Effect of soaking and cooking on nutritional quality and safety of legumes

Abstract

PurposeLegumes are widely grown and are consumed as a source of plant protein throughout the world. They rank second after cereals with respect to their consumption order. Legumes have anti‐nutritional factors which make their uses limited. This study aims to check the effect of soaking and cooking on the anti‐nutrient contents and nutritional quality of the legumes.Design/methodology/approachFive legumes (white kidney bean, red kidney bean, lentil, chickpea, and white gram) frequently used by the masses were selected for soaking and cooking trials. Legumes were tested for their weight, volume, density, swelling capacity and water absorption capacity before soaking and cooking. Legumes were soaked in simple water, 2 per cent sodium chloride solution, acetic acid and sodium bicarbonate and cooked in a beaker with 1 : 5 seed water ratio to uniform soft mass. After soaking and cooking, legumes were tested for anti‐nutrients (phytic acid and tannin) and their nutritional quality.FindingsThe statistical analysis of the study results revealed that dark colour legume (red kidney bens) has a high level of phytic acid and tannin compared with light colour (white kidney beans and white grams). Soaking and cooking of legumes result in significant reduction in phytic acid and tannin contents. Maximum reduction of phytic acid (78.055) and tannin (65.81 per cent) was found for sodium bicarbonate soaking followed by cooking. These treatments also result in a slight reduction in nutrients such as protein, minerals and total sugars.Practical implicationsSoaking and cooking of legumes reduce their anti‐nutrients; phytic acid and tannin significantly. These treatments may be used domestically as well as commercially to increase the nutrients' availability from legumes to meet the problem of protein and minerals deficiencies.Originality/valueAlong with water different soaking solutions which are easily available in the market were used to test out their effect on the nutritional quality and safety. These may be used by the common people to raise their nutritional status.

Modification of local diets to improve vitamin a, iron and protein contents for children aged 6 to 23 months in Kagera, Tanzania

“…This hindered bioavailability of the nutrients such as iron due to presence of phytate. Similar cases were reported from other studies [16,17,24,25] where they observed that soaking beans reduced phytate and resulted in improved bioavailability of iron. Cooking beans for a long time at high temperatures can destroy protein [17].…”

Physiochemical and nutritional attributes of raw and soaked seeds of chickpea (Cicer arietinum L.) genotypes

“…The reduction in protein content after soaking was found to be 18.69% in chickpea genotypes. Huma et al, (2008) reported that reduction in protein content (14.78 -21.83 %) after cooking the presoaked legumes might be attributed to partial removal of essential as well as non -essential amino acids with other nitrogenous compounds formed as a result of chemical degradation of protein into water soluble amino acids.…”

Phytic acid and mineral micronutrients in field-grown chickpea (Cicer arietinum L.) cultivars from western Canada

“…Other researchers report 9-18 mg/g PA for Weld-grown chickpea in Spain [31,32], 5.8-10 mg/g for Weld-grown chickpea in Egypt [22], 8.2 mg/g in Brazil [33], 2.3-6 mg/g for Weldgrown chickpea in Pakistan [34], 18 mg/g for Weld-grown chickpea in northern USA [35], and 9.8 mg/g in Weldgrown chickpea cotyledons from India [8], all from diVerent extraction methodology.…”