Domestic processing effects on available carbohydrate content and starch digestibility of black grams (Vigna mungo) and chick peas (Cicer arietium)

Domestic processing effects on available carbohydrate contents and starch digestibility of black grams and chick peas were investigated. The food legumes were soaked in tap water and alkaline solution of sodium bicarbonate at 30 and 100 °C for 1–2 h before cooking under pressure. Total soluble sugars, reducing sugars and starch contents of black grams and chick peas were 9.64% and 9.83%, 0.78% and 0.83%, 43.0% and 44.3%, respectively. All these available carbohydrate contents of black grams and chick peas were reduced to various extents as a result of soaking and cooking. At 30 °C, 4.46% of total soluble sugars, 3.84% of reducing sugars and 6.86% of starch contents were reduced on soaking the black grams in tap water for 1 h. Available carbohydrate contents were further reduced when soaking time and temperature of the food legumes was increased before cooking. About 3.43–25.0% of total soluble sugars and 4.26–22.7% of starch contents were lost on soaking black grams and chick peas in tap water and sodium bicarbonate solution. Maximum amounts of total soluble sugars (28.5–59.6%) and starch contents (29.9–67.4%) were lost on cooking the water- and alkali-soaked food legumes. However, these losses were comparatively less with the water soaking process. Besides these losses, starch digestibilities of black grams and chick peas were markedly improved as a result of cooking. However, no appreciable improvement in the starch digestibility was observed after soaking these food legumes in water or alkaline solution.