MSc

Legume grains are generally processed before consumption depending on the cultural and taste preferences. In India the most common domestic methods of processing of legumes include soaking, soaking and dehulling, milling and germination. These methods have been reported to be beneficial for enhancing the nutritive value of various food legumes, by reducing the antinutritional factors and enhancing the bioavailability of minerals.

Bioavailability is the degree to which food nutrients are available for absorption and utilisation in the body. Extractable minerals in a food are those which are soluble in 0.03 N HCl, the concentration is found in human stomach. The amount of HCl extractable minerals indicates an index of their bioavailability from foods. In the present study an attempt was made to estimate the HCl extractability of minerals from pulses.

Three legumes such as bengal gram, green gram and horse gram were selected and subjected to various processing methods such as soaking, soaking and dehulling, milling and germination and two cooking methods such as ordinary cooking and pressure cooking.

Among the processing and cooking methods studied, germination for 36hrs and 5mts pressure cooking was the best method for improving the extractability of minerals like calcium (67.63%), iron (39.75%), phosphorus (55.08%) and zinc (70.41%) in bengal gram. In green gram and horse gram maximum calcium (29.78% and 52.35% respectively) and phosphorus (56.66% and 52.13% respectively) extractability was observed by this method. This method is also suitable for reducing the tannin content in bengal gram (73%), green gram (35%) and horse gram (90%). Germination for 36hrs and 30mts ordinary cooking can cause a further increase in iron extractability. In green gram iron extractability (70.19%) and in horse gram iron (70.23%), potassium (49.53%) and zinc (50.83%) extractability was increased by this method. Germination for 24 hrs and 30mts ordinary cooked sample showed maximum zinc (76.01%) extractability in green gram. The milled and pressure cooked sample showed a maximum potassium extractability in bengal gram (48.23%) and green gram (50.69%). Milled and cooked samples showed a considerable reduction in phytic acid and crude fiber content.

Over all, the processing and cooking methods improved the HCl extractability of minerals from pulses. Maximum improvement was brought about by germination (24 and 36hrs) followed by pressure cooking and ordinary cooking and milling. As these processing methods are inexpensive in terms of time, energy and fuel saving, these methods can be used in household processing of legumes especially in developing countries like India where legumes are an integral part of the daily meal pattern.