scholarly journals A new biological method for estimating food protein nutritive value

1969 ◽  
Vol 23 (3) ◽  
pp. 491-495 ◽  
Author(s):  
Shoshana Mokady ◽  
S. Vila ◽  
G. Zimmermann
Keyword(s):  
Nutritive Value ◽  
Protein Quality ◽  
Wheat Gluten ◽  
Protein Isolate ◽  
Food Protein ◽  
Protein Utilization ◽  
Nitrogen Intake ◽  
New Criterion ◽  
Net Protein

1. A new method has been devised for the nutritional evaluation of food protein quality. The method is analogous to the classical determination of net protein utilization (NPU). The suggested new criterion, the protein utilization by the liver (LPU), expresses the amount of food nitrogen ‘retained’ in the liver as a percentage of the food nitrogen intake.2. Five different foods, casein, soya-bean protein isolate, maize gluten, wheat gluten, cottonseed meal alone or with supplements of amino acids, a total of thirteen samples, were tested for LPU and NPU in groups of six rats. The correlation coefficient between values for LPU and NPU for all seventy-eight rats was +0.85 and was highly significant.

NUTRITIVE VALUE OF AIR-CLASSIFIED RAPESEED FRACTIONS

1973 ◽  
Vol 53 (1) ◽  
pp. 153-156 ◽  
Author(s):  
A. J. LESLIE ◽  
J. D. SUMMERS ◽  
J. D. JONES
Keyword(s):  
Nutritive Value ◽  
Biological Evaluation ◽  
Fat Content ◽  
Feed Consumption ◽  
Protein Utilization ◽  
Dehulled Seed ◽  
Intact Seed ◽  
Original Seed ◽  
Three Samples ◽  
Net Protein

Three samples of rapeseed, composed of high, medium, and low glucosinolate cultivars, were air-classified into various fractions and these fractions were subjected to chemical and biological evaluation. The dehulled fraction of the seed had higher protein and fat content and lower fiber content than the original seed. Digestible nitrogen (DN) and digestible energy (DE) content increased when the hull was removed. Net protein utilization was also higher in the dehulled seed than in the intact seed. No effects of glucosinolate level in the seed were noted with respect to DN or DE but feed consumption of chicks was increased on all tests when the low glucosinolate meal was fed.

scholarly journals Dietary Protein Quality in Humans—An Overview

2005 ◽  
Vol 88 (3) ◽  
pp. 874-876 ◽  
Author(s):  
Paul J Moughan
Keyword(s):  
Amino Acid ◽  
Nutritive Value ◽  
Protein Quality ◽  
Current Method ◽  
Protein Digestibility ◽  
Food Protein ◽  
Amino Acid Utilization ◽  
Dietary Amino Acid ◽  
Amino Acid Requirements ◽  
Amino Acid Score

Abstract The first objective in evaluating protein quality is to permit a ranking of proteins according to their potential nutritive value and to permit detection of changes in nutritive value due to processing and/or storage. The second objective is to permit prediction of the contribution a food protein, or mixture of food proteins, makes toward meeting nitrogen and amino acid requirements for growth or maintenance. Different approaches are used in meeting these distinct aims. The preferred current method to meet the second aim is the protein digestibility corrected amino acid score (PDCAAS). This article introduces the concept of PDCAAS and places it in the context of the series of papers published in this Special Guest Editor Section addressing aspects of dietary amino acid utilization.

scholarly journals The N:H2O ratio in the Sprague–Dawley rat and its variation with diet under the conditions of determination of net protein utilization

1967 ◽  
Vol 21 (3) ◽  
pp. 609-616 ◽  
Author(s):  
P. L. Pellett
Keyword(s):  
Dietary Protein ◽  
Age Groups ◽  
Weight Ratio ◽  
Body Water ◽  
Good Prediction ◽  
Sprague Dawley ◽  
Protein Utilization ◽  
Protein Free Diet ◽  
Net Protein

1. Analytical values are presented for body nitrogen, both on a fresh and dry carcass basis, body water and N to body water ratios for rats, of various ages, of the Sprague–Dawley Strain.2. For 33- and 40-day-old animals, there were significant differences in body composition, including N:H2O ratio, between animals given a protein-free diet and those given protein at the 10% dietary level. For all age groups the N and water percentages were higher in the carcasses of animals given the non-protein diet.3. For all age groups there were significant negative correlations between the percentage of N in the dry carcass and the net dietary protein value (NDpv) of the diet. For 33-, 37- and 40-day old animals there were significant negative correlations between the N content of the fresh carcass and the NDpv of the diet. For 33-day-old animals only, the correlation between N:H2O ratio and NDpv was also highly significant.4. Body N values calculated from N:H2O ratio and from N:body-weight ratio were compared. At all ages, an equally good prediction was obtained from the N:body-weight ration as from the N:H2O ratio provided that the correct factors were used for animals given the non-protein and test diets.

The effect of methods of sterilization on the nutritive value of protein in a commercial rat diet

1976 ◽  
Vol 35 (2) ◽  
pp. 267-276 ◽  
Author(s):  
D. J. Ford
Keyword(s):  
Amino Acids ◽  
Nutritive Value ◽  
Protein Quality ◽  
Point Of View ◽  
Chemical Methods ◽  
True Digestibility ◽  
Complete Protein ◽  
Net Protein ◽  
Total Amino Acids

1. The effect on protein quality of treating a commercial rat diet by autoclaving at various temperatures for different periods of time, or by irradiation with 2.5 or 10 Mrd, was studied. True digestibility (TD) and biological value (BV) were measured and the available and total amino acids in the diets were estimated using microbiological and chemical methods..2. Autoclaving at 121° for 60 min reduced BV, TD and net protein utilization (NPU) more than autoclaving at 134° for 3 min. Availability of amino acids was reduced by both treatments but to a greater extent by autoclaving at 121° for 60 min. Total amino acids were essentially unaffected. Irradiation had no effect on BV, TD, NPU or total amino acids, and the availability of amino acids was also unaffected, with the exception of lysine which was slightly reduced..3. When the diet was autoclaved at 115 or 121° for 15, 30 or 60 min, or at 134° for 3 min the availability of the amino acids was reduced with increasing time and temperature of treatment. Treatment at 134° for 3 min had an effect on available amino acids similar to treatment at 121° for 15 or 30 min..4. Ethylene oxide fumigation of the diet caused reduced availability of histidine, methionine and tryptophan but had negligible effect on arginine, leucine and lysine..5. It is concluded that from a practical point of view irradiation causes least damage to proteins in rodent diets. If such diets are to be autoclaved they should be supplemented with complete protein to counteract amino acid destruction.

EVALUATION OF PROTEIN IN FOODS: 1. A METHOD FOR THE DETERMINATION OF PROTEIN EFFICIENCY RATIOS

1959 ◽  
Vol 37 (1) ◽  
pp. 679-686 ◽  
Author(s):  
D. G. Chapman ◽  
Raul Castillo ◽  
J. A. Campbell
Keyword(s):  
Protein Quality ◽  
Corn Starch ◽  
Sole Source ◽  
Male Rats ◽  
Protein Retention ◽  
Wistar Strain ◽  
Bioassay Procedure ◽  
Net Protein

A bioassay procedure for the evaluation of the nutritional quality of the protein in foods is described. This method involves measurement of the protein efficiency ratio (grams gain per gram protein consumed) under standardized conditions. Male rats of the Wistar strain 20–23 days of age are fed ad libitum an otherwise adequate reference diet containing 10% protein supplied by a standard sample of casein. Foods to be assayed are added to the diet as the sole source of protein at the expense of the casein and corn starch to maintain a protein level of 10%. Protein efficiency ratios (P.E.R.'s) are calculated after 4 weeks and are adjusted to a constant value of 2.5 for casein. Although influenced by the age of rat and subject to certain inherent criticisms, determination of P.E.R. values was found to be a simpler method for evaluating protein quality than determination of net protein retention or net protein utilization and equally sensitive.

EVALUATION OF PROTEIN IN FOODS: 1. A METHOD FOR THE DETERMINATION OF PROTEIN EFFICIENCY RATIOS

1959 ◽  
Vol 37 (5) ◽  
pp. 679-686 ◽  
Author(s):  
D. G. Chapman ◽  
Raul Castillo ◽  
J. A. Campbell
Keyword(s):  
Protein Quality ◽  
Corn Starch ◽  
Sole Source ◽  
Male Rats ◽  
Protein Retention ◽  
Wistar Strain ◽  
Bioassay Procedure ◽  
Net Protein

A bioassay procedure for the evaluation of the nutritional quality of the protein in foods is described. This method involves measurement of the protein efficiency ratio (grams gain per gram protein consumed) under standardized conditions. Male rats of the Wistar strain 20–23 days of age are fed ad libitum an otherwise adequate reference diet containing 10% protein supplied by a standard sample of casein. Foods to be assayed are added to the diet as the sole source of protein at the expense of the casein and corn starch to maintain a protein level of 10%. Protein efficiency ratios (P.E.R.'s) are calculated after 4 weeks and are adjusted to a constant value of 2.5 for casein. Although influenced by the age of rat and subject to certain inherent criticisms, determination of P.E.R. values was found to be a simpler method for evaluating protein quality than determination of net protein retention or net protein utilization and equally sensitive.

scholarly journals Studies on the composition of food

1966 ◽  
Vol 20 (4) ◽  
pp. 747-755 ◽  
Author(s):  
N. Chamberlain ◽  
T. H Collins ◽  
G. A. H Elton ◽  
Dorothy F Hollingsworth ◽  
D. B Lisle ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Nicotinic Acid ◽  
High Speed ◽  
Protein Quality ◽  
Dehydroascorbic Acid ◽  
Pilot Scale ◽  
Mechanical Agitation ◽  
Protein Utilization ◽  
Net Protein ◽  
Made In

1. The Chorleywood Bread Process is a new method of making bread in which the 2–4 h of bulk fermentation of the dough normal in breadmaking is replaced by a few minutes of intense mechanical agitation to a controlled degree in special high-speed mixers. It is now being used to make over 30% of British bread. 2. Bread was made in a commercial bakery from two white flours by the Chorleywood Bread Process and a conventional method. 3. Both the bread and flours were analysed for moisture, protein, ash, fat, carbohydrate (by difference), thiamine, nicotinic acid and ascorbic acid. 4. More bread was made by the two processes from two other flours in a pilot-scale bakery. These breads and flours were used to determine net protein utilization values. 5. It was concluded that bread made by the Chorleywood Process cannot be distinguished from conventional bread in its content of protein, fat, ash and nicotinic acid, and in protein quality as indicated by its net protein utilization value. This was true for two grades of flour. In these tests the contents of thiamine and moisture were slightly higher and of carbohydrate slightly lower in Chorleywood than in conventional bread. No ascorbic or dehydroascorbic acid could be detected in any of the bread.

scholarly journals Note on the determination of net protein utilization by carcass analysis

1957 ◽  
Vol 11 (2) ◽  
pp. 138-139 ◽  
Author(s):  
A. E. Bender ◽  
B. H. Doell
Keyword(s):  
Protein Utilization ◽  
Net Protein
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