Effect of Domestic Processing and Cooking on In Vitro Protein Digestibility of Moth Bean

Effect of thermal processing on protein solubility of green gram (Phaseolus aureus) legume cultivars

Green gram legume cultivars were analyzed for their protein solubility profile by fractionation in the raw form and also after heat processing. The results indicated that globulin fractions, which are present in major amounts that ranged from 79.5 to 85.4 % significantly decreased after the heat treatment. This decrease was accompanied by a significant increase in the glutelin-3 fractions. The prolamine contents did not vary considerably after processing. The protein and non-protein nitrogen contents ranged from 22.6 to 26.2 % and 2.3 to 2.7 % in the legume cultivars, respectively. The antinutritional factors like total polyphenol and phytic phosphorous were also determined. The accumulation of polyphenols was in the seed coat portion of the legume where as that of phytic phosphorus was in the cotyledons. SDS - PAGE profiles of all the three green gram cultivars had five major polypeptides (molecular weight 15, 18, 20, 45 and 60 kDa) in the total protein composition. Wide variation in electrophoresis pattern was observed after heat processing. Thermal treatment increased the insoluble protein fractions and eliminated the minor polypeptide bands below 14.3 kDa in the green gram cultivars.

Phytic acid, in vitro protein digestibility, dietary fiber, and minerals of pulses as influenced by processing methods

The objective of this project was to determine the effect of various types of processing on selected nutrition related parameters of commonly consumed Indian pulses and soybean. Germination reduced the phytic acid content of chickpea and pigeonpea seeds by over 60%, and that of mung bean, urd bean, and soybean by about 40%. Fermentation reduced phytic acid contents by 26-39% in all these legumes with the exception of pigeonpea in which it was reduced by more than 50%. Autoclaving and roasting were more effective in reducing phytic acid in chickpea and pigeonpea than in urd bean, mung bean, and soybean. Germination and fermentation greatly increased the in vitro protein digestibility (IVPD). IVPD was only slightly increased by roasting and autoclaving of all legumes. Germination and fermentation also remarkably decreased the total dietary fiber (TDF) in all legumes. Autoclaving and roasting resulted in slight increases in TDF values. All the processing treatments had little effect on calcium, magnesium and iron contents.

Effect of domestic processing on the cooking time, nutrients, antinutrients and in vitro protein digestibility of the African yambean (Sphenostylis stenocarpa)

The effects of processing (soaking, dehulling, fermentation and heat treatment) on the cooking time, protein, mineral, tannin, phytate and in vitro protein digestibility (IVPD) of the African yambean (AYB) were examined. The cooking time ranged from 90-155 minutes. Soaking reduced cooking time by about 50 percent. Soaking for 12 hours was the most appropriate to reduce cooking time, tannin and phytate levels. It improved in vitro protein digestibility (IVPD). Prolonged soaking (24 hours) decreased calcium (Ca) and iron (Fe) values by 19 percent and 35 percent, respectively. Dehulling showed that Ca, Fe, magnesium (Mg) and zinc (Zn) were concentrated in the seed coat of the AYB. The seeds soaked and dehulled retained Mg and Zn. Dehulling reduced tannin but had no significant effect on phytate and the IVPD of the AYB except for seeds soaked for 12 hours before dehulling. Soaking for 24 hours before dehulling significantly increased crude protein content by 16 percent (p < 0.05). Blanching and roasting increased the IVPD by 8-11 percent. Fermentation had no effect on the crude protein, Ca, Fe, Mg and Zn but significantly reduced phytate content of the AYB. Fermentation had no advantage over heat treatment with respect to improving the in vitro protein digestibility of the AYB.

The nutritive quality of maize-soybean (70:30) tempe flour

The nutritive quality of maize-soybean (70:30) tempe flour manufactured by fermentation with Rhizopus oligosporus: Rhizopus orysae (1:1) was determined using weanling rats. Mould fermentation of maize-soybean mixture did not significantly affect its proximate composition. It increased the content of reducing sugars, total acids and aminonitrogen by about 43, 195 and 482 percent, respectively, and decreased phytate content by 46 percent. In vitro iron absorption for maize flour and maize-soybean tempe flour was 2.46 and 5.51 percent, respectively. Protein Efficiency Ratio (PER) and Net Protein Ratio (NPR) for maize-soybean tempe flour and skim-milk diets were 2.71 and 2.96, respectively, for PER, and 3.31 and 3.51, respectively, for NPR. In vivo protein digestibility of the two products was 95.0 and 98.0 percent, respectively.