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1.
As a part of a cooperative study initiated to assess bothin vitro andin vivo protein quality methods, the protein efficiency ratio (PER) and net protein ratios (NPR) of 15 different protein sources were determined. Male weanling Sprague-Dawley rats were fed a 10% protein diet. Fourteen-day NPR and relative NPR (RNPR) values and 14- and 28-day PER and relative PER (RPER) values were calculated for each protein source. When protein quality values were expressed relative to ANRC casein, the 14- and 28-day PER data ranked the protein sources essentially in the same order. RPER values of nonfat dried skim milk (unheated) and tuna were more than 100% that of casein; nonfat dried skim milk (heated), chickpeas, and breakfast sausage were between 50 and 70% of that of casein; and pinto beans and rice-wheat gluten cereal did not support substantial growth of the rat. The NPR method did not always rank the protein sources in the same order as the PER method. For the poor quality proteins, RNPR values were much higher than the RPER values; however, the RNPR and RPER values agreed closely for high quality protein sources.A preliminary report of this work was given at the Annual Meeting of the Federation of American Societies for Experimental Biology, Washington, D.C., March 29–April 2, 1987. Fed. Proc. 1987; 46: 889.  相似文献   

2.
Values (%) for true digestibility of crude protein and individual amino acids in 20 selected foods were determined by the rat balance (fecal) method. The products were fed as the sole source of protein in diets containing 8% crude protein (N × 6.25). Lowest true protein digestibility values (79–84) were obtained for pinto beans, kidney beans and lentils; intermediate values (89–92) were obtained for chick peas, beef stew, skim milk (over heated), rolled oats, whole wheat cereal, and pea protein concentrate; and highest values (94–100) were obtained for sausage, macaroni-cheese, rice-wheat gluten cereal, skim milk, tuna, soy isolate, peanut butter, chicken frankfurters, beef salami, casein and casein + methionine. In animal foods, peanut butter and soy isolate, the differences between true digestibility of crude protein and most individual amino acids were less than 5%. However, the values for true digestibility of methionine and cystine were up to 44% lower than those of crude protein in pinto beans, kidney beans, lentils, chick peas and pea concentrate. In these legumes, digestibility of crude protein was not a good predictor of digestibility of the limiting amino acids.  相似文献   

3.
The powder forms of soy-based infant formulas obtained from four manufacturers were fed to weanling rats for two weeks, as the sole source of protein in diets containing 8% protein, 20% fat, and adequate amounts of minerals and vitamins. The relative protein efficiency ratio (RPER) and the relative net protein ratio (RNPR) values (casein + methionine=100) of diets containing unsupplemented formulas were 71–81 and 78–85, respectively. Supplementation of the formula diets with lysine (0.2%), methionine (0.2%), threonine (0.1%) or tryptophan (0.05%) increased the level of the supplemental amino acid in rat serum but generally failed to improve the RPER or RNPR values. Addition of all four essential amino acids to the formula diets, however, caused a marked improvement in their protein quality (RPER or RNPR values=100). The data suggested that proteins in soy-based formulas could be marginally co-limiting in several indispensable amino acids.Presented in part at the 202nd annual meeting of the American Chemical Society, New York City, 25–30 August 1991.  相似文献   

4.
Germination and fermentation were investigated as methods of improving the nutritional and organoleptic properties ofsoybean and African breadfruit seed based food formulations.Four products consisting of germinated-fermented soy-breadfruitseeds (GFSB), nongerminated-fermented soy-bread-fruit seeds(NGFSB), germinated-nonfermented soy-breadfruit seeds (GNFSB)and nongerminated-nonfermented soy-breadfruit seeds (NGNFSB)were prepared. Phytic acid contents, in vitro protein digestibilities, protein efficiency ratios (PER), net proteinratios (NPR), flavor, appearance and overall acceptabilitywere evaluated. Germination followed by natural lactic fermentation significantly (p < 0.05) reduced the phytic acid by a factor of 11.6 in NGNFSB compared to reductionfactors of 2.1 and 1.5 in GNFSB and NGFSB, respectively.The in vitro protein digestibility (%), PER and NPR valuesof 73.4, 2.46 and 3.62 for GFSB; 71.1, 2.35 and 3.46 for NGFSB;68.7, 2.16 and 3.41 for GNFSB were significantly (p < 0.05)higher than the 64.7, 1.82 and 2.11 for NGNFSB. The meansensory scores were 5.26–5.67 for GNFSB, 4.66–4.94 forNGNFSB, 4.33–4.80 for GFSB and 4.27–4.34 for NGFSB on a7-point rating scale.  相似文献   

5.
The chemical compositions, of raw and treated lupine flour were determined and compared with other plant protein sources. The protein content in the dry matter was 47.7% in untreated seeds ofLupinus mutabilis and about 56% in debittered seeds. The oil-cake contained 65.3% protein. The amino acid analysis showed that lupine protein is characterized by a low level of S-amino acids, the content of which amounts to only 50% of that of the FAO standard reference pattern. The protein quality was measured using the biological tests PER (Protein Efficiency Ratio), NPU (net protein utilization), and BV (biological value) in rats on diets with and without DL-methionine supplementation. PER determinations gave low values for the non-supplemented lupine proteins (1.34, semi-sweet variety; 1.53, water-extracted seeds; 1.19, oil-cake; 3.09, casein), but the PER's were improved by the addition of 0.2% DL-methionine to the diets (3.05, 2.69, 2.81, respectively). Raw as well as processed lupine protein showed an excellent apparent digestibility (80.0–85.8%; casein, 87.1%). The observed NPU and BV values confirmed the importance of methionine supplementation. The true digestibility of 92% was equivalent to that of casein. The complementation effects of mixing lupine protein with proteins from wheat, oat, barley, rice, maize, potato, quinua or fish were investigated by determination of the PER values of the respective mixtures. Feeding lupine protein with cereal proteins resulted in PER values that exceeded by far those of the proteins fed separately (true complementation). This result was not observed for the mixture of potato and lupine. High quality proteins like quinua and fish protein also showed no complementation effect with lupine protein but did improve the quality of the lupine protein to a great extent. The best results could be obtained with combinations of three different plant proteins, in which lupine protein always contributed one third of total protein. These mixtures resulted in PER values equal to those for casein or other animal proteins and may be applied as an economical way to prevent and combat malnutrition.  相似文献   

6.
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.  相似文献   

7.
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.  相似文献   

8.
The ability of seed germination to increase the nutritional quality of chickpea was studied. Chickpea flours germinated for 0, 24 and 48 h were evaluated nutritionally by determination of protein efficiency ratio (PER), net protein ratio (NPR), digestibility and essential amino acid availability in vivo. A significant increase in ascorbic acid was observed during germination. PER and NPR values indicated that germinated chickpea flours compared favorably to casein. Protein digestibility decreased as germination time increased. Essential amino acid availability did not change after 24 h of germination, but a small decrease was observed after 48 h. The increase in some amino acids during germination may account for the observed increase in PER for the germinated flours. Seed germination enhanced significantly the nutritional quality of chickpea protein and substantially increased the ascorbic acid level.Contribution No. 4359, Arizona Agricultural Experiment Station, University of Arizona, Tucson, AZ 85721, USA.  相似文献   

9.
Rapeseed protein concentrate (RPC), rapeseed 2S and 12S fractions, a blend of 2S and 12S fractions, retentate (RET) and precipitate (PRE) proteins obtained during rapeseed fractionation were compared to casein for nutritive value as determined by net protein ratio (NPR) and apparent digestibility coefficient (ADC). Tyrosine concentration in rapeseed 2S fraction was the lowest compared to all other protein sources and methionine was the first limiting amino acid. The NPR and ADC of RPC, RET, and fraction 12S did not change significantly (P<0.05) following supplementation with methionine, but for PRE the NPR was decreased significantly (P<0.05). However, the rapeseed 2S fraction supplemented with tyrosine had a NPR significantly (P<0.05) higher than that of RPC and not significant (P<0.05) different from that of casein. The NPR of the 2S and 12S blend was significantly (P<0.05) higher than that of RET and PRE; however, no significant (P<0.05) difference was observed in NPR and ADC of the blend when supplemented with tyrosine. The nutritive value and digestibility of rapeseed 2S fraction were improved by supplementation with tyrosine and by blending with the 12S fraction.  相似文献   

10.
Amino acid supplementation studies with young rats were carried out using raw and processed amaranth grain (A. cruentus) of dark- and cream- or light-colored seeds. The results of various studies repeatedly indicated that threonine is the most limiting amino acid in raw and processed, dark and cream-colored grain. Protein quality as measured either as NPR or PER was improved by threonine addition alone or with other amino acids and decreased liver fat to values similar to those measured with casein. This finding contradicts the reports that state that leucine, determined by chemical score, is the most limiting amino acid. Leucine addition alone or with other amino acids did not improve protein quality. The study confirmed cream-colored grain to be nutritionally superior to dark grain and that properly processed grain, light- or dark-colored, has higher protein quality than raw grain.INCAP Publication I-1525  相似文献   

11.
Two varieties of mesta (Hibiscus sabdariffa) seeds were analysed for their proximate composition. Their protein (18.8–22.3%), fat (19.1–22.8%) and dietary fiber (39.5–42.6%) contents were found to be high. The seeds were found to be a good source of minerals like phosphorus, magnesium and calcium. Their lysine and tryptophan contents were also high. Sulphur containing amino acids were limiting in this seed protein and the chemical score of mesta seed protein was 40 and 57 for AMV-2 and Bhimili-1 varieties respectively. Mesta seed oil is rich in unsaturated fatty acids (70%), of which linoleic acid constituted 44%. Weanling rats were fed with 10% mesta seed protein before and after cooking for 4 weeks. Food intake of animals receiving raw mesta seed diets was significantly lower than those receiving cooked mesta seed diets as well as the casein control diet. Protein and dry matter digestibilities of raw and cooked mesta seed diets were lower than that of casein control diet. Cooking improved the food intake, gain in body weight, dry matter and protein digestibility of mesta seed diets. PER and NPU of cooked mesta seed diets were significantly higher than the corresponding raw diets. These results indicate that cooked mesta seed protein is of relatively good quality.  相似文献   

12.
The protein quality of Nigerian traditional diets based on the African yambean (AYB) and pigeon pea (PP) were performed by in vivo and in vitro bioassays. The individual foods were processed, cooked, dried and mixed to resemble the traditional diets. Weanling male Wistar rats (45–55 g) were used for the bioassay. The rats were fed ad libitum for 35 days of which 28 days were for growth and 7 days for N-balance. All the eleven diets including casein (control) provided 1.6 g N/100 g diet. The parameters tested include PER, growth, N-balance, BV, NPU and apparent digestibility (AD). The rats fed the AYB diets, except AYB: Agidi (Ag), showed superiority in most of the parameters tested. There were significant positive correlations between PER and NPU (r=0.925;p<0.001); PER and AD (r=0.908;p<0.001); PER and body weight gain (r=0.969;p<0.001). The in vitro protein digestibility of the diets was significantly correlated (r=0.80;p<0.01) with the in vivo apparent digestibility. These parameters were used to rank the various diets. Crayfish protein was a better supplement to legume/cereal or legume starchy staple mixtures than leguminous oil seed. However, supplementation of PP: steamed corn (SC) diet with crayfish did not prove beneficial. The result showed that diets based on the African yambean, an under-exploited legume, are nutritious. The need for its reintroduction into the fare of the populace through increased production and appropriate processing technology is stressed. The results of this study can form a base for the standardization of Nigerian diets based on these legumes.  相似文献   

13.
Samples of 15 food products and feces obtained by feeding them to rats were analysed for dietary fiber fractions. The food products were added as the sole source of protein in 8% protein diets, making up 8.8–51.6% of the diets. Diets were supplemented with 0.54–5.00% purified cellulose to make them more comparable in total fiber. Fiber analyses of food products revealed that the protein sources provided 0.06–7.27% total dietary fiber. The true protein digestibility in rats was negatively correlated with the total food fiber level (r=–0.69,P<0.01) or with the food cellulose level (r=–0.82,P<0.01) but it was positively correlated (r=+0.81,P<0.01) with the purified cellulose level. No relationship was found between protein digestibility and fiber fermentability. Results indicate that several food fiber fractions and possibly associated substances influenced protein digestibility. Purified cellulose did not have the same physiological behavior as food cellulose from the viewpoint of protein digestibility and fiber fermentability.  相似文献   

14.
Amino acid composition, protein digestibility, calculated protein efficiency ratio (C-PER and DC-PER), chemical scores and water-soluble vitamin content of cowpea seeds germinated at 25°C or 30°C for 24h were determined. Also, the effect of processing steps (heated-air drying, decortication and cooking) on these parameters were examined. Germination had little effect on amino acid profile of cowpeas. In vitro protein digestibility was not improved significantly by germination nor by decortication but was improved by cooking. C-PER and DC-PER ranged from 1.95 to 2.21 and from 1.63 to 1.82, respectively. DC-PER compared well withreported rat PER of cowpea products and seemed more sensitive than C-PER. Based on whole egg values, chemical scores ranged from 37.7 to 45.8% (mean±SD; 42.2±2.4%). Germination increased the contents of niacin, thiamin and riboflavin significantly. Decortication resulted in up to 30% loss in niacin while thiamin content was reduced 41% by cooking.  相似文献   

15.
A 2-wk feeding study with weanling rats was conducted to investigate theeffects of tryptophan supplementation of soy-based infant formulas on proteinquality and on the levels of blood and brain tryptophan and brain serotoninand 5-HIAA (5-hydroxyindole-3-acetic acid), a metabolite of serotonin. Thepowder and liquid concentrate forms of soy-based infant formulas obtainedfrom four manufacturers were tested. The tryptophan contents of the testsoy-based formulas (10.0–12.3 mg/g protein) were considerably lower comparedto those of human milk (17–19 mg/g protein). The infant formulas were fedas the sole source of protein in diets containing 8% protein, 20% fat, 5%cellulose and adequate amounts of minerals and vitamins. In general, supplementation of the diets containing test formulas with graded levels ofL-tryptophan (0.1 or 0.2%) had no effect on protein quality indices basedon rat growth such as PER (protein efficiency ratio), NPR (net protein ratio)and relative NPR (RNPR), but resulted in significant (p<;0.05) increases inthe concentrations of tryptophan in the plasma and brain, and serotonin and5-HIAA in brain of rats. The increased concentrations of brain tryptophan and5-hydroxyindoles (serotonin + 5-HIAA) in rats fed tryptophan-supplementedformulas compared to those fed unsupplemented formulas support the need forfurther research to investigate the influence of tryptophan supplementationof soy-based infant formulas on tryptophan metabolites and their potentialrelated effects on sleep latency and neurobehavioral developments in infants.  相似文献   

16.
Four oat cultivars adapted for soil and climate conditions in the southern region of Brazil were evaluated for protein nutritive value. Evaluations were done both in vitro and in vivo. In vitro evaluation was done by essential amino acid profile, available lysine, amino acid scoring, and protein digestibility corrected amino acid-scoring (PDCAAS). Nitrogen balance indices and PER were determined in vivo with rats. In all four cultivars (UFP-15, UFP-16, CTC-03, UFRGS-14), lysine was the most limiting amino acid. Available lysine, amino acid score and PDCAAS were highest for cultivar UFRGS-14 and lowest for CTC-03. When compared to casein, only nitrogen retention for UFRGS-14 did not differ statistically (p>0.05); all other indices of protein quality were inferior to casein for the oat cultivars. The oat cultivars tended to be identical among themselves, except for apparent protein digestibility which was significantly higher in the UFRGS-14 and CTC-03 cultivars. On average, the PER values of the oat cultivars were 82% of casein; the net protein utilization was 88% of casein as determined in vivo and 49% by the estimation in vitro (PDCAAS).  相似文献   

17.
Lysine bioavailabilities in reference protein and 16 test protein diets were estimated using 10 day rat growth assays. A standard growth curve was obtained by feeding 5 diets containing casein, zein and synthetic amino acids ranging in total lysine concentration from 0.3 to 0.7%. Experimental foods were added to the basal diet at the expense of zein and/or synthetic amino acids to provide 2 specific lysine concentrations, i.e., 0.4 and 0.6%. Availabilities were established by comparing growth responses from the test food diets to the regression line of the standard growth data. Availabilities were over 88% for 13 of 16 products. Utilization was poor in pinto beans (73%), rice-wheat gluten cereal (70%), and skim milk powder heated to 100°C for 12 h (66%). Addition of excess lysine (700 mg/100 g diet) to the pinto bean diet did not improve growth response; thus poor digestibility or some unidentified growth inhibitor is indicated.  相似文献   

18.
The phytic acid content of four different varieties of beans under different processing conditions was estimated. It was highest in red kidney (1.86–2.13%) slightly lower in pigeon (1.86–2.03%), white (1.80–1.96%) and black eyed beans (1.15–1.64%). There was no significant change in phytic acid content of beans after soaking at 25°C for 22 hours. However, both soaking and cooking revealed 26–37% loss of phytic acid in all four varieties of beans.The rate of in vitro casein digestibility with and without phytic acid at concentrations found in legumes was determined at pH 8 and 37°C using multienzyme technique. Addition of 5 mg Na-phytate reduced the casein digestibility up to 20% compared to the control. However, only 25% reduction of casein digestibility was observed in the presence of 25 mg of Na-phytate. Higher concentration of Na-phytate had no significant effect on the rate of casein digestibility. Data strongly suggest the formation of protein phytate complex at alkaline pH of small intestine.Part of this work was presented at the XIII International Congress of Nutrition in Brighton, UK in August 1985.  相似文献   

19.
This study was conducted to evaluate the protein quality of four types ofedible mushrooms common in Jordan in terms of protein digestibility –corrected amino acid score (PDCAAS), which is a combination of thechemical score of the limiting amino acid multiplied by true digestibility ofthe protein. True protein digestibility values were low (61.4, 73.4, 52.6and 80.5 for Terfezia claveryi, Pleurotus ostreatus, Tricholoma terrum and Agaricus macrosporus, respectively). Based onthe essential amino acids pattern requirements for children, the limitingamino acids in P. ostreatus and A. macrosporus protein weresulphur-containing amino acids with chemical scores of 0.61 and 0.50,respectively. However, lysine was the limiting amino acid in the protein ofT. claveryi and T. terreum with chemical scores of 0.71 and 0.67,respectively, and the PDCAAS was 0.43, 0.45, 0.35 and 0.40 for themushrooms types, respectively. Considering the pattern of essential amino acid requirements of laboratory rats, thesulphur containing amino acids were the limiting amino acids in the proteinof T. claveryi, P. ostreatus, T. terreum and A.macrosporus with chemical scores of 0.56, 0.30, 0.34 and 0.25,respectively. The PDCAAS were 0.34, 0.22, 0.17 and 0.20,respectively. It is concluded that the four mushroom types studied are of lowprotein quality.  相似文献   

20.
Tryptophan bioavailabilities were estimated in 16 protein sources using 10 day rat growth assays with casein as the reference protein. Growth responses of rats fed test food diets were compared to growth responses of rats fed basal diets with graded levels of tryptophan ranging from 50 to 100 mg of tryptophan/100 g diet. Estimates of tryptophan availabilities were 85–100% for all products except whole wheat cereal (73%) and pinto beans (59%). Results of a previous study on lysine availability indicated that poor response to pinto beans was due either to poor digestibility or to the presence of some unidentified growth inhibitor.  相似文献   

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