Nutritional quality of storage proteins during germination of Indian bean (Dolichos lablab. var. lignosus) seeds

The dry Indian bean seed composed of starch is the major component (33%) and protein accounted for 25% of dry weight. The ability of germination to increase the nutritional quality of storage proteins was studied by germinating the Indian bean seeds for 0, 8, 16, 24 and 32 h and evaluated the nutritional quality through an in vitro protein digestibility (IVPD), protein efficiency ratio (PER), apparent and true digestibility. The IVPD of raw Indian bean seeds by pepsin alone was 60.12% and the digestibility by pepsin and trypsin together improved to 64.24%. The in vitro digestibility by both processes increased appreciably with germination and marked increase was noticed in the early stage of germination. The PER values followed the same pattern as the value of weight gain of rats fed with diets containing raw and germinated Indian bean. The lowest PER values were observed with raw bean diet. However, the value increased in rats fed with diets of Indian bean germinated for different intervals of time, reaching comparable PER values with the group maintained on casein diet. The true and apparent nitrogen digestibility of raw bean low being only 82 and 72%, respectively observed with casein diet. Diets with germinated bean protein showed a marked increase in both parameters, although the values were still less than that displayed by the casein fed rats. Germination is a simple biochemical enrichment tool and significantly improves palatability, digestibility and the nutritive utilisation of proteins in Indian bean seeds.     

Effect of soy protein supplementation on the nutritive value of ‘gari’ (farina) from Manihot esculenta

The supplementary role of soy protein on cassava (Manihot esculenta) “gari” or farina was studied in 35 day-old albino rats of the Wistar strain (n=6 per group) for 10 days. Gari was supplemented with soy beans at 10 and 15% soy protein levels to produce “soy gari” and the performances of rats fed the test diets compared with those on a 10% casein diet. Protein efficiency ratio (PER), Net protein utilization (NPU), true digestibility (TD) and biological values (BV) were the parameters used to assess the nutritional performance of the diets based on weight gains and nitrogen balance. The PER for 10% casein, 10 and 15% soy protein-supplemented gari groups were 2.31, 1.85 and 1.94 respectively, while the corresponding values for NPU were 71.9, 65.8 and 64.1, respectively. The TD values for the 10% casein, 10 and 15% soy protein-fed rats were 97.2, 91.9 and 90.0, respectively, while the corresponding values for BV were 73.9, 70.9 and 71.5. The PER, NPU, TD and BV for 10% casein diet were significantly superior (P<0.05) to those of the soy gari diets which gave NPU, TD and BV values 89–97% of those of the casein diet. There were no significant differences (P>0.05) in these parameters between the 10 and 15% soy protein supplementation. Soy gari is safe to the consumer, because the procedures involved in processing soy beans and cassava ensure the elimination of toxic anti-nutritional factors known to impact negatively on nutrient availability, metabolic processes and growth. It is suggested that the consumption of soy gari at 10% soy protein supplementation be promoted in gari-eating areas, to ameliorate the endemic problems of protein deficiency disorders.     

Digestibility and nitrogen retention in pigs fed diets containing dried and undried field beans treated with propionic acid

Digestibility studies with pigs weighing 40 kg were used to determine the nutritive value of diets containing dried and undried field bean (Vicia faba L) nitrogen (N) in place of soya bean N and to examine the use of propionic acid as a means of storing beans in an undried state. An addition of 2% propionic acid satisfactorily preserved moist field beans and treatment with propionic acid prior to six months' storage did not alter the nutritive value of soya bean, dried field beans or undried field beans. The digestibility of N did not differ between soya bean and undried field bean diets but the digestibility of N in the dried bean diet was lower than that in the soya bean diet. Substitution of either dried or undried field bean N for soya bean N resulted in a reduction in N retention.     

High apparent ileal digestibility of amino acids in raw and germinated faba bean (Vicia faba)‐ and chickpea (Cicer arietinum)‐based diets for rats

The effects of germinated faba bean (Vicia faba minor var Alameda)‐ and chickpea (Cicer arietinum kabuli var Athenas)‐based diets on performance, N utilisation, amino acid ileal digestibility and plasma concentrations were studied in growing male Wistar rats. Raw and germinated faba bean and chickpea seed meals were incorporated in essential amino acid‐supplemented and energy‐equalised diets as the only sources of protein. A lactalbumin‐based diet equalised in protein (100 g kg^?1) and digestible energy (15.5 kJ g^?1) with the test diets was used as control. Weight gains, gain/feed ratios, N retention and NPU values of animals fed raw or germinated legumes were lower than those of rats given the control (lactalbumin) diet, while faecal dry weights were higher. However, N retention and NPU values of rats fed germinated faba bean diets were higher and faecal dry weights lower than those of animals fed non‐germinated faba bean diets. Liver and thymus fresh and dry relative weights were lower than controls for all legume diets, whilst small intestine, caecum and colon relative weights were higher than controls for non‐germinated faba beans and chickpeas either germinated or not. Caecum and colon fresh and dry relative weights of rats fed germinated faba bean seeds were lower than those of rats fed non‐germinated faba beans and not different from controls. Except for aspartic acid and proline in rats fed raw faba bean diets, apparent ileal digestibilities of amino acids were not different or higher in rats fed legume diets as compared with controls. Except for arginine, apparent ileal amino acid digestibility was higher for germinated than for non‐germinated faba bean seeds. The amounts of glycine, arginine and ornithine in plasma significantly increased whilst those of threonine, alanine, leucine and lysine decreased with respect to controls in faba bean‐ or chickpea‐fed rats, either germinated or not. We conclude that (a) germination of faba bean seeds gave rise to a significant (P < 0.01) but limited improvement in performance, N retention and apparent ileal digestibilities of some amino acids in growing rats compared with non‐germinated seeds, while there was no detectable effect in the case of germinated chickpea seeds, and (b) the apparent ileal amino acid digestibility of essential amino acid‐supplemented diets based on faba bean or chickpea meals, either germinated or not, is similar or even higher than controls. © 2002 Society of Chemical Industry     

Effects of different levels of palm oil and sulphur in cassava-based diets

The effects of different levels of palm oil and sulphur on the nutritive value of a cassava leaf protein diet was investigated using rats. With 40% cassava and no palm oil, the protein efficiency ratio (PER) and net protein utilisation (NPU) were very low (0·3 and 23·8, respectively) but the true digestibility was the same as that of the casein control (95·0%). With 5% palm oil there was no improvement in PER but both the NPU and biological value (BV) were increased appreciably (38·1 and 40·3, respectively). The best result was obtained with 10% palm oil, with which the PER was more than doubled (0·7) and there were similar increases in both the NPU and BV (46·6 and 48·9, respectively). Cassava at the 40% level was supplemented with various sources of sulphur—i.e. methionine, sodium thiosulphate, elemental sulphur, sodium sulphate and ferrous sulphate. With methionine, the PER, compared with the control (0·7), was more than trebled (2·2) and the NPU and BV were also significantly increased (72·6 and 83·3, respectively). Elemental sulphur gave a PER of 1·8 whilst sodium sulphate and ferrous sulphate gave 1·9. The lowest PER was obtained from sodium thiosulphate (1·1). The importance of palm oil and sulphur donors in cassava-based diets is discussed.     

Protein supplementation of broad beans with sesame

Feeding experiments with weanling rats indicated that the protein of broad beans (Vicia faba var. major) and sesame (Sesamum indicum) are mutually supplementary. A standard diet in which 75% of the protein was provided by broad beans and 25% by sesame had a protein efficiency ratio (PER) of 2·36 compared to a casein PER adjusted to 2·50. A similar diet in which broad beans and sesame contributed equal amounts of protein had a PER of 2·41. The PER of broad beans was 0·99 and that of sesame 1·55.     

Influence of Tannin on Phaseolus vulgaris Protein Digestibility and Quality

The influence of tannin on protein digestibility and quality of black beans was evaluated using an enzyme-Tetrahymena thermophila bioassay. In vitro digestibility and t-PER (Tetrahymena-based PER) were inversely related to tannin content. Bioavailability, expressed by Tetrahymena growth, of black bean globulin G₁ in the presence of black bean condensed tannins correlated well (r=0.95) with the in vitro digestibility of the protein. Black bean condensed tannins complexed readily with black bean globulin G₁ to form insoluble precipitates from pH 2.0 to pH 8.0. Bean tannin-G₁ precipitates, at tannin-to G₁ ratios of 0.55 or greater, were resistant to pepsin digestion at pH 2.0. Digestion of bean tannin-G₁ precipitates was 69–74% at pH 8.0, using a multienzyme system of trypsin, chymotrypsin and peptidase.     

Some effects of fibre and starch on the determination of protein quality

An assessment was carried out of the effects of an increase in the amount of fibre, as cellulose, and of a replacement of maize starch by potato starch in diets containing egg albumen as the sole protein, on the determination of true digestibility (TD) and biological value (BV). An increase in the fibre content of the diet at the expense of maize starch led to a rise in both fascal and urinary N excretion, with diets containing either 20 or 80 g egg albumen kg^?1. However, the response of the rats to increasing fibre concentration in the diet was different for the two levels of protein probably due to differences in dry matter intake (DMI). It was found that the conventional method of estimating metabolic faecal nitrogen (MFN) was not adequate for diets of decreasing digestibility; TD decreased by 0.35% for a rise of 1% cellulose in the diet. A more accurate method of estimating MFN was derived from a relationship between the N in the faeces and the digestibility of the diet. The increase in urinary N excretion led to a decrease of 0.41% in BV for a 1% rise in the cellulose concentration of the diet. It appears, therefore, that the ratio of digestible to indigestible matter in the diet affects the determination of protein quality. The replacement of maize starch by potato starch in the diet caused an increase in faecal N excretion and a decrease in urinary N excretion until a level of 200 g potato starch kg^-1 was reached. This affected the determination of TD and BV accordingly. An increase in the size of the caecum of the rats fed potato starch indicated that increased fermentation may have resulted in production of additional bacterial cells to be excreted in the faeces. Thus, both the amount of fibre and the type of starch in the diet affect the determination of protein quality.     

The influence of dietary fibre sources on growth,feed efficiency and digestibilities of dry matter and protein in rats

Hulls from Tower canola (TCH), Regent canola (RCH) and soya beans (SBH) were included at 10 or 20% in soya bean meal based diets for rats, to compare the effects of these fibre sources on growth, feed consumption, feed efficiency and dry matter and protein digestibilities. A soya bean meal based control diet and another diet containing a purified fibre source (Alphafloc) at a 10% level, were included for a further comparison. Each of the diets was fed to six rats in a 4-week feeding trial. The diets gave similar weight gain, feed consumption and feed efficiency values. The control diet had the highest mean coefficient of dry matter digestibility (80.8%) and the 20% SBH and Alphafloc diets had the lowest (72.4 and 72.2%). The canola hull and 10% SBH and Alphafloc diets had intermediate values (73.2–75.0%). There was a highly significant negative correlation between the dietary fibre content and the dry matter digestibility of the diets. The control and Alphafloc diets showed the highest and similar apparent (81.4 and 79.9%) and true (86.8 and 85.3%) digestibility values for dietary protein. The 20% canola and soya bean hull diets showed the lowest apparent (71.4–73.7%) and true (76.9–79.4%) digestibility coefficients. The 10% canola and soya bean hull diets had intermediate apparent and true protein digestibility values (73.2-75.3 and 78.4–80.6%, respectively). The chemical analysis of the fibre sources showed that Alphafloc had the highest cellulose content (88%) and the lowest lignin content (0.6%), while canola hulls had the lowest cellulose content (25.4–28.4%) and the highest lignin content (26.6–28.9%). Soya bean hulls had intermediate cellulose (50%) and low lignin (1.3%) contents. The results suggest that cellulose did not have a detrimental effect on the dietary protein digestibility but lignin and/or some other undetermined factors in the hulls had an adverse effect on protein digestibility.     

Effects of Storage on Protein Nutritional Quality of Grain Legumes

The effect of storage under moderate conditions (12% relative humidity and 20°C) on protein nutritional quality of legumes grown in Canada (faba bean, lentil, seafarer, pinto and black beans and trapper and century peas) was determined. Little change in legume amino acid contents and only slight changes in relative net protein ratio (RNPR) and true crude protein digestibility occurred over the three years. No consistent changes were seen in plasma amino acids of rats fed the stored legumes, although plasma methionine and tryptophan were lower compared to casein-fed rats, reflecting dietary deficiencies in these amino acids. Amino acid scores indicated that tryptophan and sulfur amino acids were first and second limiting, respectively, in most of the legumes. Correction of amino acid scores for true digestibility of protein in the legumes greatly improved correlation coefficients between scores and RNPR.     

A comparison of the protein nutritive value and composition of four cultivars of faba beans (vicia faba l.) grown and harvested under controlled conditions

Faba beans (Vicia faba L.) of four cultivars, one of which was harvested in batches during the 2 months prior to normal harvesting time, and for comparison, a sample of kidney beans (Phaseolus vulgaris L.) had similar amino acid compositions with sulphur amino acids limiting in all samples. Chemical scores ranged from 45–52 and all the faba beans, when fed to rats, gave biological values in close agreement with the chemical score. Diets containing two of the cultivars were supplemented with 0.1% methionine and in both instances an increase in biological value of 22 units was obtained. Kidney beans fed to rats at the same level of crude protein resulted in the death of animals in 7–9 days. The haemaggfulinin content of the faba bean samples was 8–16 times lower than in kidney beans. Early harvesting did not affect the nutritive value of the faba beans and no differences were observed between the different cultivars, none of which showed any evidence of toxicity.     

Digestive utilisation of protein and amino acids from raw and heated lentils by growing rats

The effect of autoclave treatment on the digestive utilisation of protein and amino acids from lentils was studied in growing rats. Twenty 3‐week‐old Wistar rats (mean live weight 59 ± 4.8 g) were fed two experimental diets (n = 10 rats per diet) consisting of raw lentils (Lens culinaris M, var vulgaris, cv magda‐20) (diet RL) or lentils autoclaved at 120 °C and 1 atm for 30 min (diet AL). An additional group of 10 animals was fed a low‐protein (4%) diet and used to estimate metabolic nitrogen and amino acid excretion. Autoclaving caused a 76% reduction in the levels of trypsin inhibitor activity, but failed to improve the faecal digestive utilisation of protein or total amino acids. Lowest essential amino acid true digestibility in diets RL and AL was found for cysteine (60.2 vs 60.1%) and methionine (68.9 vs 66.6%). The protein digestibility‐corrected amino acid score was 71.2 and 66.4% and the availability of sulphur amino acid‐corrected amino acid score was 57.1 and 52.1% for diets RL and AL respectively. Sulphur amino acids were the first limiting ones. Overall, autoclave treatment did not improve protein or total amino acid digestibility from lentils, but caused a significant improvement in leucine and lysine digestibility and a significant decrease in the digestive utilisation of tyrosine and methionine. © 2002 Society of Chemical Industry     

Effect of Partial Methionine Oxidation on the Nutritional Quality of Soy Isolate and Casein

The bioavallabllity of methionine sulfoxide residues in two food proteins, casein and soy isolate, was determined in weanling (21- day-old) and mature rats (101-day-old). Methionine sulfoxide residues within these two proteins had no significant effect on protein digestibility in either group of rats or on the growth of mature rats, but slowed the growth of weanling rats. The impact of methionine sulfone on the protein efficiency ratio (PER) bioassay for protein nutritional quality, which uses weanling rats, was also measured. Results from this study indicated that for each 10% of the methionine residues which are present as partially oxidized methionlne sulfone, the PER of the protein is lowered by 0.085 units.     

Full-fat sunflower seed as a protein source for broiler chicks

The protein quality of hulled full-fat sunflower seed (HFFSS) was evaluated and compared to that of soyabean meal in two experiments with broiler chicks. In the first experiment, PER and NPR indexes were determined. The results showed that, when fed as the sole source of dietary protein (90 g crude protein kg⁻¹ diet), the performance as well as PER and NPR values of chicks fed HFFSS were much poorer than those of chicks fed soyabean meal. The protein quality of HFFSS was improved greatly by lysine supplementation. The PER and NPR values for HFFSS supplemented with 0.2 and 0.4% of L -lysine equalled and even became superior to those estimated for soyabean. In the second experiment, apparent and true ileal digestibilities of nitrogen and amino acids were calculated. The apparent but not the true digestibility of the mean of amino acids was significantly lower (P < 0.01) in HFFSS than in soyabean meal (0.838 vs 0.902 and 0.932 vs 0.957, respectively). The results also showed that lysine from HFFSS was less digestible than that from soyabean meal, the apparent as well as the true digestibility values being lower in the former. © 1999 Society of Chemical Industry     

Sensory and Nutritional Evaluation of Wheat Bread Supplemented with Single Cell Protein from Torula Yeast (Candida utilis)

Experimental breads were made with 2, 4, 6, 8, 10, and 12% torula yeast flour (TYF). Taste panels found that bread fortified with 8% TYF was acceptable. Eight percent TYF raised protein content from 12.42% for all wheat flour bread to 14.22% for supplemented bread. Amino acid analyses indicated a marked increase in amino acid content especially lysine. The protein efficiency ratio (PER) for rats on all-wheat-flour bread was 1.3 1; replacing 8% of the wheat flour with TYF raised PER of supplemented bread to 2.28. Total carcass nitrogen retained by animals fed a diet containing supplemented bread was higher than that retained by rats whose protein was obtained from unsupplemented bread.     

Hypolipidemic and hypoglycemic potential of raw,boiled, and sprouted mung beans (Vigna radiata L. Wilczek) in rats

This study was carried out to investigate the hypolipidemic and hypoglycemic potential of raw, boiled, and sprouted mung beans in rats. Oven dried mung bean powders; raw, sprouted, and boiled were included at 30% level in the diet of seven weeks old male Wistar rats maintained for 5 weeks on high (0.5%) cholesterol diet in comparison with control diet. Low serum glucose and triglyceride concentrations (p < .05) in raw and processed mung bean diets fed rats were supported by low serum insulin level in both raw mung bean diet and boiled mung bean diet fed rats. Hypoglycemic effect in sprouted mung bean fed rats was supported by higher α‐amylase inhibitory activity and α‐glucosidase inhibitory activity of sprouted mung beans. Increase in serum non‐HDL cholesterol concentration and decrease in HDL cholesterol concentration caused by high cholesterol diet were modulated (p < .05) by both boiled and sprouted mung bean diets.

Practical applications

Mung bean is a green legume rich in protein, fiber, antioxidants, and phytonutrients. Hypocholesterolemic and hypoglycemic potential of raw mung beans have been shown previously. It is well known that cooking and processing modulate nutritional and biochemical parameters of foods. However, very limited information is available on the effect of processing on functional properties of legumes. Results of this study showed that boiling and sprouting improved the soluble fiber content and hypocholesterolemic potential of mung beans. Thus, the processed mung beans may be more suitable for developing food supplements for patients with hypercholesterolemia.     

The effect of gestation and of protein quality on the nutritive utilization of protein

A study was made of the effect of protein quality on gestation and on digestive and metabolic utilization in Wistar rats. The protein level of the diet was 14%, and the protein sources used were: casein, beans and a mix of beans and wheat, in order to complement the essential amino-acids deficient in both protein sources. Gestation increased food intake in the 3 groups of experiments, in which distinct protein sources were used. Protein quality did not affect food intake in the two physiological situations under study (gestation and non-gestation). In pregnant animals, the greatest weight gains were obtained with the casein diet, while in non-pregnant ones the weight increases were greater with the diet of beans and wheat. The smallest gains recorded were those of pregnant and non-pregnant rats fed a diet of beans. Gestation did not affect protein-absorption. The digestive utilization of protein was superior with the casein diet. The study of nitrogen retention showed: 1. The pregnant animals retained more nitrogen than the non-pregnant animals with all of the diets under study. 2. In pregnant animals, the greatest metabolic utilization took place with the casein diet, with little difference between the bean and bean-wheat mix diets, although in the latter it was slightly superior.     

Effect of tannins from faba beans on protein utilisation in rats

Experimental diets with various levels (0, 8.5, 17.0 and 25.5 g kg⁻¹ diet) of a freeze-dried tannin extract obtained from faba bean seeds were evaluated in a bioassay with rats. Faecal nitrogen excretion increased and true nitrogen digestibility decreased significantly (P < 0.01) with the inclusion of tannins in the diet. In contrast, the biological value of nitrogen was apparently unaffected.     

Hypoglycemic effect and protein nutritive quality of soy and methionine-supplemented whole durum pasta products

New low cost, high-protein and high-fiber pasta products processed from whole durum meal (WD) solely. WD supplemented with 7% or 12% defatted soy flour (SF). or 12% SF plus 0.3% methionine were evaluated in comparison with the regular pasta made of pure durum semolina (DS). Their protein nutritive quality was biologically evaluated by rat growth studies using diets containing 9% protein, through the parameters: food efficiency ratio (FER), protein efficiency ratio (PER), net protein utilization (NPU), digestibility coefficient (DC) and biological value (BV). The original products were administered to diabetic hypercholesterolemic albino rats. (injected with alloxane) to study their effects on the levels of blood glucose and plasma lipid fractions. The results indicate that diets based on pasta made of WD supplemented with SE or SF plus methionine had superior protein quality and succeeded in supporting normal growth of rats in contrast to the diets based on pasta made of unsupplemented WD or DS. These assays demonstrated that the values of FER, PER. NPU and BV of WD-pasta increased with increasing SF supplementation. However, high-fiber pasta made of unrefined WD solely or with SF had lower DC values compared to that of the regular DS-pasta. DC values decreased as the added SF increased. Adding methionine evidently affected FER. PER, BV and NPU values. Administration of high-protein and high-fiber pasta samples made of WD solely, supplemented with SF or SF plus methionine significantly reduced the elevated blood glucose as well as plasma cholesterol and plasma lipid fractions in hypercholesterolemic diabetic rats. Overall, considering nutritional evaluation, protein cost as well as hypoglycemic and hypocholesterolemic effects the pasta composed of 12% SF-WD and supplemented with 0.3% methionine represented the best high-fiber: high-protein and high-quality product.     

我国3种杂豆的蛋白质营养综合评价

我国杂豆品种多、产量大,在人们的日常膳食结构中占有一定比例.现有对杂豆中蛋白质的营养评价大都是从生籽粒中提取蛋白质进行分析,膳食中的熟制处理对蛋白质的消化和氨基酸组成可能产生一定影响.文章将绿豆、红豆和豌豆整粒熟制后进行模拟口腔-胃-十二指肠消化,测定其蛋白质的胃肠消化率、可消化物中的蛋白质含量和氨基酸组成及评分.结果...