EFFECT OF PROCESSING ON NUTRITIONAL AND ANTINUTRITIONAL FACTORS OF MOONGBEAN CULTIVARS

Ordinary cooking of presoaked and unsoaked seeds of six cultivars of moongbean (Vigna radiata L.) lowered phytic acid, polyphenols, trypsin inhibitors and improved in vitro digestibility of protein and starch, and availability of Ca, Fe and Zn when compared to unprocessed seeds. However, the effect was more pronounced on ordinary cooking of presoaked seeds followed by cooking of unsoaked seeds and presoaked seeds alone. A significant increase in vitro digestibility of protein (34–48%), and starch (31–62%) may be ascribed to the reduced content of phytic acid (45–65%) polyphenols (34–70%) and trypsin inhibitor activity (42–55%) after ordinary cooking of presoaked seeds of moongbean cultivars. Therefore, ordinary cooking of soaked seeds was the most effective treatment in improving the nutritional quality of moongbean.     

EFFECT OF PROCESSING TREATMENTS ON NUTRITIONAL AND ANTINUTRITIONAL CONTENTS OF GREEN GRAM

High‐yielding varieties of green gram (Vigna radiata L.), namely Asha and MH1K‐25 contained a significant amount of antinutrients. Various processing and cooking methods, namely soaking, dehulling, ordinary cooking, pressure cooking and sprouting, decreased the level of antinutrients and improved in vitro digestibility of protein and in vitro availability of calcium, iron and zinc observed. The beneficial effect was more pronounced with pressure‐cooked and soaked seeds followed by ordinary cooking, sprouting (24 h), dehulling and soaking in both cultivars. A significant increase in in vitro protein digestibility (34–35%), in vitro availability of Ca (59–61%), Fe (52–56%) and Zn (62–67%) may be ascribed to the reduced content of phytic acid (35–39%), polyphenols (41–42%) and trypsin inhibitor activity (69–70%). Pressure cooking was the most effective treatment in improving the nutritional quality of green gram.     

EFFECT OF COMPOSITION OF GLUTHNIN SUBFRACTIONS ON RHEOLOGICAL PROPERTIES OF WHEAT

Gluten extracted from defatted flours of cv. Aubaine (extra‐strong), Hereward (strong) and Riband (weak) was separated into five different fractions (R2 to R6) by sequential centrifugation and addition of sodium chloride. A seven‐minute mixing time was used to carry out fractionation on the basis of depolymerization of glutenin macropolymers (GMP). Depolymerization of GMP occurred at much higher rates in dough of the weak cultivar compared to the strong and extra‐strong cultivars. Polypeptide compositions of different ghttenin fractions were determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis under reduced and non‐reduced conditions, followed by densitometric scanning of stained patterns. The amount of HMW‐glutenin subunits decreased and LMW‐glutenin subunits increased correspondingly in each cultivar with the fractionation from R₂ to R₆. The rheological behavior of the fractions was analyzed by small deformation rheological tests (strain sweep and frequency tests). The high molecular weight fraction (R₂) from extra‐strong wheat had a higher vahte of G' and a lower tan δ value as compared to strong and weak bread‐making wheats. The moduli of HMW glutenin fractions (R2 and R3) were frequency independent and promoted the network properties, whereas moduli of LMW glutenin fractions were frequency dependent and gave rise to a plasticizing effect. Therefore, it was concluded from the present studies that HMW‐glutenin subunits are not the only factors governing good bread‐making quality but their proportions in relation to low molecular weight glutenin subunits is equally important in sinking a balance between viscous and elastic properties essential for bread making performance.     

EFFECT OF SOAKING AND GERMINATION ON NUTRIENT AND ANTINUTRIENT CONTENTS OF FENUGREEK (TRIGONELLA FOENUM GRAECUM L.)

Fenugreek seeds (raw, soaked and germinated) were analyzed for their chemical composition. Raw fenugreek seeds contained higher amount of dietary fiber 46.50% followed by 42.12% in soaked seeds and 32.50% in germinated seeds. Soaking reduced the level of total soluble sugars, reducing sugars, nonreducing sugars, dietary fiber and improved the protein and starch digestibility and availability of minerals. Germinated fenugreek seeds had significantly higher contents of total protein (29%) and total lysine (6.48 g/100 g protein) compared to unprocessed seeds. Germination decreased dietary fiber and starch thereby raising the level of sugars. In vitro starch and protein digestibility and availability of Ca, Fe and Zn were also increased appreciably due to reduction in antinutrient contents (phytic acid and polyphenols) after 48 h germination.