?AVAILABLE AND UNAVAILABLE CARBOHYDRATE CONTENT OF BLACK GRAM (VIGNA MUNGO) AND CHICK-PEA (CICER ARIETINUM) AS AFFECTED BY SOAKING AND COOK- ING PROCESSES

Abstract

The effects of soaking (Tap water, sodium bicarbonate solution) and cooking in tap water were investigated on available and
unavailable carbohydrate contents and starch digestibility of black grams and chick-peas. Available carbohydrates including
total soluble sugars, reducing sugars, non-reducing sugars and starch contents of these two legumes decreased to various
extents as a result of soaking and cooking. From 3.43 - 25.63% total soluble sugars and 4.26 - 22.70% starch contents were
lost on soaking black grams and chick-peas in tap water and sodium bicarbonate solution. Maximum amounts of total
soluble sugars (28.43 - 59.64%) and starch contents (29.93 - 67.40%) were lost on cooking the water and alkali soaked
legumes. However, these losses were comparatively less in case of water soaking process. Soaking and cooking processes
also brought about some changes in the profile of unavailable carbohydrates of black grams and chick-peas. Soaking in
sodium bicarbonate solution led to an appreciable increase of hemicellulose (42.50 - 54.31%) and NDF (28.69 - 30.68%)
but not in legumes soaked in tap water. However, cooking process caused reduction in NDF (19.25 - 41.04%), ADF (5.48
- 25.31%), cellulose (12.88 - 28.42%) and hemicellulose (31.86 - 59.37%). Lignin contents of these legumes increased to
some extents on cooking whereas it remained unchanged as a result of soaking . Starch digestibility of black grams and chick
peas was markedly improved after cooking. However, no appreciable improvement in starch digestibility was observed
after soaking these legumes in tap water or alkaline solution.