1. By-product Utilization in Potato
Introduction
Potato is one of the most important staple crops for human consumption along with wheat, rice and corn. Mostly potatoes are processed into a variety of products such as mashed potatoes, chips, fries and deep frozen and dehydrated products. Waste products from potatoes processing are a big disposal problem. Approximately 35% of the total processed potato crop is discarded as a waste during processing. This waste ferments rapidly and adds to the pollution problem if not properly utilized. The total world potato waste is estimated to 12 million tones per year. Abrasion which is used for potato chips, contribute 10% loss. A substantial portion of the potato crops proves unusable for seed, table stock or processing. The utilization of by-products contributes to reduced amount of waste and thus to sustainable production.

2. Objectives After completing this lesson, you will be able to :
Know about the waste utilization in potato.

3. Protein Recovery & Its Utilization
Potato protein is rich in lysine and contains methionine and cystine as the limiting amino acids. However, the nutritive quality of potato protein is comparable to that of whole egg and waste from potato processing plants can be used for feed, food, and useful products. European starch processing plants are recovering potato protein concentrates as animal feed. Single-celled protein are unicelled organisms grown on an industrial scale specifically for their protein content under controlled fermentation conditions. Cultivation of mycelial fungi on potato processing industry waste is useful as they contain a complex of hydrolytic enzymes that eliminate the necessity of hydrolyzing potato substrates before culturing. Penicillium gigitatum 24 P grown on potato processing wastes increased the biological value of the protein preparations because of their high contents of unsaturated fatty acids and vitamin F. The potato distillery byproducts obtained from French fry industry waste after alcoholic fermentation contains fair amounts of crude protein (17.6 to 25.3%).

4. Animal Feed
Potato waste is an excellent source of energy for feeding cattle. It has energy values similar to corn and barley while being low in calcium and protein. Potato peel, a waste by-product of potato processing is a good source of fibre and polyphenols that exert antihyperglycemic effect in rats. Potatoes consist of 80% water and water content of the peeling waste is more than 85%. Generally potato waste is mixed with other feed so that the dry matter content of mixture is adequate.

5. Animal Feed Contd…
Potato peel, cull potatoes, and products derived from processing wastes have been utilized for animal feed. Fermented potato waste is an excellent nitrogen source for ruminant animals. Potato processing waste (PPW) can replace corn and barley (Hordeum vulgare L.) grain and it does not have any negative effects on growth of beef cattle or meat quality, and the diets containing up to 80% PPW increased efficiency of animal growth per unit diet intake. Making potato silage from the wastes is one way of utilizing it for animal feed as practiced at several places.

6. Other Uses
Potato waste, when mixed with wheat starch milk, can give an adhesive with improved properties. Pectin can be obtained after the removal of residual starch from waste by heating in water and subsequent treatment with glucoamylase. The starch product, obtained by drying the debris recovered from peeling potatoes, is recommended for use in drilling muds. Medical and biological sciences are researching uses of solanine, chaconine, and leptine extracted from potato wastes. Chlorogenic acid (CGA), a naturally occurring phenolic compound found in fruits and vegetables, is readily extractable from potato peels. The CGA, the major phenolic in potato peels, can be extracted from potato wastes with boiling water and is as good an antioxidant as the commonly used antioxidant butylated hydroxyanisole (BHA). By-products of potato processing were considered as a source of extraction of L-ascorbic acid that can be used in an agar gel. Potato starch, derived from processing, has also been converted to glucose and then to lactic and citric acids and used to construct biodegradable plastic.