Assessment of Rat Growth Methods for Estimating Protein Quality: Interlaboratory Study

1980 ◽  
Vol 63 (3) ◽  
pp. 462-467 ◽  
Author(s):  
J Murray Mclaughlan ◽  
G Harvey Anderson ◽  
L Ross Hackler ◽  
Douglas C Hill ◽  
G Richard Jansen ◽  
...  
Keyword(s):  
Protein Efficiency Ratio ◽  
Protein Quality ◽  
Interlaboratory Study ◽  
Official Method ◽  
Efficiency Ratio ◽  
Protein Ratio ◽  
Reference Protein ◽  
Rat Growth ◽  
Growth Methods ◽  
Net Protein

Abstract An interlaboratory study involving protein efficiency ratio (PER), net protein ratio (NPR), relative NPR (RNPR) and relative nitrogen utilization (RNU) was carried out. Six collaborators assayed 6 samples, including casein plus methionine which was used as a reference protein. Collaborators prepared their own diets and analyzed the diets for nitrogen. Test proteins were added at the 8% level (N × 6.25). PER values varied more than NPR values which varied more than either RNPR or RNU. RNU and RNPR produced almost identical values, but RNPR remains the official method of choice, because it is a well established method.

Evaluation of Infant Formula Protein Quality: Comparison of In Vitro with In Vivo Methods

1988 ◽  
Vol 71 (2) ◽  
pp. 353-357
Author(s):  
David A Harris ◽  
Robert A Burns ◽  
Rida Ali
Keyword(s):  
Infant Formula ◽  
Protein Efficiency Ratio ◽  
Protein Quality ◽  
Infant Formulas ◽  
Efficiency Ratio ◽  
Protein Ratio ◽  
In Vitro Methods ◽  
Net Protein

Abstract Two-week protein efficiency ratio (2-wk PER), net protein ratio (NPR), calculated-protein efficiency ratio (C-PER), and discriminant computed- protein efficiency ratio (DC-PER) of milk- and soy-based infant formulas were compared to a 4-week protein efficiency ratio (PER). Expressed relative to ANRC casein, 2-week PER and NPR correlated significantly (P < 0.01, r = 0.90) with PER. Although C-PER and DC-PER also correlated significantly (P < 0.01) with PER, r = 0.71 and r = 0.87, respectively, these in vitro methods did not distinguish differences in protein quality among soy-based infant formulas. C-PER and DC-PER, as currently designed, are not applicable to the measurement of protein quality for all types of infant formulas.

The Relative Nitrogen Utilization Method for Evaluating Protein Quality

1976 ◽  
Vol 59 (1) ◽  
pp. 42-45 ◽  
Author(s):  
J Murray McLaughlan
Keyword(s):  
Protein Quality ◽  
Poor Quality ◽  
Nitrogen Utilization ◽  
The Other ◽  
Efficiency Ratio ◽  
Protein Ratio ◽  
Test Protein ◽  
Reference Protein ◽  
Net Protein

Abstract A single-dose rat assay for protein quality called relative nitrogen utilization (RNU) is described. The method includes a factor for the protein utilized for maintenance. The protein quality of the test protein is expressed as a per cent of the value for Iactalbumin, the reference protein. For good quality proteins RNU gives results that are similar to those obtained by net protein ratio and relative protein value; for poor quality proteins RNU results fall between values by the other 2 methods. The protein efficiency ratio (PER) gives much lower values for poor quality proteins than any of the other 3 aforementioned methods and is influenced more by both level of protein and lipid in the diet. RNU is a more precise assay than PER as judged by the coefficient of variation.

NUTRITIONAL EVALUATION OF AN ENSILED PRODUCT FROM FISH

1965 ◽  
Vol 43 (11) ◽  
pp. 1879-1883 ◽  
Author(s):  
M. A. Krishnaswamy ◽  
S. B. Kadkol ◽  
G. D. Revankar
Keyword(s):  
Protein Efficiency Ratio ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Efficiency Ratio ◽  
Protein Ratio ◽  
Protein Utilization ◽  
Streptococcus Lactis ◽  
Available Lysine ◽  
Net Protein

Ensiled fish was prepared from a local variety of freshwater fish (Barbus carnaticus) by fermentation with a pure culture of Streptococcus lactis, commercial lactose being used as a source of fermentable carbohydrate. The fermented material (pH 4.7) was roller dried. The finished product was cream colored and had a somewhat aromatic odor. It had a protein content of about 72%. Total lysine, available lysine, methionine, cystine, and tryptophan of the ensiled fish (expressed as g/16 g N) were 10.1, 8.1, 3.6, 1.1, and 1.2%, respectively. Hygienically, the product, being free from coliforms, enterococci, Salmonella, coagulase-positive staphylococci, and pathogenic anaerobes, was satisfactory. The biological value of the product as determined by protein efficiency ratio (3.3), net protein utilization (82.3%), and net protein ratio (4.2) was not significantly different from that of skim milk powder, which has a protein efficiency ratio of 3.2, net protein utilization of 82.8%, and net protein ratio of 4.9.

scholarly journals Fortifying pork liver mixture: Evaluation of protein quality and iron bioavailability – Part 2

2017 ◽  
Vol 30 (6) ◽  
pp. 817-826
Author(s):  
Silvana Mariana SREBERNICH ◽  
Gisele Mara Silva GONÇALVES ◽  
Semíramis Martins Álvares DOMENE
Keyword(s):  
Ferrous Sulfate ◽  
Protein Efficiency Ratio ◽  
Protein Quality ◽  
Iron Bioavailability ◽  
Standard Diet ◽  
Efficiency Ratio ◽  
Protein Retention ◽  
Pork Liver ◽  
Significant Difference ◽  
Net Protein

ABSTRACT Objective To evaluate the protein quality and iron bioavailability of a fortifying mixture based on pork liver. Methods Determinations of protein efficiency ratio, net protein utilization, true digestibility and hemoglobin regeneration efficiency by depletion and repletion were performed. In the depletion phase, the animals (male Wistar rats) received an iron-free AIN–93G diet and in the repletion phase they received the following diets: standard AIN–93G diet, fortifying mixture and standard diet containing heptahydrated ferrous sulfate for comparison. Results For standard AIN–93G diet and fortifying mixture the results were 3.75 and 4.04 for protein efficiency ratio and 3.53 and 3.63 for net protein retention, showing that the presence of pork liver in the diet promoted an increase in protein efficiency ratio and net protein retention (not statistically significant). True digestibility results obtained with the fortifying mixture (97.16%) were higher than those obtained with the standard AIN–93G diet (casein), but without significant difference. The hemoglobin regeneration efficiency values obtained for standard AIN–93G diet, fortifying mixture and standard diet containing heptahydrated ferrous sulfate were 50.69, 31.96 and 29.96%, respectively, showing a statistically significant difference between the control (standard AIN–93G diet) and test (fortifying mixture and standard diet containing heptahydrated ferrous sulfate) samples, but not between the test samples. Conclusion The fortifying mixture showed a high protein efficiency ratio value of 4.04 and a high relative biological value (108%) and it can be added to soups, creams and meats in day-care centers for the prevention of iron-deficiency in children of school age.

Inter- and Intra-laboratory Variability in Rat Growth Assays for Estimating Protein Quality of Foods

1984 ◽  
Vol 67 (5) ◽  
pp. 976-981 ◽  
Author(s):  
Ghulam Sarwar ◽  
Robert Blair ◽  
Mendel Friedman ◽  
Michael R Gumbmann ◽  
L Ross Hackler ◽  
...  
Keyword(s):  
Protein Quality ◽  
Protein S ◽  
Protein Ratio ◽  
Whole Wheat ◽  
Minced Beef ◽  
Test Protein ◽  
Coefficients Of Variation ◽  
Reference Protein ◽  
Rat Growth ◽  
Pea Flour

Abstract Protein efficiency ratio (PER), relative PER (RPER), net protein ratio (NPR), relative NPR (RNPR), and nitrogen utilization (NU) methods were investigated in an interlaboratory rat growth study. Six collaborating laboratories studied 7 protein sources (ANRC casein; minced beef; soya assay protein, SAP; pea flour; whole wheat flour, WW; rapeseed protein concentrate, RPC; and egg white solids, EW), and their 10 supplementary or complementary mixtures (casein + Met, SAP + Met, pea flour + Met, WW + Lys, WW + casein, WW + beef, WW + SAP, WW + pea flour, WW + RPC, WW + EW). Test protein(s) were added at the 8% level (N × 6.25). Casein + Met was used as the reference protein. Interlaboratory variation (estimated as between-laboratories coefficients of variation) of PER (up to 17.2%) was greater than that of RPER (up to 14.9%), NU (up to 9.5%), NPR (up to 7.0%), and RNPR, which had the lowest variability (up to 4.7%). In most cases, intralaboratory variation (estimated as within-Laboratories coefficients of variation) for all the methods was less than 5%.

Comparison of Interlaboratory Variation in Amino Acid Analysis and Rat Growth Assays for Evaluating Protein Quality

1985 ◽  
Vol 68 (1) ◽  
pp. 52-56 ◽  
Author(s):  
Ghulam Sarwar ◽  
Robert Blair ◽  
Mendel Friedman ◽  
Michael R Gumbmann ◽  
Ross L Hackler ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Protein Quality ◽  
Essential Amino Acids ◽  
Quality Indices ◽  
Protein Ratio ◽  
Protein Sources ◽  
Rat Growth ◽  
Positive Correlations

Abstract Estimates of inter- and intralaboratory variation of protein efficiency ratio (PER), relative PER (RPER), net protein ratio (NPR), relative NPR (RNPR), and nitrogen utilization (NU) were compared with those of amino acid analysis in the same batches of 7 protein sources (ANRC casein, egg white solids, minced beef, soy assay protein, rapeseed protein concentrate, pea flour, and whole wheat flour). Interlaboratory variation (estimated as between-laboratories coefficients of variation, CV) of NPR and RNPR (up to 6.0%) was lower than that of PER (up to 20.2%) and RPER (up to 18.5%). The interlaboratory determination of NPR and RNPR was also more reproducible than that of most essential amino acids (CV up to 10.0%), especially tryptophan (CV up to 23.7%), cystine (CV up to 17.6%), and methionine (CV up to 16.1%). Intralaboratory variation (estimated as within-laboratories CV) of amino acid analysis (up to 4.7%), however, was comparable to that of protein quality indices in most protein sources (up to 6.0%). The significant (P <0.01) positive correlations (r = 0.68-0.74) between amino acid scores and protein quality indices based on rat growth were further improved when amino acid scores were corrected for digestibility of protein (r = 0.73-0.78) or individual amino acids (r = 0.79- 0.82).

Biological protein quality and phytic acid content of domesticallyprocessed kidney beans (Phaseolus Vulgaris)

2016 ◽  
Vol 35 (4) ◽  
Author(s):  
Rajni Modgil ◽  
K. Mankotia ◽  
Ranjana Verma ◽  
Anupama Sandal
Keyword(s):  
Phaseolus Vulgaris ◽  
Phytic Acid ◽  
Phosphorus Content ◽  
Protein Quality ◽  
Protein Digestibility ◽  
Efficiency Ratio ◽  
Phytate Phosphorus ◽  
Kidney Beans ◽  
Net Protein

Effect of domestic processing techniques i.e. soaking, sprouting and cooking was seen on the anti nutrient constituents of kidney beans (Phaseolus vulgaris). Biological protein quality of sprouted and cooked grains was also estimated. Anti nutrient analyzed was phytic acid. Phytate phosphorus and non phytate phosphorus content was also estimated. Rats were fed on domestically processed kidney beans for estimation of protein efficiency ratio(PER), food efficiency ratio(FER) ,apparent protein digestibility(APD), true protein digestibility(TPD), Biological value(BV), net protein utilization(NPU) and net protein retention (NPR). Cooking of kidney beans resulted in a significant decrease in phytic acid and phytate phosphorus content as compared to sprouting. Sprouting and cooking resulted in an increase in FER and PER. Cooking resulted in an increase in biological protein quality of kidney beans. Domestically processed kidney beans have better biological protein quality.

PROTEIN QUALITY EVALUATIONS OF SELECTED CULTIVARS OF WHEAT, MEASURED BY CHEMICAL SCORES AND MOUSE BIOASSAYS

1984 ◽  
Vol 64 (1) ◽  
pp. 127-137
Author(s):  
J. M. BELL ◽  
D. M. ANDERSON
Keyword(s):  
Amino Acids ◽  
Crude Protein ◽  
Protein Quality ◽  
Growth Index ◽  
Wheat Cultivars ◽  
Protein Ratio ◽  
Relative Growth ◽  
Key Words Wheat ◽  
Limiting Amino Acid ◽  
Net Protein

Wheat cultivars, Glenlea, Inia-66, Neepawa, Pitic-62 and Twin, and Bonanza barley, were fed to mice in digestibility and protein quality evaluation trials. In the digestibility trial each diet contained 94.7% test grain, plus mineral and vitamin supplements and 0.55% chromic oxide fecal marker. Digestibility of energy ranged from 79.3% (Twin) to 83.4% (Neepawa). Digestibility of protein ranged from 71.0% (Twin) to 84.4% (Neepawa). Crude protein (CP) (N × 6.25) ranged from 11.8% (Twin) to 15.8% (Neepawa) and affected the protein apparent digestibility coefficients. In the 14-day growth trials the grains were compared in four ways: (a) as 94.7% of the diet, (b) in diets containing 9% CP, (c) in diets containing 9% CP plus amino acids to meet the requirements for growth of the mouse and (d) in diets containing 7% CP. Casein control diets were used. In (a) mice fed Twin wheat and Bonanza barley gained less than all others. In (b) all wheats resulted in slower growth than barley or casein but Twin had better protein than Inia-66 and Pitic-62, reflecting lysine contents. In (c) all wheats supplemented with amino acids equalled casein in terms of growth. In (d) the responses to 7% CP diets were inferior but parallel to those from 9% CP diets. In the protein quality evaluations barley ranked highest in relative growth index, protein efficiency ratio and net protein ratio. Twin wheat ranked second and Pitic-62 ranked last. Lysine was the first-limiting amino acid in all wheats, having from about 59 to 64% of the level required by 20- to 35-kg pigs. Isoleucine was second-limiting except for Glenlea with threonine. Key words: Wheat, cultivars, protein quality, mouse assays, digestibility

scholarly journals Nutritive value of proteins of pearl millet of high-yielding varieties and hybrids

1969 ◽  
Vol 23 (4) ◽  
pp. 913-916 ◽  
Author(s):  
A. K Goswami ◽  
K. P Sharma ◽  
K. L SEHGAL
Keyword(s):  
Pearl Millet ◽  
Dietary Protein ◽  
Nutritive Value ◽  
Protein Efficiency Ratio ◽  
Optimum Level ◽  
Lysine Content ◽  
Efficiency Ratio ◽  
Reference Protein ◽  
Limiting Amino Acid ◽  
High Yielding Varieties

1. Two high-yielding varieties and three hybrids of pearl millet were evaluated for their chemical composition and protein efficiency ratio (PER) for rats at a level of 6.38% dietary protein. PER values ranged from 0.94 to 1.21 and were significantly different.2. Tryptophan contents of the proteins were above the optimum level of the FAO reference protein. Lysine content was deficient in all the samples and was probably the limiting amino acid in the PER test.

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