ONION DEHYDRATION-POWDER, FLAKES/KIBBLED AND MINCED

Dehydrated vegetables are being increasingly used as they retain their culinary quality and palatability, and bring about economy in storage space and transport cost. Besides, there is optimum utilization of the product during the glut season, and saving of packaging material and tinplate. Dehydrated onion is used extensively in overseas countries as a condiment. Efforts are also being made for export of dehydrated onions, which is being produced by several manufacturers. This standard is intended to help in the quality control of dehydrated Onion. Dehydrated Onions have been produced in small quantities since the nineteenth century is dehydrated onions were supplied to British naval expeditions in the mid-nineteenth century and dehydrated onions have been produced in sizable quantities during subsequent wars, primarily for consumption by armed forces, but also for civilian use. Since the quality of these products when rehydrated compared unfavourably with fresh vegetables or other types of processed onions, their usage declined rapidly after each war. However the processing techniques employed in the production of dehydrated onions have been improved greatly since world war II, particularly since the late nineteen fifties, and as a result the quality of dehydrated vegetables has much improved. At the same time the demand for convenience foods have been increasing and dehydrated onions have benefited accordingly. The main advantages of dehydrated onions are that they are easy to store, being lighter in weight and smaller in bulk than fresh or other processed onions, they are cheap to pack compared with conned goods, they do not require refrigerated storage as do frozen onions and the contents of a container can be used some time after opening provided they are not rehydrated. The newest dehydration process appears to be a variation on the air-drying process and is based on the principle of vapour pressure differentials, using air circulated around the onions at relatively low temperatures to `sweat’ the water from the food. It is reported that this method of dehydration prevents a crust forming on the outside of the pieces of food and that the low temperatures have less effect on flavour, texture, colour and vitamin contents of onion than do the higher temperatures used in conventional hot air-drying methods. When establishing a dehydration industry considerable thought should be given to the procurement of fresh onions for dehydration. In most countries onions for dehydration are grown almost exclusively on contract to the processors. The contract are made up of a year in advance and cover such aspects as acreage, planting periods, varieties of onions, field inspection, stage of maturity for harvesting, delivery dates, grading and prices. To operate a dehydration plant efficiency, a constant supply of onions is required and this involves considerable organization buying in supplies of fresh onion market is rarely practicable since varieties grown for the fresh market may be unsuitable for processing and continuity if supply cannot be assured. It is usually found that specialization in processing one or two types is more profitable then production of wide range of dehydrated onions. Ideally a dehydration factory should handle only one type of onion over long periods, so as to avoid the necessity of cleaning down all the machinery and altering the grading and cutting setting etc. when changing from one vegetable to another.