Protein and lysine digestibility and protein quality of cooked Filipino rice diets and milled rice in growing rats

The protein quality of typical rice-based menu of Filipino preschool child and adult and cooked milled rice was assessed for true digestibility (TD), biological value (BV) and net protein utilization (NPU) in growing rats. Lysine and energy digestibilities were also determined. For the preschool child diet, TD was 88.8%, BV 90.0%, and NPU 79.9%. For the adult diet, TD was 87.3%, BV 86.6%, and NPU 75.5%, whereas cooked rice had 90.0% TD, 82.5% BV and 74.3% NPU. Lysine digestibility was 95.4% for preschool child diet, 95.7% for adult diet, and 100.0% for rice. Digestible energy was 91.3% for preschool child diet, 93.0% for adult diet, and 95.3% in rice. Amino acid scores were 100.0% for preschooler diet, 92.1% for adult diet, and 62.2% for rice. Protein quality based on amino acid score corrected for TD was 88.8% for preschool child diet. 80.4% for adult diet, and 56.0% for rice. If based on lysine digestibility instead of TD, protein quality would be 7.1% higher.     

Effect of a Bangladeshi home-cooking procedure on the amino acid content,trypsin inhibitor activity and in vitro digestibility of some legume seeds

Raw and cooked samples of cultivars ofLens esculenta (Lentils),Pisum sativum (peas),Phaseolus vulgaris (beans),Phaseolus aureus (navy beans)Cicer arietnum (gram), andLathyrus sativus (dhal) as well as precooked commercial products were analysed for amino acids, trypsin inhibitor activity and in vitro protein digestibility. Of the fifteen samples used in the study one lentil sample, one pea sample, two gram samples and one sample of khesari dhal were from Bangladesh, one gram sample was from Sri Lanka. The other samples were obtained either in shops in Norway or from an industrial firm. The latter were also obtained precooked and dried. The two samples obtained in shops were used with hull and dehulled.Neither cooking by a Bangladeshi household procedure nor industrial precooking and drying had any effect on the amino acid contents of the samples.Cooking and precooking reduced the trypsin inhibitor activity of the raw samples more when the original activity was high then when it was low. The inhibitor activity was similar between samples after cooking.Cooking and precooking and drying increased the in vitro protein digestibility in all samples except in the lentils in which the digestibility was reduced.In the raw samples protein digestibility was negatively correlated with the trypsin inhibitor activity.     

Estimation of optimum amino acid supplements to triticale

Based on the nitrogen balance (NB) data and the efficiency of amino acid utilization, optimum supplements of limiting amino acids (AA) to triticale were calculated and their effect on true N digestibility (TD), biological value of protein (BV) and net protein utilization (NPU) of a triticale-based diet was evaluated. To determine if AA balance must be considered in the calculation of the optimum supplements, the effect of a 20% of 40% excess of essential AA in lysine-, methionine-, threonine- or tryptophan-deficient diets was also studied. The AA excess had no significant effect on NB in diets deficient in lysine, methionine or threonine. However, NB in rats fed on the tryptophan-deficient diet increased as the AA excess increased. BV of the diet containing the optimized supplements of lysine, threonine, methionine and valine was comparable to that of lactalbumin or to the diet supplemented with all essential AA. The deletion of valine from the optimized supplement caused an insignificant decrease in BV. Due to the lower TD, NPU of diets containing the optimized AA supplements was lower than that of the diet containing all essential AA or of the lactalbumin-based diet.     

Protein quality evaluation of a weaning food based on malted ragi and green gram

The nutritional quality of a malted weaning food developed using malted ragi (Eleusine coracana) and green gram (Phaseolus radiatus) was evaluated by rat feeding trials. The protein score of the weaning food was 70 calculated according to FAO/WHO (1973) pattern. The protein efficiency ratio (PER), net protein utilization (NPU), biological value (BV) and true digestibility (TD) values for the weaning food proteins at 10% level of protein intake were 2.2, 51.6, 73.8 and 82.8, respectively and the relative protein value (RPV), determined at 5, 8 and 11% levels of protein intake was 84. Supplementation of the weaning food with 10% skim milk powder enhanced the PER to 2.7 and NPU to 63.0. The nutritional quality of a roller dried proprietary weaning food was also evaluated along with malted weaning food for comparison and it was observed that the nutritional quality of the two products were comparable.     

Biological and chemical evaluation of chick pea seed proteins as affected by germination,extraction and α-amylase treatment

The effects of germination, extraction (double extraction with 70% ethanol and water at isoelectric point) and -amylase treatments of chick pea seed flours on crude protein, total carbohydrate, protein efficiency ratio (PER), biological value (BV), true digestibility (TD), net protein utilization (NPU), essential amino acid composition, in-vitro protein digestibility (IVPD) and actual amino acid indices (essential amino acid index or amino acid score) were evaluated. Crude protein content was increased (8–149%), while total carbohydrate was decreased (11–62%) by germination, extraction and -amylase treatments. Alpha-amylase treatment was more efficient in reducing total carbohydrate and increasing the protein content than that of extraction treatment. The protein quality of chick pea flours as measured by PER, BV, TD, NPU, IVPD and corrected amino acid indices (actual amino acid indices×IVPD) was significantly improved by these treatments. The protein quality of germinated--amylase treatment was comparble with casein, while germinated--amylase treaded seeds appeared nutritionally superior to casein. The results indicate that the germinated--amylase and germinated--amylase-extracted treatments could be used successfully as a source of concentrated high quality protein for baby food production. The corrected amino acid indices gave better prediction of PER, BV, TD and NPU (r=93 to 97) than actual amino acid indices (r=45 to 71). PER was highly correlated with corrected amino acid score (r=0.93). The PER could be predicted from the following simple regression equation: PER=–1.827+0.0561×corrected amino acid score.     

Pigeonpea Nutrition and Its Improvement

Abstract

Pigeonpea (Cajanus cajan [L.] Millsp.), known by several vernacular and trade names such as red gram, tuar, Angola pea, Congo pea, yellow dhal and oil dhal, is one of the major grain legume crops of the tropics and sub-tropics. It is a favorite crop of small holder dryland farmers because it can grow well under subsistence level of agriculture and provides nutritive food, fodder, and fuel wood. It also improves soil by fixing atmospheric nitrogen. India by far is the largest pigeonpea producer where it is consumed as decorticated split peas, popularly called as ‘dhal’ In other countries, its consumption as whole dry seed and green vegetable is popular. Its foliage is used as fodder and milling by-products form an excellent feed for domestic animals. Pigeonpea seeds contain about 20-22% protein and appreciable amounts of essential amino acids and minerals. Dehulling and boiling treatments of seeds get rid of the most antinutritional factors such as tannins and enzyme inhibitors. Seed storage causes considerable losses in the quality of this legume. The seed protein of pigeonpea has been successfully enhanced by breeding from 20-22% to 28-30%. Such lines also agronomically performed well and have acceptable seed size and color. The high-protein lines were found nutritionally superior to the cultivars because they would provide more quantities of utilizable protein and sulfur-containing amino acids.     

Biological evaluation for protein quality of supplementary foodsbased on popped cereals and legumes suitable for feeding rural mothers andchildren in India

Eight different formulations of supplementary foods (FS) based on poppedcereals (wheat, ragi, bajra and sorghum) and legumes (soy and bengalgram)were prepared. Four of the FS were produced with cereals, soy flour (SF)and bengalgram (BG) dhal and the other four were prepared with combinationsof cereals and SF. These blends were evaluated for food efficiency ratio(FER), protein efficiency ratio (PER) and net protein utilization (NPU)using growing albino rats. Skim milk powder (SMP, standard reference protein)was used in the control diet. In general the FER (0.28 to 0.34), PER (2.7to 2.9) and NPU (62 to 68) results of the FS were not significantly (p>0.05)different among the FS groups or compared with FER (0.36), PER (3.0) and NPU(73.5) of the control SMP. It is evident from the results that all eight FSwere nutritionally and biologically as good as SMP with regard to proximatecomposition, PER and NPU.     

Nutrient composition and protein quality of minor millets

Nutrient composition of five minor millets produced and consumed in dry land regions and tribal areas of Andhra Pradesh, India, was evaluated. The millets analysed were Italian millet (Setaria Italica), French millet (Panicum miliaceum), Barnyard millet (Echinachloa colona), Kodo millet (Paspalum scrobiculatum) and little millet (Panicum miliare). The nutrients analysed were proximate principles, amino acids, fibre components, calcium, Phosphorus and Iron. Protein and energy were evaluated by true digestability (TD), biological value (BV), net protein utilization (NPU) and digestible energy (DE) in rats. The protein content was higher and lysine content lower, when compared to major millets. Dehusked millets had lower total dietary fibre (TDF) and tannin. The TD of protein ranged between 95.0 to 99.3, whereas the BV was between 48.3 and 56.5. All the millets were poor sources of calcium, phosphorus and iron, with the exception of french millet.     

Nutritional quality of some improved cultivars of cowpea

The seeds of 13 improved cowpea cultivars were analysed for proximate composition, methionine, tryptophan and polyphenols. Considerable genetic variations were observed for the contents of protein, nonprotein nitrogen, limiting amino acids and polyphenols. The globulins contributed about 50% of the total seed proteins. A significant proportion of proteins of high protein cultivars was found to be insoluble. The proteins of most of the cultivars were found deficient in methionine and tryptophan. Methionine and tryptophan levels were negatively correlated with protein and positively correlated with carbohydrate contents. The cultivars with colored seed coats contained higher amounts of polyphenols. The difference in polyphenol content between various cultivars were due to seed coat polyphenols.     

Protein quality evaluation of sprouted maize

Protein, lysine, tryptophan, crude fibre (CF) and neutral detergent fibre (NDF) of sprouted, normal and hard endosperm opaque-2 (QPM) kernels increased, whereas in vitro protein digestibility (IVPD) decreased substantially up to five days of germination. Following the removal of radicles alone or both radicles and plumules from sprouted kernels, IVPD improved at all the stages of germination. However, the contents of lysine and tryptophan were not affected significantly. For some stages of germination, these amino acids decreased slightly. In sprouted normal kernels, IVPD was higher whereas protein, lysine and tryptophan content was lower than that of sprouted QPM kernels respectively at all the stages of germination. In four days old sprouted normal kernels, after the removal of both radicles and plumules biological value (BV), net protein utilization (NPU) and utilizable protein (UP) increased over non-sprouted kernels whereas true digestibility (TD) reach at par with non-sprouted kernels.     

Effects of germination and cooking on polyphenols and in vitro protein digestibility of horse gram and moth bean

Changes in polyphenols and in vitro protein digestibility due to germination and cooking were studied in horse gram and moth bean. Horse gram had higher amounts of polyphenols than moth bean. Polyphenol content in horse gram decreased from 1.6% to 1.1% at 48h germination, but in moth bean there was a reduction in polyphenol content from 1.3% to 1.0% at 24 h germination with a significant increase from 1.0% to 1.7% at 36 h germination. Seeds germinated for 48 h also exhibited higher amounts of polyphenols than in raw moth bean. The germination had no effect on total protein content, but a progressive increase in free amino acid content was observed in both legumes. In the ungerminated form, horse gram protein was more digestible than moth bean protein. The in vitro protein digestibility of both the legumes increased during germination. Cooking decreased the protein digestibility of horse gram either in ungerminated or germinated form, but such a decrease was noticed in moth bean at only 36 h germination. Moth bean either in raw form or germinated for 24 h did not exhibit a decrease in in vitro protein digestibility after cooking. Cooking decreased polyphenol content by 20%–50%. The apparent decrease in polyphenols in moth bean and horse gram due to cooking has been attributed to a decrease in assayable polyphenols.     

Chemical and biological characteristics of a West African weaning food supplemented with compea (Vigna unguiculata)

The effects of cowpea and amino acid supplementation on the protein quality and chemical characteristics of a maize-based West African traditional weaning food were studied. Process optimization for improved nutritive value was also determined. Supplementation of the traditional weaning food with cowpea increased the lysine, tryptophan and threonine content while the sulphur-amino acids decreased with increasing levels of cowpea. Further supplementation of 70:30 maize/cowpea blends with lysine, threonine or methionine did not significantly improve (p>0.05) protein quality in terms of the biological value (BV) and net protein utilization (NPU), although significant increases in the protein scores were noted. However, considerable improvements in the BV and NPU were recorded in blends fortified with either tryptophan alone or a combination of lysine, tryptophan, methionine and threonine. Cooking whole cowpea seeds for 45 min before incorporating in the blend formulation also significantly improved (p<0.05) the protein quality of maize/cowpea blends. The BV and NPU of blends containing 30% pre-cooked cowpea increased from 52 to 76% and 50 to 71% respectively compared to pure maize porridge. The protein content increased from 10 to 14% and the utilizable proteins more than doubled. The weight increase of experimental rats fed with these blends was comparable to that of rats on casein diet. A 30% supplementation of the maize-based weaning food with cowpea therefore greatly enhances the nutritive value especially when the cowpea is pre-cooked for 45 min. Use of chemical scores alone for such blends cannot be a reliable index of blend quality.     

Nutritive value of some wheat varieties assessed with Aspergillus flavus in comparison to rat feeding experiments

The relative nutritive value of 11 wheat varieties was assessed with the fungusAspergillus flavus. The samples were administered at 3 mg nitrogen level and the mycelial weight, obtained after 72 hours of shaking, was taken as an index of fungal biomass. The fungus graded the samples in the same order as has been done by rat. The biomass was found to be significantly and positively correlated with net protein utilization (NPU) and biological value (BV) determined by rat feeding trials.

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Zusammenfassung Der relative Nährwert von 11 Weizenarten wurde mit dem PilzAspergillus flavus abgeschätzt. Die Proben wurden mit einem Stickstoffgehalt von 3 mg angesetzt. Das Mycelgewicht nach 72 stündigem Schütteln diente als Index der Pilzbiomasse. Der Pilz sortierte die Arten in der gleichen Reihenfolge wie die Ratten. Es wurde gefunden, daß die Biomasse signifikant und positiv korreliert ist mit der netto Proteinverwertung (NPU) und dem biologischen Wert (BV), der durch Rattenfütterungsversuche erhalten wurde.

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Résumé Le valeur nutritif relatif de 11 sortes du blé a été examiné par les champignonsAspergillus flavus. Les chantillons ont été mis à l'expériment avec 3 mg du nitrogène. Le poids mycelial, obtenu après 72 heures d'agitation, a été pris comme l'index de la biomasse des champignons. Ces champignons ont gradué les échantillons au même ordre comme on l'a atteint avec les rats. Cette masse biologique a été positivement conforme à 1 utilisation de proteins propre (NPU) et à la valeur biologique (BV), déterminée par les essais d'engraissement avec les rats.

     

Effect of treatment on composition and protein and energy utilization of rice and mung bean by rats

Yellow rice derived from stack-burned unthreshed grains had lower lysine content than white milled rice. Stack burning did not affect energy digestibility in growing rats but decreased true nitrogen digestibility and net protein utilization (NPU). Increasing parboiling time from 20 to 60 min had no adverse effect on energy and protein utilization of parboiled milled rice. Defatting of rice bran-polish with petroleum ether at 50°C had no effect on protein utilization but decreased energy content and utilization. Mechanical dehulling of mung bean (Vigna radiata [L.] Wilczek) reduced fiber content, increased energy and protein digestibility but decreased biological value (BV) and NPU. Toasting and winnowing the bean reduced lysine content, improved digestible energy but decreased BV and NPU. Cooking the bean preparations improved the biological value only in mechanically dehulled bean with resultant higher NPU than that of whole bean.     

Antinutritional factors of chickpea and pigeonpea and their removal by processing

Protease inhibitors, amylase inhibitors, phytolectins, polyphenols, and oligosaccarides are important antinutritional factors of chickpea and pigeonpea. Research on these factors is reviewed and compared to those in other grain legumes. Both chickpea and pigeonpea are consumed in various forms as processed food. The effects of such processing practices as cooking, germination, and fermentation to reduce the levels of these antinutritional factors are also discussed.     

Nutritional quality of the protein in quinoa (Chenopodium quinoa,Willd) seeds

The nutritional quality of protein in quinoa seeds has been determined by amino acid assay and by animal feeding experiments. The amino acid composition of the protein in raw quinoa and washed quinoa show similar pattern. The first limiting amino acids were the aromatic amino acids thyrosine + phenylalanine giving a chemical score of 86 for protein in raw quinoa and 85 for protein in washed quinoa. Threonine was the next limiting amino acid followed by lysine. The amount of lysine and sulfur amino acids (methionine + cystine) was relatively high. In general, the content of essential amino acids in quinoa is higher than in common cereals. The animal experiments showed NPU values of 75.7, BV of 82.6 and TD value of 91.7 for the protein in raw quinoa. Results of the in-vitro enzymatic methods showed that the digestibility of the protein in quinoa is comparable to that of other high quality food proteins. The corresponding experiments carried out with samples of guinoa seeds, which have been processed to remove the saponins, showed that, the saponins do not exert any negative effect on the nutritive quality of the protein.     

Nutritional evaluation of some commercial wheat varieties grown in Pakistan

The nutritive value of some commercial wheat varieties grown in Pakistan was measured chemically, including amino acid analysis, and biologically in N-balance experiments with growing rats. The protein content ranged from 13.2% in Punjab-83 to 16% in Barani-83. Lysine per 100g protein varied between 2.46 and 2.75%. The available carbohydrate ranged from 67.3 to 74.7%. Iron content was highest in Sonalika while the concentration of zinc and manganese was highest in Sarhad-82. The protein digestibility (TD), biological value (BV) and net protein utilisation (NPU) varied between 92–95%, 56–68% and 53–65% respectively. Level of wheat protein was negatively correlated with available carbohydrate (r=–0.93), lysine per unit protein (r=–0.67) and BV (r=–0.76). The lysine content (g/16gN) of commercial wheat varieties showed a positive correlation (r=+0.95) with the BV. The protein quality was lowered in varieties having higher content of protein.     

Effect of heating and fortification with lysine on protein quality of minor millets

The effect of heating and fortification with lysine on the protein quality of five minor millets namely Italian millet (S. Italica), French millet (Panicum miliaceum), Barnyard millet (Echinochloa colona), Kodo millet (Paspalum scrobiculatum) and Little millet (Panicum miliare) was carried out. The N content of the millets ranged from 1.69 to 2.76 per cent. Proximate composition and dietary fibre was estimated. A reduction of 19–25 in TD and increase of 4–18 in BV was observed on auto-claving and both the differences were significant (P<0.05) in all millets. However, heat processing did not have a pronounced effect on DE. Fortification with lysine at 0.6 g/100 DM increased both the BV and NPU. Although both heat processing and lysine fortification improved protein utilisation, the effect of fortification was comparatively more than heating.     

The nutritive value of some selected Tanzanian plant food sources

The chemical composition of different varieties of field beans (Vicia faba L.), cowpeas (Vigna unguiculata), groundnuts (Voandzeia subterranea), and sorghum (Sorghum vulgare) were determined. Nutrients analysed in these materials included amino acids, starch, sugar, fibre, minerals and antinutritional factors. All the materials were further tested in balance trials with rats; true protein digestibility (TD), biological value (BV), net protein utilization (NPU) and digestible energy (DE) were evaluated. Based on the chemical analyses as well as on the biological data, the nutritive value of plant materials between species as well as between varieties within species differed considerably. Therefore, more quality evaluation studies along with plant breeding programmes are needed to select the most promising varieties from the nutritional point of view.     

Antinutrients in amphidiploids (black gram × mung bean): varietal differences and effect of domestic processing and cooking

Phytic acid, saponin and polyphenol contents in grains of various varieties of black gram (Vigna mungo) Mung bean (Vigna radiata L.) amphidiploids ranged from 697 to 750, 2746 to 2972 and 702 to 783 mg/100 g, respectively. Domestic processing and cooking methods including soaking, ordinary and pressure cooking of soaked and unsoaked seeds, and sprouting significantly lowered phytic acid, saponin and polyphenol contents of the amphidiploid seeds. Soaking for 18 h removed 31 to 37% of the phytic acid; the extent of removal was higher with long periods of soaking. Saponins and polyphenols were relatively less affected. Loss of the antinutrients was greater when soaked instead of unsoaked seeds were cooked. Pressure cooking had a greater effect than ordinary cooking. Antinutrient concentrations declined following sprouting; the longer the period of germination the greater was the reduction.