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