The in vivo glycaemic responses to six cereal-based foods traditionally consumed in South India were evaluated in patients with non-insulin-dependent diabetes mellitus (NIDDM) and healthy volunteers. All foods contained 50 g carbohydrate and were compared with a 50 g glucose load. Also studied were the in vitro starch digestibility and nutrient composition of the foods. The postprandial responses to the foods at 30, 60 and 120 min were significantly (P Ͻ 0⋅05) lower than those to the reference glucose, in both groups. The peak glucose responses for three foods, i.e. chapatti, idli and poori, occurred 60 min postprandially in both groups. The glycaemic index (GI) values ranged from 67 to 90 in NIDDM and from 44 to 69 in healthy subjects with no significant differences within the groups. Significant relationships were observed between peak responses and area under the curve for foods in patients with NIDDM and in vitro rate of starch hydrolysis (r 0⋅83, r 0⋅85, P Ͻ 0⋅05). The GI values predicted using in vitro data were found to be similar to the GI values observed in patients with NIDDM. The GI concept is useful for identifying foods in the habitual Indian diet with attributes of the desired glycaemic effect such as delayed peak rise and low area under the curve.

The effect of processing on the total dietary fibre (TDF) insoluble (IDF) and water-soluble (SDF) fractions as well as total (TS), available (AS) and resistant (RS) starch were studied in three legumes, viz. bengalgram (Cicer arietinum L.), Cowpea (Vigna unguiculata) and greengram (Vigna radiata). The processes studied were fermentation, germination, pressure-cooking and roasting. The dietary fibre (DF) content and its components were determined using the enzymatic-gravimetric method. The TS content was determined by the enzymatic method after solubilization with KOH. The DF content ranged from 23.2 to 25.6 g/100 g in the raw and 16.0 to 31.5 g/100 g in the processed legumes. All the processing treatments significantly decreased the SDF content and increased the IDF content of all the three legumes. The mean TS, AS and RS content of the raw legumes were similar, 46.9, 36.7 and 10.2 g/100 g respectively. AS content of all the legumes was reduced by the processing treatments, except pressure cooking. Correspondingly, higher amounts of RS were observed in the processed legumes, except pressure cooked, resulting in an increase in the TDF content.

Nutritional quality of the castor meal protein isolate detoxified using boiling and lime cum heat treatments was evaluated in experiments with rats. Chemical scores of both the treated isolates were similar, threonine being the first limiting amino acid. The calculated nutritional indices (essential amino acid index) and PER were higher for the boiled isolate (1.3) than that was for lime-cum-heat treated (0.86). Though, necropsy examination of organs did not reveal any abnormalities, histopathological changes were observed in the organs-liver, kidney, intestine that could be attributed to the deficiency of essential amino acids in the detoxified castor protein isolates.

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SummaryThe effect of processing treatments on the rate of starch digestibility in three legumes, viz., bengal gram (Cicer arietinum L.), cowpea (Vigna unguiculata) and green gram (Vigna radiata) was studied using an in vitro dialysis system. The processes studied were fermentation, germination, pressure cooking and roasting. The released sugars measured as glucose equivalents after 3 h digestion were expressed as digestibility index (DI). All the processing treatments except roasting, increased the rate of starch digestibility in all the three legumes. Subsequent cooking of the gerniinated/fermented legumes lead to a further increase in starch digestibility. The results of the study indicate that 'slow release' property of legumes is heat labile and that loss of this property is independent of macro-nutrient and starch content.