MAJOR-COURSE-9-POST-HARVEST-HANDLING-AND-SEED-TECHNOLOGY-1 (1).pptx
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Post Harvest Handling and Seed Technology (Major Course 9) Prepared By: Junina Lou B. Leodones (LOHB) Table of contents 01 02 Chapter 1: Chapter 2: MATURITY, HARVESTING, BIOLOG...
Post Harvest Handling and Seed Technology (Major Course 9) Prepared By: Junina Lou B. Leodones (LOHB) Table of contents 01 02 Chapter 1: Chapter 2: MATURITY, HARVESTING, BIOLOGICAL ASPECTS OF INTRODUCTORY CONCEPT POST-HARVEST HANDLING 03 04 Chapter 3: Post- Chapter 4: harvest control of Science and technology of senescence, loss seed production, assessment and evaluation processing Definition of Terms ❖ Post harvest- It begins when the process of collecting or separating food of edible quality from its site of immediate production has been completed. ❖ Post-production- is the general term applied to handling of crops from harvest up to the time they reach the consumer ❖ Post harvest handling- a specific term used for the movement of commodities and the operations commodities undergo from harvest to the time immediately prior to meal preparation or food processing. ❖ Harvest- refers to the single deliberate action to separate the foodstuff (with or without associated non edible material) from its growth medium-reaping cereals, picking fruit, lifting fish from water and all succeeding actions are defined as post harvest actions. ❖ Food- is any commodity produced or harvested to be eaten by a particular society. Definition of Terms ❖ Loss- is measured as a reduction in weight in the amount of food available for consumption. ❖ Damage- is physically spoilage, often a partial deterioration of one subjectively judged and very difficult to measure; it is usually reported as a percentage of the food sample. ❖ Assessment- is used to denote the rough quantitative approximation of food loss or to characterize the relative importance of different points of loss in a particular food chain. ❖ Measurement- is as more precise and objective process by which quantitative facts about a loss situation are calculated. ❖ Estimation- is used to describe the process of interpretation of a number of scientific measurements and thus requires the experience and judgment be brought to bear on the factual information under consideration. Definition of Terms ❖ Waste or wastage- are terms included also however, they cannot be precisely defined since they involve subjective and even moral value judgments and depend on the context in which they are used. 01 Chapter 1: Introducti on ➔ There is urgency in increasing food supply to feed the rapidly increasing population in tropical countries. The usual solutions are to increase productivity per unit area. Expand the area of production and control the rate of population growth. Proper postharvest handling is an additional or complementary method of solving food needs. Reducing wastage means increased supply at retail that is available to more people. “The postharvest system consists of a set of operations which cover the period from harvest through to consumption. An efficient postharvest system aims to minimize losses and maintain the quality of the crop until it reaches the final consumer. When food losses are minimized, both food security and income increase and this is of vital importance for small and medium farmers, particularly in developing countries. From a socio-economic point of view, the implementation of an efficient postharvest system in any community must provide equitable benefit to all those involved in the system.” —Grolleaud, 2011 Post- harvest Objectives: ➔ To reduce ➔ To loss in ➔ To maintain increases quantity or the excellent the shelf volume and quality of the life of the the produce crops. product’s (color, taste, qualitative flavor, or aroma). nutritional value. Post- harvest Objectives: ➔ To get ➔ to reduce ➔ To keep the vegetable losses fruits or s and between vegetables fruits harvest and or fresh all consumptio commoditie year n. s free from round. insects and pests Importance of Post Harvest Post-harvest technology is the application of Tech. Post-harvest technology to the post- technology can help to harvest handling and reduce the wastage of storage of agricultural agricultural Post-harvest produce. produce. technology can help Post-harvest to improve the technology can economics of improve the quality agriculture. and shelf life of agricultural products. Post-harvest technology is an important tool in the fight against hunger and malnutrition. Post Harvest Situations ➔ The estimates of postharvest losses of highly perishable produce such as fruits, vegetables and root crops in developing countries can be as high as 50%. The estimated level of postharvest losses in the Asia-Pacific Region is shown below: Country Estimated Level of Losses (%) India 40 Indonesia 20–50 Iran >35 Korea 20–50 Philippines 27–42 Sri Lanka 16–41 Thailand 17–35 Vietnam 20–25 Post-Harvest Losses of Some Crops in The Philippines The province of Pangasinan For mangoes the study revealed registered the highest volume 31,581 fruit produced in the province of Iloilo tonnes and value PhP1.5m and traded in Manila showed the (US$30,000) of post-harvest losses highest post-harvest loss at 33.89 per when mango was traded in Manila cent, the Pangasinan-Manila route because it has higher mango ranked second at 30.85 per cent. production than other provinces. Total post-harvest loss of Estimated volume of post- harvest losses for red onion reached 48,891 freshly harvested onions from the tonnes and a value close to PhP1.96bn. Post- farm in Bongabon, Nueva Ecija to harvest losses for the cold stored onion chain with the same route total to 63.90 per cent, the final market in Divisoria, Manila with estimated volume and value lost at was 45 per cent. 69,333 tonnes and nearly PhP4.01bn Post-Harvest Losses of Some Crops in The Philippines Freshly harvested tomato The total post-harvest produced in Nueva Ecija and loss of freshly harvested traded in Manila incurred tomatoes from the farm in postharvest loss of 10.94 per Bukidnon, Northern Mindanao cent. The volume of post- to the final market in Manila harvest losses reached 1,930 was much higher at 24.14 tonnes with a value of per cent due to longer travel PhP47m. duration. Rice ➔ For rice, losses from harvesting to storage average at 14.85% with a range of 1.13 to 31.94%. The most critical operation was drying with an estimated average loss of 4.50% constituting about 30% of the total losses; this was followed by losses during milling operation at an average of 3.10% or about 21% of the total losses. Corn ➔ For corn, the total losses ranged from 3.7% to 25% with an average of 12.7%. Drying, assessed at 4.6% constituting 37% of the total losses, was the most critical among the various post- production operations. This was followed by storage losses at an average of 3.1% or 24% of the total losses. High-value crops Horticultural crops such as fruits and vegetables are often called high- value crops due to its significant contribution to the agricultural economy. These types of crops that account for 44% of the total volume of food crops, is a very important source of export earnings. The post-harvest losses are: Pineapple 30-40% Banana 25-35% Cabbage 20-30% Garlic 20-42% Potato 12.5% Lettuce 19.6% Tomato 1.6-16% Important Sites of Post-harvest Losses: 15-20% 15-20% Farmer’s Field Packaging 30-40% 30-40% Marketing Transportation Causes of Post-harvest Losses 01 02 03 04 Metaboli Mechanica Development Parasitic c l al diseases All fresh Owing to their tender High post-harvest losses are include sprouting, texture and high caused by the invasion of horticultural crops moisture content, rooting, seed fungi, bacteria, insects and are live organs. germination, which fresh fruits and other organisms. lead to deterioration in The natural vegetables are very Microorganisms attack fresh quality and nutritional susceptible to produce easily and spread process of mechanical injury. value. quickly, because the respiration produce does not have much involves the of a natural defense mechanism and has plenty breakdown of food of nutrients and moisture to reserves and the support microbial growth. aging of these Causes of Post-harvest Losses -Lack of clear concept of 05 06 07 packing house operations. — Lack of awareness among the growers, contractors and even the policy makers. — Lack of infrastructure. — Late realization of its importance, — Inadequate technical support. — Wide gap in technologies available and in vogue. Physiological Lack of market — Inadequate post-harvest deterioration demand Consumption Others; quality control. — Unorganized marketing. 08 — Absence of pre-cooling Fruits and vegetable cells are and cold storage. inaccurate production these losses can be — Inadequate market still alive after harvest and and market information due to inadequate facilities, market continue their physiological may lead to preservation methods intelligence and market activity. Physiological disorders information service (MIS) overproduction of certain at home, methods of may occur due to mineral — Poor storage facilities deficiency, low or high fruits or vegetables which cooking and temperature injury or can’t be sold in time. preparation such as undesirable atmospheric peeling, consumption conditions, such as high styles etc. humidity, physiological deterioration can also occur spontaneously by enzymatic action leading to over-ripeness and senescence, a simple aging phenomenon. Impact of Post-harvest Losses ➔ Post harvest losses of horticultural crops affect both the nutritional status of the population and economy of the country. Nutrition Economy ➔ Fruits and vegetables are rich ➔ Careless harvesting and source of vitamins and rough handling of perishable minerals essential for human bruise and scar the skin, thus nutrition. These are wasted in reducing quality and market transit from harvest to price. Such damaged produce consumer represent a loss in also fails to attract the the quantity of a valuable international buyers, and food. This is important. not bring the exporting country only in quantitative terms, but less profit and bad name. also from the point of view of This ultimately results in quality nutrition huge economic losses to the Technologies for Minimizing the ➔ Losses Fruits and vegetables are perishable in nature. Scientific harvesting and handling are the practical way to reduce the losses due to physical damage, spoilages, due to insect damages and microbial growth. Some technologies for extension of shelf life of fruits and vegetables are: 1. Waxing - It is used as protective coating for fruits and vegetables and help in reduction in loss in moisture and rate of respiration and ultimately results in prolonged storage life. 2. Evaporative cool storage- It is the best short-term storage of fruits and vegetables at farm level. It helps the farmers to get better returns for their produce. In this structure, horticultural crops reduce shriveling and extend their storage life Technologies for Minimizing the 3. Losses Pre-packaging -This technology controls the rate of transpiration and respiration and hence keeps the commodity in fresh condition both at ambient and low temperature. It can able to bring revolutionary progress in our trade practice and also benefit the consumer and the producer because of its low cost and ready availability. 4. Cold storage-These structures are extensively used to store fruits and vegetables for a long period and employ the principle of maintaining a low temperature, which reduces the rate of respiration and thus delays ripening. 5. Controlled Atmosphere (CA) storage- It is based, on the principle of maintaining an artificial atmosphere in storage room, which has higher concentration of CO2 and lower concentration of 02 than normal atmosphere. This reduces the rate of respiration and thus delays aging. This method of storage is very effective when combined with low temperature storage. Technologies for Minimizing the 6. Modified atmosphere Losses packaging (MAP)- These packaging modify the atmosphere composition inside the package by respiration. This technology is successful to extend the shelf life of (Cavendish banana, carrots capsicum, green chili and tomatoes by 15, 14, 13, 8 and 15 clays as against 5, 7, 8, 4 and 7 days in control respectively, under ambient conditions. Storage of Papaya can be extended 4 weeks when stored at 10 -12 °C under modified atmosphere (MA) conditions by wrapping them in low density polyethylene (LDPE) bag. Using this technique, the fruit can be transported to different markets in refrigerated sea containers with Temperature Sea at 10-12 °C. Fruits ripen within 3-4 days after arrival when placed at ambient temperature. While using optimum low temperature, storage life of Cavendish banana, capsicum, green chili and tomato can be extended to 42,21,28 and 30 days in comparison to 21, 10,21 and 15 days respectively. 7. Cold chain- Logistics management process for perishable products that need refrigerated temperatures to maintain quality and safety from end to end. Technologies for Minimizing the 8. Losses Irradiation-It is the newer technologies that can be gainfully employed during storage to reduce post-harvest losses and extend storage life of fruits and vegetable. When fruits and vegetables exposed to ionizing radiation (such as gamma- rays) at optimum dosage delays ripening minimizes insect infestation, retards microbial spoilages, control sprouting, and rotting of onion, garlic and potato during storage. It is also used as a disinfection treatment and controls fruit fly on citrus, mango seed weevil and papaya fruit fly. 9. Edible coatings -These are continuous matrices prepared from edible materials such as proteins, polysaccharides and lipids. They can be used as film wraps and when consumed with the food, become an ingredient of the food. They not only minimize the post harvest losses but also need for energy intensive operations and controlled atmosphere storage. They can control migration of gases, moisture, oil, fat, and solutes, as well as retain volatile flavouring compounds. An edible coating improves structural integrity and mechanical handling and carry product so that they help to maintain quality and inhibit microbial growth causing deterioration of the product. Technologies for Minimizing the 10. Others; Losses — Facilities/ services like grading, washing, cleaning, scientific harvesting and the like, in respect of perishables at the farm level. — Cold storage facilities should be extended to tropical fruits and vegetables. Handling protocols should be established for crops other than mango, citrus, grapes and capsicum to improve the shelf life and export. — The issue relating to increasing the shelf life of horticultural products needs to he addressed. — Appropriate packaging material for export of fresh fruits, vegetables and for modified atmosphere packaging should be developed. — Value addition needs to be viewed in a wider perspective than mere processing to ensure better return to the producer/ farmer, besides providing better quality product to the consumer. — Development of natural food columns, fiber, single cell protein and food grade enzymes from processing wastes will be useful. Characteristics of Perishable Crops that Determine Postharvest Life 1. Energy requiring – even after harvest, a fruit, vegetable or florist crop is alive so metabolism continues until the crop deteriorates. In order to maintain the high degree of organization needed to enable it to carry on its metabolic processes, energy in the form of adenosine triphosphate (ATP) generated from transpiration is necessary. 2. Constant state of change- deterioration process cannot be stopped but can be slowed down within certain limits Characteristics of Perishable Crops that Determine Postharvest Life ➔ Senescence – the final stage in the life of a plant or its part in which a series of normally irreversible events are started leading to breakdown of structure and loss of function of certain tissues. Changes that determine the acceptability of a produce; 1. Appearance 2. Flavor 3. Texture 4. Nutritive Value Characteristics of Perishable Crops that Determine Postharvest Life Factors that influence these changes; 1. Temperature 2. Relative humidity 3. Light 4. Gases 5. Gravity ➔ High temperature and low relative humidity hasten undesirable changes in all commodities. The slower the undesirable changes, the longer postharvest life. The solution may be slowdown undesirable changes by putting commodities in an environment that would reduce such changes to a minimum Characteristics of Perishable Crops that Determine Postharvest Life 3. High in water content- fresh fruits, vegetables, florist crops consist mainly of water, it could be as high as 98% by weight in fully turgid leaves.When a commodity is harvested, it can no longer replace the water that is lost through transpiration. The high the amount of moisture in the commodities has to be maintained to retain their quality. The faster the commodity losses water, the faster it deteriorates and loses its freshness. Transpiration should be slowed down through application of postharvest technologies Characteristics of Perishable Crops that Determine Postharvest Life 4.React to adverse environmental conditions-While many fresh produce have fundamentally short shelf-life due to their nature, their postharvest life is further shortened by unfavorable factors of the environment. 5. Subject to attack by pathogens and insects-A fresh fruit or vegetables are not only bagful of food for human beings but also for microorganisms and insects as well. The faster the spread and growth of microorganisms, the faster the deterioration of the commodity. Overview of Postharvest Post-production Handling ➔ handling crop from harvest up to the time they reach the consumer. Postharvest handling ➔ movement of commodities and the operations commodities undergo from harvest to the time immediately prior to meal preparation or food processing. Main Division of Post Production 1. Primary processing – handling of produce to make them suitable for manufacturers or consumers. Field of study: seed technology, postharvest handling of fruits and vegetables and primary processing of plantation crop such as coffee and cacao. 2. Secondary processing – transforms a produce intro another form that can no longer be subjected to another change. It includes food and industrial processing. Postharvest Handling Technology ➔ the main objective is to keep the harvested commodity in an acceptable state and for food crops always palatable 1. Handling of perishable crops: fruits, vegetables, cut flowers and florist greens, young coconut, perishable root crops and nursery stocks. 2. Handling of durable crops: cereal grains (rice and corn), grain legumes (peanut) Importance of Proper Post Harvest Handling 1. Increases the amount food available with no or little production inputs, area of production and population control measures. 2. It improves nutrition – minimizes loss of nutrients 3. Reduces garbage disposal and pollution problems especially in big cities.) Type of Post Harvest Losses A. Quantitative B. Qualitative loss loss ➔ actual physical loss, ➔ impairment of quality, loss in terms of loss in terms of number, weight or wholesomeness value, volume. In the appearance, taste or Philippines, an texture making the estimated 28-42 food less desirable and percent of the fruits leading to lower price. and vegetables are loss (NAS, 19878). ➔ In the Philippines, the amount of fruit and vegetables lost each year has been estimated 29 metric tons of protein, which could supply the protein requirements of 1.3 million Filipinos. ➔ In pechay, 1.04 percent of the protein and 8 percent of the Vitamin C are lost after one hour at a room temperature of 28°C and a relative humidity of 60%. If it is exposed to sunlight, as is experienced during retail, the losses are even much higher. Components of Quality Appearanc e Texture Flavor Size Firmness taste and smell Shape Softness Sweetness Color Sourness Crispness Bitterness Gloss Mealiness Aroma Defects Off-flavors ➔ A combination of characteristics, attributes, or properties that gives the commodity value as a human food. Components of Quality Nutritive Value Safety Carbohydrate Toxicant s Contaminants Proteins Residues Vitamins Microbes Minerals ➔ A combination of characteristics, attributes, or properties that gives the commodity value as a human food. Factors Affecting Quality and Storage Life 1. Maturity 2. Storage temperature and time taken to arrive at the optimal temperature 3. Prevention of water loss. 4. Freedom from mechanical damage. 02 Chapter 2: Maturity, Harvesting,Biological Aspect of Post Harvest Handling I. MATURITY ➔ It is the stage of fully development of tissue of fruit and vegetables only after which it will ripen normally. During the process of maturation the fruit receives a regular supply of food material from the plant. When mature, the abscission or corky layer which forms at the stern end stops this inflow. Afterwards, the fruit depend on its own reserves, carbohydrates are dehydrated and sugars accumulate until the sugar acid ratio form. In addition to this, typical flavor and characteristic color also develop. It has been determined that the stage of maturity at the time of picking influence the storage life and quality of fruit. A. Types of Maturity 2. Physiological 1. Horticultural Maturity Maturity ➔ It is a developmental ➔ It refers to the stage in the development of the fruits and stage of the fruit on the vegetables when maximum growth tree, which will result in and maturation has occurred. It is a satisfactory product usually associated with full ripening in after harvest. the fruits. The Physiological mature 3. Commercial stage is followed by senescence. Maturity 4. Harvest Maturity ➔ It is the state of plant organ ➔ It may be defined in terms of required by a market. It Physiological maturity and commonly bears little horticultural maturity, it is a stage, relation to Physiological which will allow fruits / vegetables at maturity and may occur at its peak condition when it reaches to the consumers and develop any stage during acceptable flavor or appearance and development stage. having adequate shelf life. B. Criteria of Maturity for Harvesting Fruits & Vegetables 1. Skin color Loss of green color in citrus and red color in tomato. 2. Shape, size and flavor Sweet corn is harvested at immature stage, smaller cobs marketed as baby corn. Okra and cowpea are harvested at mature stage (pre fiber stage). In chili, bottle gourd, bitter gourd, cluster beans maturity is related to their size. Cabbage head and cauliflower curd are harvested before unpleasant flavor. 3. Abscission and firmness Musk melon should be harvested at the formation of abscission layer. In cabbage and lettuce should be harvested at firmness stage B. Criteria of Maturity for Harvesting Fruits & Vegetables Fruits Physical Chemical 1. Mango Olive green color with clear lenticels, shoulder Starch content, flesh colour development size sp. gravity, days from fruit set 2. Banana Skin color, drying of leaves of the plant, Pulp/peel ratio, starch content brittleness of floral ends, angularity of the fruit, and days from emergence of inflorescence. 3. Citrus Color break of the skin from green to orange, Sugar/acid ratio, TSS size 4. Grapes Peel color, easy separation of berries, TSS 18-12 Thompson seedless, characteristic aroma 12-14 for Bangalore Blue, 14-16 for Anab-e-shahi 5. Apple Color size Firmness as measured by pressure tester 6. Papaya Yellow patch or streaks. Jelliness of the seed, seed colour C. Time Taken from Pollination to Horticultural Maturity Vegetables Time to harvest Maturity (days) 1. Ridge gourd 5-6 2. Squash 7-8 3. Eggplant 25 - 40 4. Okra 4-6 5. Pepper (green stage) 45 - 55 6. Pepper (red stage) 60 -70 7. Pumpkin (mature) 65 - 70 8. Tomato (mature green) 35 - 45 9. Tomato (red ripe stage) 45 - 60 10. Peas 30 - 35 D. Factors Affecting Maturity 3. Size of Planting 1. Temperature 2. Soil Material Higher temperature gives early Soil on which the This factor in maturity. Sun-scorched portions fruit tree is grown propagated fruits affects of fruits are characterized by fruit maturity. e.g. In chlorophyll loss, yellowing, affects the time of pineapple, the number disappearance of starch and maturity. e.g. of days taken from other alcohol insoluble Grapes are flowering to fruit material, increase in TSS harvested earlier on maturity was more by content, decrease in acidity and light sandy soils planting large suckers 4. Closer softening. than5.onPruning heavy clays. and slips than by smaller ones. Spacing Intensity 6. Girdling Process of constricting the periphery of Close spacing of hill It enhanced the a stem which blocks the downward translocation of CHO, hormones, etc. bananas hastened maturity of Beyond the constriction which rather maturity Flordasun and accumulates above it. In Grapevines it sharbati Peaches. hastens maturity, reduces the green berries in unevenly maturity cultivar and lowers the number of short berries. It is ineffective when done close to harvest. CPA has an additive effect with girdling E. Maturity Index ➔ The factors for determining the harvesting of fruits, vegetables and plantation crops according to consumer’s purpose, type of commodity, etc and can be judged by visual means (color, size, shape), physical means (firmness, softness), chemical analysis (sugar content, acid content), computation (heat unit and bloom to harvest period), physiological method(respiration). These are indications by which the maturity is judged. Various index are; 1. Visual Indices- It is most convenient index. Certain signals on the plant or on the fruit can be used as pointers. E.g. drying of top leaves in banana, yellowing of last leaf of peduncle in jackfruit. 2. Seed Development- it can also be used as an index of fruit maturity e.g endocarp hardening for stone and fiber development for mango. 3. Start of Bud Damage- occasionally it can be used as an index of maturity in mango. E. Maturity Index 4. Calendar Date- For perennial fruit crops grown in seasonal climate which are more or less uniform from year to year, calendar date for harvest is a reliable guide to commercial maturity. This approach relies on a reproducible date for the time of the flowering and a relative constant growth period from flowering through to maturity 5. Heat Units- Harvest date of newly introduced fruits in a widely varying climate can be predicted with the help of heat unit. For each cultivar the heat requirement for fruit growth and development can be calculated in terms of degree days: Maturity at higher temperature is faster as the heat requirement is met earlier E. Maturity Indices of Fruits Fruits Maturity Indices 1. Banana when the ridges on the surface of skin change from angularity to round 2. Guava TSS acid ratio, specific gravity and color determined the maturity in guava 3. Pomegranate Sugar percentage should be 12-16% and acid percentage 1.5—2.5% 4. Mango This can be judged when one or two mangoes ripen on the tree are fall on the ground of their own accord 5. Muskmelon Easily separated from vine with a slight twist leaving clean cavity (full slip stage). 6. Watermelon Dull hollow sound when thumped E. Maturity Indices of Vegetables Root, bulb and tuber crops Maturity Indices 1. Radish and carrot Large enough and crispy 2. Potato, onion and garlic Tops beginning to dry and topple clown 3. Yams, bean and ginger Large enough E. Maturity Indices of Vegetables Fruit Vegetables Maturity Indices 1. Cowpea, snap bean, sweet pea, winged bean Well filled pods that snap readily 2. Lima bean and pigeon pea Well filled pods that are beginning to lose their greenness 3. Okra Desirable size reached and the tips of which can be snapped readily 4. Snake gourd Desirable size reached and thumbnail can still penetrate flesh readily 5. Egg plant, bitter gourd, slicing cucumber Desirable size reached but still tender 6. Tomato Seeds slipping when fruit is cut, or green color turning pink II. HARVESTING ➔ The goals of harvesting are to gather a commodity from the field at the proper level of maturity with a minimum of damage and loss, as rapidly as possible and at a minimum cost. This is achieved through hand- harvesting in most fruit, vegetable and flower crops. A. Types of Harvesting 1. Hand Harvesting Hand harvesting has a number of advantages over machine harvest. People can accurately determine product quality, allowing accurate selection of mature product. This is particularly important for crops that have a wide range of maturity and need to be harvested several times during the season. Properly trained workers can pick and handle the product with a minimum of damage. Many fresh- market products have a short shelf life if they are bruised or damaged during harvest and handling. A. Types of Harvesting 2. Mechanical Harvesting Mechanical harvest is currently used for fresh-market crops that are roots, tubers, or rhizomes and for nut crops. The main advantage of mechanical harvest equipment is that machines can often harvest at high rates. Tree nut harvesters, for eg. attaching a shaking mechanism to the tree and remove most of the nuts in few seconds B. Demerits of Mechanical Harvesting Machines are rarely capable of selective harvest. Mechanical harvesting will not be feasible until the crop or production techniques can be modified to allow one time harvest. Harvesting machines often causes excessive product perennial crops eg. Bark damage from a tree shaker. The harvesting machines are quite expensive. III. Biological Aspects of Post-Harvest ➔ Effective management duringHandling the postharvest period, rather than the level of sophistication of any given technology, is the key in reaching the desired objectives. While large scale operations may benefit from investing in costly handling machinery and high tech postharvest treatments, often these options are not practical for small-scale handlers. Instead, simple, low cost technologies often can be more appropriate for small volume, limited resource commercial operations, farmers involved in direct marketing, as well as for suppliers to exporters in developing countries. A. Nutrition of Fresh Produce Crops 1. The contribution of fresh produce to human nutrition Most people eat a mixed diet of foods from plants and animals. In most societies, starchy staple foods, particularly cereal grains, are the main source of energy in the human diet. In certain areas, especially in the humid tropics, root and tuber crops, together with plantains and similar plants, are either the staple food or a supplement to cereal staples. Fruit and vegetables are important sources of essential minerals and vitamins in the human diet. When eaten together with some root (potato, sweet potato) and leguminous (pigeon peas, beans, lentils) crops, they provide a proportion of protein requirements as well as variety in flavor and color. 2. Energy requirements Starches and sugars, formed within the plant for its own use, are used as energy foods. Starch is the main component of root and tuber crops and also of plantains and green bananas. Oils and fats are also energy foods. Fresh produce contains only small amounts except for avocados, which contain 15-25 percent oil 3. Food for body growth and repairProteins are essential to the building and repair of muscles and organs. They are needed in large amounts by growing children. Fresh produce is low in protein content, although on a dry-weight basis some root crops such as sweet potato and potato as well as leaves of several crops have protein contents approaching that of animal products. Cassava has very low protein content. Minerals are required for health but only in small amounts as compared with energy foods and proteins. Sodium, potassium, iron, calcium, phosphorus and many trace elements are essential. Vegetables contain significant amounts of calcium, iron and some other minerals. 3. Food for body growth and repair Vitamins are essential for the control of chemical reactions in the body. Fruit and vegetables, and to a lesser extent root crops, are important sources of vitamin C and other essentials. Fiber or "roughage" is found in large amounts in fresh produce. Though indigestible, it plays an important part in the function of digestion, and a diet containing high fiber content is shown by medical studies to reduce Table 1. Vitamins supplied by fruit, vegetables and root crops Vitamin Name Source A Retinol From carotene in dark green leaves, tomatoes, carrots, papayas B1 Thiamine Pulses, green vegetables, fruit (cereal grains have B. in germ and outer-seed coat) B2 Riboflavin Green leafy vegetables and pulses B3 Niacin (nicotinic acid) Pulses, peanuts B6 Pyridoxin Bananas, peanuts C Ascorbic acid Dark green leaves, spinach, cauliflower, sweet pepper, citrus, guava, mango, papaya ------- Folic acid Dark green leaves, broccoli, spinach, beets, cabbage, lettuce, avocados 4. Loss of food value in fresh produce The keeping and the preparation of fresh produce after harvest affects its nutritional value in several ways: The keeping and the preparation a. Dry-matter content (the energy supply) is reduced with time as the continuation of living processes within the produce uses up stored food reserves. of fresh produce after harvest b. Vitamin C content decreases with time after harvest, and little may remain after two or three days. affects its nutritional value in c. Cooking partially destroys vitamins C and B1. Raw fruit and vegetables are several ways: particularly valuable provided they are grown and handled hygienically. d. Peeling may cause significant loss of food value, especially in potatoes, where the protein content is just beneath the skin. e. Water used in cooking vegetables or fruit contains the dissolved minerals and trace elements of the food and should not be thrown out but used in soups or in preparing other foods. B. Morpho-anatomical basis of postharvest handling technologies 1. Plant part or organ utilized -The response of a commodity to its environment and method of handling depends on what organ it is, e.g. pechay leaves and sunflowers wilt easily, cut flower buds open, mango fruits ripen, onion bulbs sprout and asparagus shoot tip elongate. 2. Nature of fruit wall ○ Fruits and fruit vegetables vary in nature of their fruit walls ○ The fruit wall consists of both the peel and the edible portion excluding the seed ○ Rind: tough and leathery peel of fruits (citrus and watermelon) ○ Aril: edible portion of rambutan, mangosteen, durian and lanzones ○ The nature of the fruit wall influences the effect on environment on the organ, and its susceptibility to mechanical damage, insects and B. Morpho-anatomical basis of postharvest handling technologies Examples: ⮚ Citrus have thick peel thus less susceptible to bruises but pressure or impact results in a brown discoloration (olleocellosis) due to release of oil from oil cells. ⮚ Tomatoes have thin outer part of the fruit wall and succulent pulp that make them susceptible to damage. ⮚ Starfruit and apples have thin but leathery peel so they are less susceptible to bruises – Watermelon and squash are more resistant to damage than tomatoes and banana because of their thick and hard fruit walls. B. Morpho-anatomical basis of postharvest handling technologies 3. Nature of cuticle Cuticle non-cellular layer above the epidermal cells.Thicker and complex cuticle protects the commodity from ○ Excessive moisture loss ○ Pathogen attacks ○ Harmful chemical penetration ○ Mechanical injuries ○ Abrupt temperature changes and ○ Loss of flavor components B. Morpho-anatomical basis of postharvest handling o technologies Mature fruits have thick, complex and waxy cuticles ○ Immature one have thin, irregular and less waxy cuticles ○ Immature fruits deteriorate at a faster rate than mature ones ○ Some parts of a commodity may have thinner cuticle e.g. in winged bean, the wings have thinner cuticle hence wilts faster than the other part of the pod ○ Some fruit have thick wax while some have none e.g. lanzones has no waxy layer in epidermis thus loses water fast, while banana fruits are very waxy thus deteriorates at slower B. Morpho-anatomical basis of postharvest handling technologies 4. Number of Stomates - Stomates are the main passageways for the loss of water and entry of air for respiration. ○ More stomates, faster deterioration ○ Cuticles covers some of the stomates during maturation ○ A banana fruit has only 500 stomates per square centimeter, while a pechay leaf has 13,000 per square centimeter in the lower surface. B. Morpho-anatomical basis of postharvest handling technologies 5. Amount of hairs/ Spinterns Hairs or spines are elongations of the epidermal cells ○ Emergence refers to visible hairs or spines ○ Trichomes refers to tiny hairs that are not visible ○ Spintern is the special name for the hair of rambutan The more trichomes and emergences, the faster the deterioration since they increase the surface are to volume ratio, respiration rate and transpiration rate of the commodity. Example: rambutan is very B. Morpho-anatomical basis of postharvest handling technologies 6. Amount of Lenticels Lenticels are circular groups of protruding air-filled cells with a central opening which often takes the place of stomates in fruits, stems and roots. ○ The dots that can be seen in a potato when wet are swollen lenticels. ○ The corky cells of the lenticels provide some resistance mechanical injury but also allow water to escape and gases to diffuse in or out B. Morpho-anatomical basis of postharvest handling technologies 7. Presence of Laticifiers Laticifiers – sap or latex producing ducts surrounding the vascular bundles ○ Latex when allowed to drip on the peel of mango and banana results in a decline in quality ○ Latex corrodes and discolors the peel of the fruit and also serves as food for microorganisms ○ Avoid latex flow on the skin or wash off latex before it hardens B. Morpho-anatomical basis of postharvest handling technologies 8. Compactness of cells Arrangement of cells in some fruit pulp are very compact Fruits with compact cells like mango and potato are very susceptible to physiological disorders since gases such as oxygen cannot readily enter into while carbon dioxide cannot quickly exit from the cells. Lack of oxygen in mango would result to internal breakdown (white starchy areas) In potato, suffocation due to depletion of oxygen would result to death of internal tissues called blackheart. B. Morpho-anatomical basis of postharvest handling technologies 9. Changes in Organelles Respiration takes place at the mitochondria in cells. Destruction of these are reflected as changes in the cell and eventually in the commodity. Examples: ○ chilling injury – associated with mitochondrial changes. ○ Changes in color of the commodity – destruction or formation of pigment bearing organelles (plastids). C. Chemical basis of Postharvest Handling Technologies 1.) Changes in color- this is due to changes in pigments. Carotenoids have similar structure i.e. lycopene (red), carotene (orange). Yellow green citrus turns into orange because of the formation of orange. Tomato in the Philippines have very little lycopene especially when grown during hot months because high temperature slows down the formation of enzyme necessary to form lycopene. C. Chemical basis of Postharvest Handling Technologies 2.) Changes in taste and flavor- ripe fruits are sweeter because they contain more soluble sugars as the complex starch is converted to sweet monosaccharides C. Chemical basis of Postharvest Handling Technologies 3.) Changes in texture- softening of fruits is caused by a conversion of starch to simpler carbohydrates or of protopectins into soluble pectins. Protopectin is a cementing substance D. Physiological Basis of Postharvest Handling Technologies Respiration is a biological process by which organic material like starch, proteins or fats are broken down to simpler forms accompanied by a release of heat and energy. It is a very good indicator of potential postharvest life. The faster the respiration means faster release of heat which increases the temperature of the surroundings of the commodity especially in package. This results in further increase in respiration. Commodities with high Classification of Commodities According to Rates of Respiration 1. Commodities with high respiration rates: organs at immature stage Examples: Asparagus shoot tip, cauliflower, young corn cob (570.6 grams CO2/kg/hr), bean sprouts, and bamboo shoot Classification of Commodities According to Rates of Respiration 2. Commodities with low respiration rates: storage organs Examples: Onions, potato, gabi, sweet potato, yam (1.52 mg CO2/kg/hr). 3. Commodities with intermediate rates: fruits harvested physiological maturity Examples: Lanzones (70 mg CO2/kg/hr) at ambient temperature. Methods to Slow Down Respiration Cold storage Low Oxygen CO2 storage The low Nitrogen Keeping a temperature inside gas is introduced high Carbon Dioxide cold storage unit into the storage by level (up to 14%) can halt the growth of cylinder to reduce stop the ethylene these pathogenic the oxygen level production and fungi, ensuring that after room is filled therefore, slow down spoilage of fruits and sealed. the ripening process and vegetables is and prolong shelf kept to a minimum. life. IV. POST HARVEST HANDLING Being living organs, fruits and vegetables continue to respire even after harvesting when they have a limited source of food reserves. In addition to degradation of respiratory substrates, a number of changes in taste, color, flavor, texture and appearance take place in the harvested commodities which make them unacceptable for consumption by the consumers if these are not handled properly. Post harvest technology starts immediately after the harvest of fruits and vegetables. The whole process of processing the commodities is categorized as handling of fresh produce. Post harvest Technology of fresh fruits and vegetables combines the biological and environmental factors in the process of value A. Post-harvest handling processes 1. PRECOOLING Precooling (prompt cooling after harvest) is important for most of the fruits and vegetables because they may deteriorate as much in 1 hour at 32°C. In addition to removal of field heat from commodities, precooling also reduces bruise damage from vibration during transit. Cooling requirement for a crop vary with the air temperature during harvesting, stage of maturity and nature of crop. Methods a.ofCOLD Precooling AIR (ROOM COOLING) - Cool air is circulated by convection Suitable Vegetables All fruited vegetables and fruits Advantages Clean and simple Low installation & maintenance cost Provides temporary storage after pre- cooling Disadvantages Slow and uneven cooling at the beginning Not suitable to leafy vegetables due to Methods of Precooling b. VACUUM COOLING - At reduced atmospheric pressure within the vacuum chamber, water rapidly evaporates from the produces’ surface, removing heat in the process. Suitable Vegetables Leafy vegetables and mushrooms Advantages Rapid and uniform cooling for all vegetables High energy efficiency Disadvantages Risk of wilting due to moisture loss High cost Requires packaging with holes for water evaporation. Methods of Precooling c. FORCED AIR COOLING - Cold air is drawn and forced through crates of vegetables covered by a canvass sheet. Suitable Vegetables All leafy, fruited and rooted vegetables Advantages Clean,simple and rapid High heat transfer performance Low installation and maintenance cost Disadvantages Slower as compared to vacuum cooling Methods of Precooling d. HYDRO COOLING Vegetables are showered with or submerged in cold water that is circulated through the heat exchanger Suitable Vegetables Fruited vegetables and fresh fruits tolerant of prolonged exposure to wet conditions Advantages Rapid and high energy efficiency Provides means to clean vegetables (e.g. with chlorinated water) to prevent spoilage Disadvantages Another step of drying required Additional effort required to monitor water quality and cleanliness of cooler daily Methods of Precooling e. ICE COOLING Layers of crushed ice are added on top of the vegetables Suitable Vegetables Broccoli, carrots, Chinese cabbage, green onions, and commodities that have a high respiration rate Advantages Rapid and high energy efficiency Prevents any moisture loss from vegetables Disadvantages Additional weight (from crushed ice and high water content from melting ice) could increase the risk of physical injury and rotting of vegetables Risk of chilling injury to vegetables if period of A. Post-harvest handling processes 2. WASHING, CLEANING, TRIMMING Before fresh fruits and vegetables are marketed various amounts of cleaning are necessary which typically involves the removal of soil dust, adhering debris, insects and spray residues. Chlorine in fresh water is often used as disinfectant to wash the commodity. Some fungicides like Diphenylamine (0.1 - 0.25%) or ethoxyquin (0.2 - 0.5%) may be used as post harvest dip to control the disorders. Eg. Apple superficial scald. For cleaning of some fruit type vegetables (melons, eggplants, tomatoes, cucumber) they should be wiped with damp cloth. Many vegetable need trimming, cutting and removal of unsightly leaves or other vegetative parts A. Post-harvest handling 3. SORTING, GRADING AND SIZING processes Sorting is done by hand to remove the fruits which are unsuitable to market or storage due to damage by insects, diseases or mechanical injuries. The remainder crop product is separated into two or more grades on the basis of the surface color, shape or visible defects. After sorting and grading, sizing is done either by hand or machine. Machine sizers work on two basic principles: weight and diameter. Sizing on the basis of fruit shape and size are most effective for spherical (Oranges, tomato, certain apple cultivars) and elongated (Delicious apples and European pears or of non-uniform A. Post-harvest handling processes 4. CURING Curing is an effective operation to reduce the water loss during storage from hardy vegetables viz, onion, garlic, sweet potato and other tropical root vegetables. The curing methods employed for root crops are entirely different than that from the bulbous crops (onions and garlic). The curing of root and tuber crops develops periderms over cut, broken or skinned surfaces wound restoration. It helps in the healing of harvest injuries, reduces loss of water and prevents the infection by decay pathogens. Onions and garlic are cured to dry the necks and outer scales. For the curing of onion and garlic, the bulbs are left in the field after harvesting under shade for a few days until A. Post-harvest handling processes 5. WAXING - Waxing generally reduces the respiration and transpiration rates, but other chemicals such as fungicides, growth regulators, preservative can also be incorporated specially for reducing microbial spoilage, sprout inhibition etc. The advantages of wax application are: Improved appearances of fruit. Reduced moisture losses and retards wilting and shrivelling during storage of fruits. Less spoilage specially due to chilling injury and browning. Creates diffusion barrier as a result of which it reduces the availability of 02 to the tissues thereby reducing respiration rate A. Post-harvest handling processes 5. WAXING Protects fruits from micro-biological infection. Considered a cost effective substitute in the reduction of spoilage when refrigerated storage is unaffordable. Wax coating are used as carriers for sprout inhibitors, growth regulators and preservatives. The principal disadvantage of wax coating; development of off- flavor if not applied properly. Adverse flavor changes have been attributed to inhibition of O2 and CO2 exchange thus, resulting in anaerobic respiration A. Post-harvest handling processes 6. PACKAGING Proper or scientific packaging of fresh fruits and vegetables reduces the wastage of commodities by protecting them from mechanical damage, pilferage, dirt, moisture loss and other undesirable physiological changes and pathological deterioration during the course of storage, transportation and subsequent marketing. Packaging cannot improve the quality but it certainly helps in maintaining it as it protects produce against the hazards of journey. Striking developments have been in the field of packaging of horticultural produce and the gunny bags, grasses and stem leaves used so far for packaging are now being replaced by a variety of containers such as wooden boxes, baskets woven from A. Post-harvest handling processes 7. STORAGE A number of storage techniques (ground storage, ambient storage, refrigerated storage, air cooled storage, zero energy storage, modified atmospheric storage, hypobaric storage and controlled atmosphere storage) are being used for fruits and vegetables depending upon the nature of the commodity and the Thank You for Listening! CREDITS: This presentation template was created by Slidesgo, and includes icons by Flaticon, and infographics & images by Freepik
