Date of Publication :20th April 2018

Abstract: Onion (Allium cepa L.) is considered to be one of the most important crops in all countries. It is the round in shape edible bulb. Red, white and gold onions represent the most common varieties of this species. It is widely used as seasoning in foods. Onion is a strong-flavoured vegetable used in a wide variety of ways, and its characteristic flavour (pungency) or aroma, biological compounds and medicinal uses are mainly due to their high organo-sulphur compounds. Dehydration process removes moisture content of food. The advantage of dehydrated foods is that low moisture content slows down or prevents the growth of microorganisms that causes spoilage reactions and increases its storability. Dried onions are a product of great significance in world trade produced either as flaked, minced, chopped or powdered forms. Various drying methods being used for dehydration of onion such as open air drying, solar drying, convective air drying, fluidized bed drying, vacuum microwave drying, infrared drying, microwave freeze drying and osmotic drying. The commonly used dehydration method is open air sun drying and solar drying demands longer drying time, high temperature and affected by daily fluctuation of weather and thereby making it difficult to maintain the product moisture content and quality properly because of air-borne dirt and dust so other drying methods are good for dehydration and to maintain the quality of product. The color and flavour of dried onions are considered the most important quality attributes affecting the degree of acceptability of the product by the consumer. Hence colour and flavor retention of onion during drying is most important attributes for the onion dehydration

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