http://www.aaa3.net/connors-rating-scale-purchase/
Post Harvest Management
Healing
The only post-harvest treatment required for long-term storage of the onion bulb is a cure full of light bulbs. Curing is a drying process for drying the necks and outer scale leaves of the bulbs to prevent moisture loss and damage attack during storage. What is essential for cure are heat and good ventilation, preferably with low humidity. This dries the neck and two or three outer layers of the bulb. The outermost layer, which may be contaminated with soil, usually falls out easily when the bulbs are cured, exposing the dry layer beneath, which should have an attractive appearance. Onions are considered cured when the neck is tight and the outerscales until touch dry. This condition is reached when onions have lost 3-5% of weight.
If the onions not be dried in the field, can be collected in trays which are stacked in a warm, well ventilated area covered.
In cool, damp climates, onions in bulk stores ventilated drying with artificial heat blown through the bulk of the conduit to a temperature of 30 degrees Celsius.
Onions also can be cured by tying the tops of the bulbs in bunches and hang them on a horizontal pole in a shaded and well ventilated. Curing improves the color shade and the bulb reduces losses significantly during storage
Classification
After curing onions are sorted manually before they go into storage or marketing. The thick neck, with screws, double, injured and decayed bulbs are well chosen deformed small bulbs. Selection and classification is performed after storage also seeking a better price. The exterior dry scales usually rub during the classification process, giving the Onion a better look for the market. It has been shown that if storage is available after the correct classification classification and storage losses are reduced.
For local market onions are ranked according to their size.
Extra large onion (> 6 cm in diameter.)
Middle (4-6 cm in diameter.)
Small (2-4 cm in diameter.)
The extra large onions in great demand and sold very cheaply.
General features
The bulbs must:
• be reasonably uniform in shape, size and color of pungency of the variety and type of
• be mature, solid feel, sufficiently firm hold on hard leather.
• be over cured and dried.
• be free of dust and other foreign material.
• be free from defects, sick, broken and damaged caused by the seeds bulbs stems, caps
• OOTS, humidity, dry sun scald, sprouting, mechanical or other injuries and stains.
• be free of mold, soft rot and attacks insects.
•% of the stem of seeds or bulbs screwed, will not exceed 20% in kharif onion Nasik.
Bangalore and Krishnapuram onion is free of bottlenecks or doubles.
Grade designations and definitions of quality for the export of onions:
different size, but not below 15
1. Tolerance to the size of large onions: the case of accidental errors in the size, no more than 5% by weight of the bulbs in any lot may next lower grade being the minimum diameter prescribed in Nasik, Saurashtra, Bellary and onions Poona. Podisu If this error not larger than 10% weight. In this case, the smallest handful of onion to be taken to measure the diameter.
2. Defective, diseased or damaged, it is understood malformed lamps and bulbs internally or externally damaged, diseased or discolored material affecting quality. The onion may not exceed 2% in any lot.
General: The grade will be allowed to be packed only against irrevocable letter of credit.
# NS grade: This is not a degree in the strict sense but it is anticipated that the onions not included in the standard rate. Onions in this category are exported only against specific order from foreign buyer induction quality.
Packaging
Packaging should be small to facilitate handling during transport and may vary depending on market demand. Onions are packed in jute (burlap) bags to transport yard, or is loose. For safe handling, 40 kg open mesh jute bags weighing 200-300 g should be used in the domestic market. For export, large common onions are packed in 5 to 25 kg size open mesh jute bags. Bangalore Rose and multiplier onions are packed for export in 14 to 15 kg wooden baskets. nylon net bags, when used for packaging have resulted in less storage loss due to ventilation.
Manipulation
Bulbs used for storage should be free of cuts and handled with extreme care. Onions should not be dropped on the surface Elastic no more than 6 feet tall. If the onions are stacked in the warehouse after packing or trucks, the best height is 2-2.5 meters. Losses due to rot is reported to be longer if the onions are stored in jute bags or loose in wooden boxes.
Storage
Proper storage of bulbs needed both for consumption and for seed production. Onions should not be stored dry properly unless either the field or by artificial means. It is necessary to dry the tissues of the neck and outer scales up creaking when driving otherwise the bulbs will rot in storage. Outbreak of onion is controlled by temperature. The temperature between 10-25 ° C increased germination. Rooting is influenced by relative humidity (RH). More than relative humidity, the more the roots. Loss more weight when the temperature is above 35 ° C. Under environmental conditions that onions are stored at a temperature of 30-35 ° C with relative humidity of 65-70%. In cold storage, the temperature is kept at 0-2 ° C, while relative humidity is maintained at 60-75%. Outbreak effectively if it is found at 2500 Maleic hydrazide ppm is sprayed at 75-90 days after transplantation.
The effect is, however, more pronounced in the kharif season in the rabi season. Rot storage can be controlled if the cleanup is well maintained in the store and crops were sprayed with 0.1% Carbendazim 90 days after transplantation and just before harvest. In India, the practice of farmers storage methods. Onions are stored in bulk in special houses with thatched roof and side walls are made with bamboo sticks or wire mesh for good air circulation. In northern India, the parties also are covered with burlap. Onions are stored in these sheds by spreading the wet and dry test soil or racks. Periodic rotation of the bulbs or the elimination of rotten, damaged and sprouted bulbs be done. Very well ventilated and improved storage structures with racks or levels two or three layers of bulbs would be desirable for proper storage.
The main features of improved storage structures are as follows
• Construction of storage godown raised platform helps in reducing from moisture and humidity
• The use of Mangalore tiles or other suitable material prevents high temperature accumulated inside.
• Height Increase cost center and more is better for air circulation and prevent moist microclimate inside godown.
• Down provides ventilation free and rapid flow of air to prevent formation of pockets of heat and moisture between the layers of onion.
• Avoid direct sunlight onion bulbs sunscald reduce discoloration and deterioration of quality.
• Restricting the width of each stack of 60-70 cm for the wet cold weather, 75-90 cm for warm and humid climate and 90-120 cm for the conditions of mild and dry weather
• Restriction of the stacking height of 100 cm of small onion and the multiplier and warm climate and 120 cm for the mild climate and large onion to avoid pressure bruising.
• Cubicles should be done instead of leaving continuous battery enough space for ventilation on all sides.
One cubic meter of area capable of storing about 750 kg of onions.
Transport
onion populations are transported in bullock carts, trucks and tractor trucks and rail cars also are used for longer movement distance within the country. Onions are transported in ventilated vessels and sailing vessels / boats for export to Gulf countries and South-East Asia. Will also be awarded 3.5 million containers or 7 million for cargo ships.
… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … …
2.1 Pre-harvest Operations
The condition of the leaves of onion is a good indicator maturity and the general state of the bulb. onions should be stored should be allowed to mature before harvest and this happens when the leaves are bent just above the top of the bulb and fall. As a practical guide, farmers must make the sample counts on the number of bulbs, which have fallen more in a field, and where the percentage of bulbs, which have fallen, reaching about 70-80%, then the whole crop must be harvested. The collection could begin earlier, when 50-80% the caps have been passed, before it is possible to see the exposure of onion skins split the storage losses of meat in the optimum maturity, are generally more lower than those collected before its collapse tapas. Lamps generally mature within 100-140 days after sowing, depending on cultivar and climate. Ripe for harvesting onions after 35-45 days from sowing. Harvesting should be allowed to dry or cure and ripen in the sun for several days after lifting. Onions can produce up to 5-1 t.ha under growing conditions and good management.
2.2 The collection and transportation
Manual harvesting is the most common practice in most developing countries. This is normally done by prying the bulbs with a fork to loosen and pull the upper hand. In countries developed, especially in large-scale farms, mechanical harvesting is commonly used.
Collection techniques adopted are influenced by conditions weather during harvest. In areas where warm, dry weather occurs reliably, curing and bagging harvest can be done in the field (two of the collection phase). In more humid, temperate regions, mechanical harvesting and artificial heating and ventilation for drying are essential for the reliable production of bulbs High quality, large scale.
The following steps are followed for two stages of the onion harvest: (A) cutting the leaves (if necessary), (b) tripping, undermining onions and sieved to remove stones and clods, (c) roll the soil in the row to obtain a flat surface, (d) drying of the bulbs (rows) 8-10 days in the field; (E) turning the bulbs 1 to 2 times, (f) collection, screening and classification of hand, the overhead on a trailer or in boxes, and (G) of transport. For a phase of crop usually commercial potato harvesters have been adapted. After cutting the leaves of the crop is harvested immediately, screened, hand sorted and loaded onto the trailer. Because of the additional costs involved operations, the costs of labor for the harvest of two phases are 30-100% higher than a phase of crop. The main disadvantage of harvesting phase is the high energy consumption required for mechanical drying. Combined use of harvest, the standard working hours has been estimated at 2.7 to 2.9 to 1 for hr.ha stumble, 2.4-2.6-1 hr.ha for turning and from 8.9 to 11 hr.ha-1 (KTBL, 1993).
harvested bulbs are placed in containers (container basket) or tied in bundles and placed directly on the floor of a trailer for transport. These trailers can be pulled by an animal (like the donkey) or mechanical transport such as a tractor. Both systems packaging and transportation should be selected to ensure minimal handling damage occur. Hard surfaces should be cushioned with leaves, foam or other retarders appropriate force.
2.3 Curing and Drying
Both cure and dry the excess moisture from the outer layers of the bulb before storing. Dry skin provides a barrier to water loss and surface microbial infection, thereby preserving the main edible tissue in a fresh state. Drying also reduces shrinkage during subsequent handling, reduces the occurrence of outbreaks, and allows the crop to mature before eating fresh or long-term storage (Opara and Geyer, 1999). This dehydration process is sometimes called "cure", but the use of the word 'cure' for onion drying is quite inaccurate, since no regeneration of cells or wound healing occurs in other root crops such as yams and cassava. Drying reduces the weight of the bulb and as they are sold primarily on the basis weight, reaching the desired level of dehydration is critical. The weight losses of 3-5% are normal, dry conditions and up to 10% with artificial drying.
In the traditional small-scale operations, onion drying is carried out in the field in a process commonly called "strings." It is collection of the bulbs mature and laying them on their sides (in rows) on the soil surface to dry for 1 or 2 weeks. In warm, tropical climates, the bulbs should be stacked in such a way to reduce the exposed surface to minimize damage due to exposure to direct sunlight. In humid climates, the bulbs can take longer to dry and may develop higher levels of rot during storage. The side of the bulb in contact with moist soil or moisture also strains may develop brown or pixels, that reduce the quality of appearance and value. Obviously, success is weather dependent rows and therefore can not be relied on large-scale commercial activity onion production. The harvested bulbs for storage requiring a total of 14-20 days of maturation or drying before stored. harvested onions can also be placed on trays which are stacked to one side of the field to dry. In some tropical regions, the bulbs are united in groups the tops of wickerwork, which is then hung on poles in sheds to dry naturally.
harvested bulbs can also be taken directly from field and artificially dried, either in a shop, barn, barns, or in a dryer designed for it.
This method is often used when crops are stored in bulk, but can also be applied to the bags, boxes or containers. Under this method, the bulbs are placed in racks and heated air passes over the surface quickly of night and day bulbs [O'Connor, 1979; Brice et al., 1997]. Drying can take 7-10 days and is considered complete when the neck of the bulbs have dried and skins are tight and cry when held in hand. The level of humidity in the store is critical. Under high humidity, drying is delayed and infection yeast may increase.
However, if the relative humidity is very low (less than 60%), excessive loss of water and division of the lamp envelope may occur, resulting in losses in storage and reducing the value of the bulb. Place the onions in the wire mesh in conditions of good ventilation and air 30 ° C, 60-75% RH and 150 m³. h-1.m-3 is generally recommended for mechanical drying of onions.
2.4 Cleaning
The freedom of all impurities, that may substantially alter the appearance or eating quality is essential. Soil and other foreign materials must be removed and bad products should be discarded. Cleaning can be done with air or by manually removing unwanted materials on the surface of the bulb. Care must be taken to avoid injury in the bulb during these operations.
2.5 Packaging
Overview
Well onions containers must meet the following criteria: (a) enough strong to maintain the required weight of onion in the transport and storage conditions, (b) allow adequate ventilation for air around the bulbs to keep the relative humidity within the required range, and (c) in many cases, provide a means of showing the legal obligation and necessary trade information (Brice et al., 1999).
There are many traditional methods of holding the onions for the transportation and / or storage that do not fit the classifications of conventional packaging. These include "string of onions, shelves and loose aggregates' word of packing of the onion, the bulbs are linked through their Drinking to produce a lot of bulbs is also a form of packaging. This is suitable for transporting small quantities of harvest and during storage, bunches are hanging from the ceiling or special racks. Shelves for storage and handling of onions are made of wooden slats or metal mesh or frame of wood or metal, and usually in a fixed position with the loading and unloading bulbs in the store. Ventilation (natural or forced) is usually achieved by passing the air on the shelves. To achieve proper aeration of the outbreaks, the depth of the bulbs on the shelves are limited to 10 cm.
Onions are also stored in bulk loose (rather than containers) by heaping the bulbs directly on the floor or raised platform. Because they are not constrained, the bulbs during the rated load of the store to fill out the storage space. Bulk storage permits maximum utilization of warehouse space, and aeration is even easier to perform than the piles of bags or other rigid containers.
However, if the bulk storage is applicable, the retaining walls must be strengthened to store larger amounts of bulbs, and arrangements must be made before further marketing rebagging. It is also difficult to inspect regularly the bulbs under these storage conditions. Loose bulk handling of onion is the most suitable for large-scale operations where ventilation can be provided for long term storage. Soft cultivars (Which are also generally sweet) "Vidalia Sweets" should not be stored in bulk loose due to their high susceptibility to compression and impact damage.
Onions can be packaged and stored in a variety of containers such as boxes, cartons, bags, bulk containers, pre-packs, plastic bags, film, and stretch-wrapped trays. Packages generally contain 25 kg and above, especially for the transport field crops to store and / or during storage. The same bags 25 kg or smaller bags can be used to shop in the market. Decision on what type of container used depends on the size of the crop, the duration of storage and disposal requirements. One problem with onions packed in boxes, mesh bags and bulk containers is that if too large, and the flow pattern air tends to be more than through them. Under these conditions, the heat of respiration of the bulb results in a warm and humid in the middle of the pack, which can lead to decay or sprouting. To avoid these problems in major stores, the capital investment in origin may be very important.
Bags Onion
Sacks and nets used for packaging onions fall into three groups: (i) general use of jute bags, used for many agricultural products, (Ii) mesh bags and sisal fiber, (iii) open-mesh networks, usually of plastic and (iv) large bags, used as an alternative to boxes, which contain up to 1000 kg. jute bags are readily available in most developing countries, but its disadvantages include: (i) generally too great – can contain 100 kg of onions, so unwieldy and an increased risk of mechanical damage, (ii) light bulbs are not visible through the tissue, and difficult to monitor the condition during storage, (iii) there is some resistance to air flow when used in a gas store, (iv) difficult to label effectively, and (v) The recycled bags may encourage the spread of postharvest diseases.
sisal bags are made of hard fibers such as sisal and have a tissue open, with thick wire, spaced about 10 cm and 15 apart. The rough nature of the fiber provides a very stable tissue. These bags are similar to jute sacks, but will allow limited visibility of the onions and the impedance to air flow is lower.
open-mesh networks are the most widely used for the package of onions, and are usually red or orange in color. The elusive nature of plastics may result in the movement of the threads that allow for large holes that open. To overcome this problem, alternative networks for industrial production to mesh fully stable and strong bag. The main techniques are: (i) PVC extruded net by high density, (ii) of paragraph (Warp knitted) and the asymmetric structure, and (iii) special fabric weft threads are double, and twisted. It also breaks down slowly by sunlight, and should not be left outdoors for long periods before use. Compared with other types of bags, offer several advantages, including: (i) lightweight, small bulk when empty, (ii) generally available in sizes 12.5 and 25 kg, (iii) pretty good visibility bulbs, (iv) excellent ventilation, (v) health, (vi) the closure easy (string extraction rates only), (vii) and the mark of crops and marketing information can be printed in the middle of the bag for easy identification.
Rigid Packages
A range rigid container used for packing onions for transport, marketing, and storage (Opara and Geyer, 1999). Rigid containers are main courses (10-15 kg of onions each), boxes (25 kg) and silos (up to 1000 kg). These types of containers allows the segregation of different onion varieties or sources. Choice of packaging material is important as timber bins, for example, are susceptible to attack by termites and the elements during the offseason. Rigid containers are also expensive, require regular maintenance and a forklift is required to handle larger containers. When rigid containers are used for storage onion, building design is simpler than the large-scale bulk storage loose as reinforcement of retaining walls are not required to support bulbs. Management of the damage of the bulbs during filling and emptying can be high, but the damage is reduced during loading and unloading of the store compared to the loose management and bulk storage.
Stacking containers must be done carefully and ensure that the ventilation air is forced through the container lamps and not around them. One of the main advantages of rigid containers is to facilitate regular inspection of products, and when problems arose with stack, the affected area is often limited to a few trays, boxes or containers that can be more easily isolated and separated on the loose handling system bulk.
Pre-packs Onion
Onions are commonly sold in retail outlets in pre-packages with a capacity of 0.5 to 1.5 kg. Pre-packaged offers following advantages over the bulbs just in piles or bags of: (i) the price can be connected to produce, (ii) the compilation of a series of pieces in a single unit of sale may promote the sale of an amount greater than otherwise would be purchased, (iii) provides an odorless cleaning unit for the customer to handle, and (iv) reduces the time spent in the hotel. The use of weight / price labeller machines and bar code has reduced the need for fixing pack nominal pesos. In preparation for retail sale retail, the amount of product is measured by hand or machine and filled in the package. Then the actual weight and price and / or bar codes are automatically calculated and are printed on a label attached to the package.
This weight machining and labeling system packager assists in maintaining accurate records and avoid losses package due to incorrect weights. The three main types of onions are networks pre-packs, plastic bags, film, and stretch-wrapped trays
2.6 Bulk Storage
General requirements
The objectives of storage onions are available to extend the period of cultivation, to maintain quality optimal bulb and minimize the losses of physical, physiological and pathological conditions. The bulbs selected for storage should be firm and neck dry and thin. Dispose of thick neck bulbs because they are most likely to have high moisture content at optimum level for storage, which would Short conservation. Skin color should be typical of the variety. microbial infections such as Aspergillus niger occur during the production of onions, but they only develop in the bulbs during storage in the storage environment is conducive for growth. Before storage, crops must be cleaned and sorted, and all damaged or diseased bulbs removed. Careful harvest and pre-storage treatments with minimal mechanical stress are important to achieve a long storage period. Both storage temperature and relative humidity, and atmospheric composition affect the shelf life can be achieved. Several options are available for technology for bulk storage of onions, including storage under temperate climate, high temperature storage, the storage of direct harvesting and use controlled atmosphere (CA), shops. The recommended storage conditions in these systems are summarized below.
Storage temperature down
For a good low-temperature storage, good ventilation and low humidity in the range of 70-75% is essential. To maintain good quality crops, the period storage varies, but can be up to 200 days. For the maximum period of storage and minimal losses bulbs must be fully mature at harvest, and dry until the "neck" of the bulb is tight. For large-scale commercial storage, the onions are usually stored in refrigeration and conditions commonly recommended are 0 ° C with 70-75% RH. ventilation and periodically monitor the temperature and relative humidity in the store are needed to avoid fluctuations important environmental conditions. During the first days of storage at the fans should provide adequate air flow to remove water in the outer skin and to dry wounds. The high velocity air that is needed for a period of up to one week, until the skin of the upper layers of the onion bulk cracks. Excess moisture stores lead to the development of roots and promote decomposition, while higher temperatures will lead to germination and promote development of pathological disorders such as Botrytis rot (Thompson, 1982) Bulbs freeze below -3 ° C and a range of storage temperatures and relative humidities were recommended for safe storage of onions (Table 5). Spring (green) onion best store at about 0 ° C and high humidity (95%) (Table 6). The duration Maximum storage under these conditions varies from a few days to about three weeks. Ventilation must be carefully applied inside the tent to warm up required and the moisture levels and without causing water condensation on the surface.
Onion storage in high temperature
Onions can be stored at high temperatures over 25 ° C in a range of relative humidity (75-85%) than is necessary to minimize water loss.
The storage temperatures of 25-30 ° C has been shown to reduce germination and root growth compared with the storage of low temperature (10-20 º C). However, weight loss, drying of the bulbs, and rots occurred at high temperatures, making the system unprofitable for long periods of storage required for the marketing of onions with success (Thompson et al., 1972; Stow, 1975). In tropical climates, high temperature storage of onions is available both under ambient and heated storage conditions. Under these conditions, the ventilation must be carefully applied inside the tent to reach the required temperature and humidity levels.
'Harvest Storage Direct
The need to cure the onions may pose considerable problems in situations where the condition is unpredictable climatic conditions during the harvest period. To overcome these problems, the "system of direct harvest" has been developed and widely used, particularly by producers in the United Kingdom since the 1980s. The bulbs are harvested while green, capped, loaded into the warehouse, drying and curing system with controlled ventilation shafts, and later in storage long-term low temperature as required (Table 7). During stage I, removing excess moisture from the surface to get a good price high air flow, ignoring the relative humidity. Stage II is complete when the skin have been cured in the bulb. The proper control of storage conditions at different stages is crucial to the success of this system to maintain the necessary storage bulb quality.
A is used in combination with coldstorage to extend the storage life of onion. The recommended composition of air and temperature regimes are summarized in Table 8. General onions tolerate higher levels of CO2 and O2 of onions, and levels of CO2 and O2 mix required varies depending on the storage temperature (Table 9). Commercial CA storage of onion bulbs is limited in part because of the success variable and inconsistent effects on the quality of the bulb.
However, The high carbon dioxide (0-5%) and low oxygen levels (1-3%) in combination with the levels of low-temperature storage has been shown to reduce germination and root growth (Sealand, 1991; Hardenburg et al., 1990). The combination of CA storage (5% CO2, O2 3%) and refrigerated storage (1 ° C) also resulted in 99% of marketable onion bulbs considered after 7 months of storage, however, there was 9% weight loss (Smittle, 1989).
Onion response to CA storage varies among cultivars. Therefore, both experiments should be conducted under local conditions determine the appropriate level of gas composition suitable for the safe storage of local crops. CA storage usually increases the pungency of the cultivars feature. For the 'Sweet Viladia ", characterized by its low pungency and sweetness, the recommended storage conditions (Smittle, 1989): 1 º C, relative humidity 70-80%, 3% O2, 5% CO2, N2 92%, and the rate of ventilation-1.m3 5.m3.h onions.
2.7 Processing
onion bulbs are generally cut desired sizes and shapes with a knife. Many commercial devices are also available for chopping onions. In some prepared foods, onions are mixed with other ingredients to produce the desired flavor.
About the Author
Snowman Frozen Foods Ltd. is the first company in India to set up frozen and chilled food distribution system on pan India basis. India cold chain is in the best position to act as a single window logistics solution provider for our business partners offering the entire rang of integrated logistics cold chain etc.
