Jamuna Prakash

Rice bran proteins: Properties and food uses

Rice bran, a good source of protein and fat, is at present underutilized as a food material. The potential of producing rice bran at the global level is 27.3 million t. The presence of enzyme lipase in rice bran causes rapid deterioration of oil to free fatty acids and glycerol. Various stabilization techniques involving heat treatment, low-temperature storage, chemical treatment, control of relative humidity during storage, and simultaneous milling and extraction were evolved to inactivate lipase. Multiple forms of rice bran lipase have been identified. Fractional classification of proteins reveals a high percentage of albumins and globulins. Proteins can be extracted from full-fat or defatted rice bran by alkaline extraction and acid or heat precipitation. Extraction procedures influence the protein content of concentrates, which ranged from 19.4 to 76.1% in concentrates from full-fat rice bran and 17.5 to 85.0% in concentrates from defatted rice bran. The PER of rice bran ranges from 1.59 to 2.04 and that of protein concentrates from 1.99 to 2.19. Available lysine contents of protein concentrates ranged from 54 to 58.8%. The essential amino acid profiles of protein concentrates indicate that threonine and isoleucine are limiting amino acids. Various functional properties of rice bran protein concentrates have also been investigated that are known to be influenced by drying technique and stabilization treatment of rice bran. Rice bran has been used in food as full-fat rice bran, defatted rice bran, and in the form of rice bran oil and protein concentrates. Full-fat and defatted rice bran have been used in bakery products, breakfast cereals, wafers, as a protein supplement, binder ingredients for meats and sausages, and as a beverage base. Incorporation of protein concentrates have been studied in bread, beverages, confections, and weaning foods.

Influence of antioxidant spices on the retention of β-carotene in vegetables during domestic cooking processes

Abstract Considerable amounts of β-carotene were lost during the two domestic methods of cooking commonly used, namely, pressure cooking and open pan boiling, the loss ranging from 27 to 71% during pressure cooking and 16–67% during boiling for the four vegetables examined in this study. Pressure cooking of green leafy vegetables resulted in a greater retention of this provitamin. In the presence of red gram dhal, which is a common ingredient in the diet, there was an underestimation of β-carotene due to poor extractability. Inclusion of acidulants—tamarind and citric acid-along with these vegetables brought about some changes in the level of retention of β-carotene. The antioxidant spice turmeric generally improved the retention of β-carotene in all four vegetables studied. Onion also had a similar effect. The combinations of acidulants and antioxidant spices also improved the retention of β-carotene during cooking. This effect seemed to be additive in the case of processing of amaranth by boiling.

Nutritional quality of microwave-cooked and pressure-cooked legumes

Eight whole legumes, namely Bengal gram (Cicer arietinum), broad beans (Vicia faba), Cowpea (Vigna catjang), field beans (Dolichos lablab), green gram (Phaseolus aureus Roxb), horse gram (Dolichos biflorus), lentils (Lens esculenta) and French beans (Phaseolus vulgaris), were cooked under pressure or in a microwave oven and were analysed for nutrient composition. Raw legumes served as control. The range of nutrients analysed in 100 g cooked samples were as follows: moisture, 62.8–69.7 g; protein, 14.7–24.3 g; fat, 0.9–5.9 g; ash, 1.7–4.6 g; iron, 3.3–8.6 mg; calcium, 50–209 mg; phosphorus, 249–429 mg; and thiamin, 0.14–0.32 mg. Cooking methods did not affect the nutrient composition of legumes. However, thiamine decreased in cooked samples. Cooking altered the dietary fibre content of some legumes. The mean in vitro protein digestibility of pressure-cooked and microwaved samples was 79.8% and 74.7%, respectively. The in vitro starch and protein digestibility of pressure-cooked samples were higher.

Nutrient composition and sensory profile of differently cooked green leafy vegetables

Abstract Four green leafy vegetables commonly consumed in South India were selected for the study. They were subjected to three different methods of cooking namely, conventional, pressure, and microwave cooking. Proximate composition, vitamins (ascorbic acid and β-carotene), mineral content (calcium, phosphorus, and iron), and in vitro available iron of the raw and cooked samples were estimated. The cooked samples were further subjected to sensory analysis. The results showed that the nutrient content of each green leafy vegetable was distinct and spinach was comparatively a poor source of all nutrients. Cooking caused a significant difference only in the ascorbic acid and β-carotene content of the greens. No significant difference was observed in the nutrient content due to the three different methods of cooking adopted. Results of the sensory test revealed that color was the only attribute that varied to a large extent due to cooking. Color of pressure cooked greens was considered inferior to conventionally cooked and microwave cooked samples. The sensory attributes of microwave cooked greens were similar to the conventionally cooked samples.

Effect of Ingredients on Rheological, Nutritional and Quality Characteristics of High Protein, High Fibre and Low Carbohydrate Bread

Effect of replacement of wheat flour with a combination of soy protein isolate, oat bran and chickpea flour (SPOBCP) at the levels of 20%, 40% and 60% and addition of combination of additives such as fungal α-amylase, dry gluten powder, sodium stearoyl-2-lactylate, hydroxypropylmethylcellulose (CA) on the rheological and nutritional characteristics of bread was studied. Use of SPOBCP decreased farinograph dough stability, increased pasting temperature, decreased cold paste viscosity and overall quality score of bread. Scanning electron microscopy images showed higher degree of disruption of protein matrix in bread dough with 60% SPOBCP than 20% and 40% SPOBCP. Addition of 60% SPOBCP resulted in flat, uneven shaped bread with an overall quality score of 38 when compared with 54, 81 and 91 for breads with 40%, 20% and 0% SPOBCP, respectively. However, use of CA increased the strength of the dough and improved the overall quality of bread with 40% SPOBCP. Nutritional profile of bread with 40% SPOBCP + CA showed higher protein, in vitro protein digestibility, total dietary fibre, resistant starch, β-glucan and lower starch hydrolysis index than control bread.

Nutritional Quality of Microwave and Pressure Cooked Rice (Oryza sativa) Varieties

The objective of the study was to determine the nutrient content, soluble and insoluble dietary fibre and in vitro protein and starch digestibility in four different microwave and pressure cooked rice (Oryza sativa) varieties. The rice varieties selected were Bangara Tegalu (BT, nonaromatic), Gowri sanna(nonaromatic), Jeera (mildly flavoured) and Basmati (aromatic). These were washed and cooked by microwave and pressure cooking methods and analysed for moisture, protein, thiamin, fat, total ash, iron, phosphorus, calcium, starch, dietary fibre and in vitro protein and starch digestibilities along with their raw unwashed controls by using standard techniques. The protein content of raw and cooked rice varieties ranged from 7.5 to 11.6g/100g and 7.4–11.2g/100g, respectively. There was a significant difference (p 0.05) in the protein content of two varieties of pressure and microwave cooked rice. The fat content of raw samples was 0.5–0.6g/100g. Cooking by both methods brought about a significant (p 0.01) decrease (20–60%) in the fat content of samples. Between cooking methods there was no significant difference (p 0.05). The thiamin content of raw rice varieties were between 0.16mg and 0.21mg/100g showing a significant decrease on cooking by 29–63% (pressure cooking) and 38–69% (microwave cooking). The iron content in raw samples ranged from 1.5 to 1.9mg/100g and decreased by 33–50% on cooking. The calcium (9–16mg/100g) and phosphorus (82–165mg/100g) content also showed significant decrease by cooking. The total dietary fibre in all samples was between 2.24 to 3.03g/100g, a large proportion of which was insoluble (1.97–3.00g/100g). The in vitro protein digestibility of the pressure cooked samples (82.1–91.0%) was slightly higher than the microwave cooked samples (80.0–90.8%). The starch digestibility between cooked samples were similar (92.6–93.8%) but significantly higher than raw samples. It can be concluded that cooking as such influenced the nutritional quality of rice but between the two cooking methods there were no significant differences.

Influence of amla fruits (Emblica officinalis ) on the bio- availability of iron from staple cereals and pulses

Amla fruits (Emblica officinalis) used as an acidulant in Indian dietary are claimed to be rich source of ascorbic acid, and the latter has been known to enhance intestinal absorption of dietary iron. The present study examined the beneficial influence of amla fruits, if any, on food iron availability, by virtue of their high ascorbic acid content. In this context, four cereals, four pulses, and four combinations of cereals and pulses were studied for the effect of amla fruits included at two concentrations on the in vitro iron availability. As expected, exogenous ascorbic acid added at a concentration corresponding to the amount present in the lower concentration of alma employed produced a significant enhancing effect on iron bio-availability from all the 12 food materials examined. However, supplementation of cereals and pulses with amla did not seem to have any advantage in terms of iron bio-availability. The absence of any beneficial influence of amla as evidenced here could be attributed to the significant tannin content (which was nearly half the concentration of ascorbic acid) of amla which might have countered the positive effect of native ascorbic acid. This hypothesis was supported by a supplementary study using appropriate combination of exogenous ascorbic acid and tannin.

Effect of primary processing of cereals and legumes on its nutritional quality: A comprehensive review

Abstract Cereals and legumes are important part of dietaries and contribute substantially to nutrient intake of human beings. They are significant source of energy, protein, dietary fiber, vitamins, minerals, and phytochemicals. Primary processing of cereals and legumes is an essential component of their preparation before use. For some grains, dehusking is an essential step, whereas for others, it could be milling the grain into flour. Grains are subjected to certain processing treatments to impart special characteristics and improve organoleptic properties such as expanded cereals. All these treatments result in alteration of their nutritional quality which could either be reduction in nutrients, phytochemicals and antinutrients or an improvement in digestibility or availability of nutrients. It is important to understand these changes occurring in grain nutritional quality on account of pre-processing treatments to select appropriate techniques to obtain maximum nutritional and health benefits. This review attempts to throw light on nutritional alterations occurring in grains due to pre-processing treatments.

Comparative analysis of influence of promoters and inhibitors on in vitro available iron using two methods

The investigation was undertaken with the objective of comparing two in vitro techniques, measuring dialyzable iron (method A) and measuring ionizable iron (method B), for iron bioavailability in a model system. The effect of the time of introduction of the additives on the available iron was also determined. FeSO4 solution was used as the reference source of iron, to which a series of enhancers (ascorbic acid, citric acid, maleic acid and tartaric acid) and inhibitors (tannic acid, calcium oxalate, oxalic acid, calcium carbonate and sodium phytate) were added individually at various concentrations, and available iron was estimated. From FeSO4 solution, 0.1% (method A) and 3.9% (method B) of iron was available. The addition of ascorbic acid, citric acid and tartaric acid increased this by 33–50%, 28–57% and 23–90%, respectively, for method A and by 15–89%, 24–78% and 24–93% for method B. Tannic acid, sodium phytate and calcium oxalate exhibited an inhibitory effect irrespective of the concentrations, while oxalic acid and calcium carbonate exhibited a dose-dependent inhibitory pattern. The iron availability analyzed by both methods showed a positive correlation with seven out of nine additives. An inverse relation was seen between the inhibitory effect of calcium carbonate and calcium oxalate and their time of introduction into the system. The overall observations showed that although absolute values varied widely, a positive correlation existed between the methods.

Bioaccessible nutrients and bioactive components from fortified products prepared using finger millet (Eleusine coracana)

BACKGROUND Finger millet (Eleusine coracana), a staple food in semi-arid parts of the world, is a rich source of nutrients and bioactive components comparable to rice and wheat but with higher fibre content. Unprocessed and processed finger millet (whole flour (WFM), sieved flour (SFM), wafers and vermicelli with altered matrices (added Fe or Zn or reduced fibre)) were analysed for chemical composition, bioaccessible Fe, Zn and Ca, in vitro digestible starch (IVSD) and protein (IVPD) and bioactive components (polyphenols and flavonoids). RESULTS WFM and SFM flours differed significantly in their composition. Sieving decreased the content of both nutrients and antinutrients in WFM but increased their digestibility/bioaccessibility. WFM products with Zn and Fe showed highest IVPD, whereas SFM products with Fe showed highest IVSD. Products with externally added Fe and Zn showed maximum bioaccessibility of Fe and Zn respectively. WFM had the highest levels of total polyphenols and flavonoids, 4.18 and 15.85 g kg⁻¹ respectively; however, bioaccessibility was highest in SFM vermicelli. CONCLUSION The availability of nutrients and bioactive components was influenced by both processing methods and compositional alterations of the food matrix in finger millet products, and bioaccessibility of all constituents was higher in vermicelli (wet matrix) than in wafers (dry matrix).