TEXTURAL CHANGES OF GREEN GRAM (PHASEOLUS AUREUS) AND HORSE GRAM (DOLICHOS BIFLORUS) AS AFFECTED BY SOAKING AND COOKING

The soaking and cooking effects on the texture of whole as well as dehulled split green gram and horse gram were studied using universal texture machine and scanning electron microscopy. The hardness values of raw whole legumes of green gram (67.5–69.9 N) and horse gram (186.5–245 N) decreased to 45.3–57.4 N and 137.8–207.8 N, respectively, after 1 h soaking. At respective cooking times (CTs), the force required to 50% compression was 1.4–3.5 and 8.1–11.7 N for the whole legumes, and 3.8–5.3 and 13.1–13.8 N for dhal (dehulled split cotyledon). Both dhals showed higher hardness values in raw form compared with whole legumes. Materials leached out from the whole grains of green gram and horse gram accounted for 19.09–21.53% and 18.98–21.15%, whereas for dehulled split cotyledons they were 20.59–26.34% and 17.85–20.33%, at their respective CTs. Texture values for legumes under various experimental conditions were modeled using central composite rotatable design coupled with response surface methodology. PRACTICAL APPLICATIONS The cooking quality of legumes which is dependent upon textural softness is very important in terms of consumer acceptance. This information on the effect of soaking and cooking on the texture of the two legume cultivars studied using universal texture machine will be useful in understanding the basic differences in genotypes and inherent properties. The models presented here will be of help to demonstrate the relation of force–deformation curves and textural changes of grains during various processing steps. This study on legume structural changes will also lead to good knowledge base, which could be utilized by food industries to aim at new and innovative products.