Dehydrated potato products Introduction Preservation of foods by drying is perhaps the oldest method known to man. Drying results in the lowering of moisture content leading to lesser chances of microbial growth. As a result, the product has a longer shelf life. The reduction in moisture content is accompanied by a reduced bulk which facilitates storage, transportation and packaging. Dehydrated potato chips are the most common processed potato product in the rural and semi-urban areas in India. Dehydrated chips have longer shelf life at room temperature and can be stored easily. Solar dehydration of potatoes is very popular in several states like Maharashtra, Gujarat, U.P. and M.P. and, remains a viable alternative to expensive and sophisticated potato processing technology.

Objectives After completing this lesson, you will be able to : Understand the importance of dehydration in potato and the products which can be made by dehydration.

Dried Potato Slices Dried potato slices are also known as raw chips. This is the most popular dehydrated product of potato. Potato slices can be dehydrated in the sun, stored and, fried and consumed when required. Raw chips are prepared at home by housewives and also by small scale manufacturers. The housewives simply hand peel the potatoes, cut them into slices and then boil the slices in water for 5-8 minutes.

Dried Potato Slices Contd.. Kufri Frysona The slices are dried in the sun till they become brittle. Small scale food processors generally use electrically operated peelers and slicers to make 1-2.5 mm thick slices of potatoes. These slices are washed in cold water to remove adhering starch. The slices are then blanched in hot water (80-90ºC) containing potassium metabisulphite. The blanched slices are then dried in the open, on polythene sheets.

Potato Flour Potato flour can be used in combination with other cereal and pulse flours for preparation of a number of products as per the desired taste. Gluten-free and rich in starch, potato flour is used by the food industry to bind meat mixtures and thicken gravies and soups. Some products like biscuits, cake, bhujia, paratha, etc. can be made. For the preparation of potato flour 1kg potatoes are taken in a container, 2 litres of water is added in it along with 10g of potassium metabisulphite. The potatoes are boiled, peeled and mashed after cooling and the mashed mass is spread on a plate or tray for drying in an oven at 80°C until fully dry. The dried content is ground to get a fine powder, sieved and stored for future use. 1 kg of potatoes yield about 200 g of potato flour.

Potato Flakes & Granules The process of making flakes and granules is similar in several ways and for the purpose washed potatoes are peeled using steam peelers. The potatoes are heated in steam under pressure, the pressure is released quickly, potatoes are cooled and the skin is removed using dry peelers. The peeled potatoes are washed and trimmed and are cut into slices of about 1-2mm thickness. The slices are then cooked in two stages; at first they are heated at 70C for 20 minutes and cooled for 15 minutes in water at 12C. They are then cooked at 100C for 30 minutes. The cooked slices are mashed and passed through a perforated plate. The mash so obtained is dried on a roller drier. The drier is a hollow roller which is heated by steam. A layer of the mash is applied with the help of feed rolls. The moisture in the mash evaporates due to the heat. The dry layer is removed as a sheet and broken into flakes. The flakes have a moisture content of about 6-7% and are generally packed in laminated packaging material with nitrogen.

Potato Flakes & Granules Contd.. The process of preparing granules is identical to that of flakes till cooking. Cooked slices in this case are mixed with granules to reduce the moisture content. The material is cooled for 1 hour at 15-20C and is dried by air at a temperature of 130- 150C to a moisture content of 12-15%. It is then sieved, and the portion between 0.18- 0.25mm is used for adding back to cooked slices. The rest is dried to a moisture content of 6-8% and packed as done for flakes. Starting with 100kg potatoes containing 22.5% dry matter, one can obtain a yield of about 18kg of flakes or granules.