.
Temperature: All type of physiological and biochemical process related to plant growth and yield are influenced by the temperature. The higher temperature during field conditions decreases life and quality of the produce. At high temperature, stored carbohydrates of fruits, vegetables and flowers are quickly depleted during respiration and plant respires at the faster rate. For example- high temperature during fruiting season of tomato leads to quick ripening of fruits on and off the plant. Orange grown in the tropics tend to have higher sugars and TSS than those grown sub tropics.
However, tropical grown oranges tend to be green in colour and peel less easily and it is due to the lower diurnal temperature that occurs in the tropics. Humidity: High humidity during growing season results in thin rind and increased size in some horticultural produce and this produce is more prone to high incidence of disease during post-harvest period.
Humid atmosphere may cause the development of fungal and bacterial diseases, which damages produce during storage and transport. Low humidity may cause browning of leaf edge on plants with thin leaves or leaflets. Reduced transpiration leads to calcium and other elemental deficiency. Rainfall: Rainfall affects water supply to the plant and influences the composition of the harvested plant part. This affects its susceptibility to mechanical damage and decay during subsequent harvesting and handling operations. On the other hand, excess water supply to plants results in cracking of fruits such as cherries, plums, and tomatoes.
Supply Chain Management of Horticultural Crops | SpringerLink
If root and bulb crops are harvested during heavy rainfall, the storage losses will be higher. Wind: Wind damages the produce by causing abrasions due to rubbing against twigs or thorns. These mechanically damaged produce are more prone to spoilage during post-harvest period and have shorter post-harvest life. Mineral nutrition: Balanced application of all nutrient elements is necessary for the maintaining growth and development of the plants. The application of fertilizers to crops influences their post-harvest respiration rate.
Excess or deficiency of certain elements can affect crop quality and its post-harvest life. Numerous physiological disorders are also associated with mineral deficiencies which ultimately lead to post-harvest losses. Nitrogen: High N fertilization reduces while moderate to high K improves Post-Harvest life and quality of anthurium, cut flowers and many horticultural produce. Application of K in water melon tend to decrease the Post-Harvest respiration. High levels on N tend to decrease flavor, TSS, firmness and color of the fruit and in stone fruits it increases physiological disorders and decrease fruit colour.
Generally, crops that have high levels of nitrogen typically have poorer keeping qualities than those with lower levels as. High nitrogen increases fruit respiration, faster tissue deterioration thereby reducing their storage life. Phosphorous: Application of phosphorous minimizes weight loss, sprouting and rotting in bulb crops compared with lesser application. Phosphorous nutrition can alter the post-harvest physiology of some produce by affecting membrane lipid chemistry, membrane integrity and respiratory metabolism.
The respiration rate of low-phosphorous fruits will be higher than that of high phosphorous fruits during storage. Potassium: Potassic fertilizers improves keeping quality, its deficiency can bring about abnormal ripening of fruits and vegetables. Potassium helps in reducing some physiological storage disorders, e.
Calcium: the storage potential of the fruits is largely dependent on the level of Ca and it is associated with produce texture. The higher level of N, P and Mg and low levels of K and Bo lead to the Ca deficiency in fruits and reduce its storage life. Reduction in calcium uptake causes lateral stem breakage of poinsettia. Calcium treatment delays ripening, senescence, reduces susceptibility to chilling injury, increase firmness and reduces decay subsequent to storage in avocados and improves the quality.
Physiological disorders of storage organs related to low Ca content of the tissue are — Bitter pit in apples Table 5. Zn is known to act as vehicle for carrying ions across tissue and increase Ca content of the fruit. Adequate supply of Bo improves the mobility of Ca in the leaves and the fruits and subsequently increases fruit firmness, TSS, organic acids and reduce the incidence of the drought spot, bitter pit and cracking disorders. And impart diseases resistance. Post climacteric respiration of apple decreased as peel Ca level increased from to ppm.
Ca may reduce the endogenous substrate catabolism by limiting the diffusion of substrate from vacuole to the respiratory enzymes in the cytoplasm limited membrane permeability. Table 5. In pears reduced cork spot, increased flesh firmness, total acidity and juiciness and in apple even after 90 day of storage at ambient condition shown acceptable quality.
Water relation and Irrigation: stress due to excessive or inadequate water in the medium reduce the longevity of the produce. Crop like carnation require to g of water to produce one gram of dry matter. Higher level of moisture stress affects both yield and quality by decreasing cell enlargement. Crops which have higher moisture content generally have poorer storage characteristics. An example of this is the hybrid onions, which tend to give high yield of bulbs with low dry matter content but which have only a very short storage life.
In green leafy vegetables, too much rain or irrigation can results in the leaves becoming harder and brittle, which can make them more susceptible to damage and decay during handling and transport. Mango hot water treatment is better if there is delay of 48 hr. Generally, crops that have higher moisture content or low dry matter content have poorer storage characteristics. Keeping quality of bulb crops like onion and garlic will be poor if irrigation is not stopped before three weeks of harvesting. Canopy Manipulation: a. Fruit thinning: Increases fruit size but reduces total yield.
It helps in obtaining better quality produce b. Fruit position in the tree: Fruits which are exposed to high light environment possesses higher TSS, acidity, fruit size, aroma, and shelf life compared to which lies inside the canopy. Hence better training system should be practiced to circulate optimum light and air. Girdling: increases the fruit size and advance and synchronized fruit maturity in peach and nectarines. Increases fruitfulness in many fruit tree species. Synthesis of higher amount of carbohydrates during the day time and its utilization through translocation and respiration in the night is responsible for the variation in the longevity of the cut flowers.
Roses and tuberose have been found to show longer keeping quality in the winter season under ambient condition than in the summer seasons. Generally produce harvested early in the morning or in the evening hours exhibits longer Post-Harvest life than produce harvested during hot time of the day. Day length - If long days Onion temperate grown during short day tropics condition it leads to very poor storage quality.
Carbon dioxide: quality planting material, early flowering, more flowering, increased yield and rapid crop growth and development at higher level of CO2. Production of chrysanthemum under green house at - ppm of CO2 showed an increase in stem length, fresh weight, leaf no. Application of GA3 ppm improves Post- Harvest quality of roses by anthocyanin development. And it stimulate the accumulation of N, K, Mg and S.
Pre-harvest spray with Alar ppm , MH ppm , and Cycocel ppm increased vase life of aster. Beneficial effect of leaf manure, K and GA3 is found to enhance the longevity of tuberose flowers.
Use of chemicals on the plants to prevent the pathogen will have direct impact on extending the postharvest life. Generally, if produce has suffered an infection during development its storage or marketable life may be adversely affected. Banana which suffers a severe infection with diseases such as leaf spot may ripen pre maturely or abnormally after harvest and in mango it is rapid postharvest loss.
Pre harvest application chemicals like Mellic Hydrazide on onion filed prevent them sprouting during storage. Pest and Diseases: infection by fungi, bacteria, mites and insects reduces the longevity as well as consumer acceptability. The potato tuber moth may infest tubers during growth if they are exposed above the soil and subsequently in the storage. Pre-harvest Factors Affecting the Quality of Fruits and Vegetables The factors affecting the quality of fruits and vegetables can be grouped into environmental and cultural.
Environmental factors Sr. Factors Quality affected No. High temperature reduces the quality, e. Low temperature cause chilling and freezing injury. Exposed fruit to sun light develop the lighter weight, thinner peel, lower juice and acids and higher TSS than shaded fruits, e. Exposure of potato to light causes Greening solanine formation which has toxic properties. High sun light intensity causes Sunscald in citrus and tomatoes and reduces the pure white colour of cauliflower. Low light intensity causes thin and large leaves in leafy vegetables. It reduces appearance and sweetness.
Cultural factors Sr. I Mineral nutrition 1. Its deficiency reduces size of fruits. Phosphorous High phosphorous decreases size, weight, vitamin C e. Its deficiency causes poor appearance of fruit. Potassium Increase size, weight and vitamin C, e. Its deficiency causes uneven ripening. Calcium Increases firmness of many fruits, e. Magnesium Increases size, weight and vitamin C, e. Zinc Increases size, weight and vitamin C, e.
Deficiency causes straggled cluster in Grape. Boron Deficiency causes flesh browning in fruits, e. Fruits and vegetables become hard and misshapen. Cabbage, Turnip and cauliflower are sensitive to boron deficiency. Copper Deficiency causes irregular blotch on citrus fruits and spoils the appearance. II Growth Regulators 1. Gibberlic acid Increases size and weight of grape berries, apricot, and strawberry and causes parthenocarpic fruits in fig, guava, grape, tomatoes etc.
It reduces disorder of fruits, e. Cytokinin Maintain green colourof leafy vegetables and causes parthenocarpic fruits in fig. Ethylene Ethephon increases anthocyanin coloured grape, plum, apple, chillies, brinjal , carotenoides mango, guava, papaya, citrus, tomato etc , ascorbic acid and TSS and reduces tannin grapes, dates, etc and acidity grape, mango, tomato, etc.
Table] Sr. Growth retardant Alar Bg increases colourin fruits, e. Maleic hydrazide MH inhibits sprouting in onion bulbs. III Root stock In citrus Troyer and Carizzo Citranges rootstock produce the fruit of excellent quality of oranges, mandarins and lemons. In guava P. V Pruning It affects the size, colour, acidity and sugar content of grape, phalsa, ber, peach, apple etc. VI Thinning Thinning in grapes, dates, peaches, plum, etc. VII Girdling In grapes, it increases size, colour and sugar content of the berries.
High yield, bright appearance and good shipping qualities are most important characters of the varieties. IX Diseases and pests Both are harmful to fruits and vegetables. X Pesticide Pesticide spray residues may give rise to flavor taints in the processed product. Excessive use of pesticides may even produce harmful metabolites and toxicity not necessarily destroyed during processing.
XI Maturity In general vegetables with exception of potato and onion are of higher quality when less mature because they are more tender, succulent, less fibrous or starchy. On the other hand fruits when ripe are of higher quality on account of full size, bright colour, sweetness and less acidic. XII Mechanical injury Fruits and vegetables should be in no case injured or damaged other wise injury, such as skin abrasion and tissue bruising will reduce appearance and may be source of infection.
Harvest Factors Maturity at harvest stage is one of the main factors determining compositional quality and storage life of fruit, vegetables and flowers. All fruits, with a few exceptions, reach peak eating quality when fully ripened on the tree. Stage of Harvest: Harvesting can also affect final quality. For instance, when fruits and vegetables are harvested too late or too early in the season, overall taste, texture, and color may be compromised.
Maturity at harvest is therefore an important factor that determines the final quality of the produce. Harvesting of fruits and vegetables at immature stage leads to both qualitative and quantitative losses. Immature fruits fail to ripen normally with low nutritive values and have inferior flavor quality when ripe.