EVALUATION OF PROTEIN IN FOODS: III. A STUDY OF BACTERIOLOGICAL METHODS

1959 ◽  
Vol 37 (1) ◽  
pp. 1351-1360 ◽  
Author(s):  
C. G. Rogers ◽  
J. M. McLaughlan ◽  
D. G. Chapman
Keyword(s):  
Amino Acid ◽  
Protein Quality ◽  
Animal Origin ◽  
Rat Growth ◽  
Amino Acid Requirements ◽  
Growth Assay ◽  
Assay Methods ◽  
Limiting Amino Acid ◽  
Egg Powder

Bacteriological methods for the determination of protein quality were evaluated by comparison with protein efficiency ratio (P.E.R.) values determined by a standardized rat growth assay. Enzyme or acid hydrolyzates of foods were used as the source of amino acids with hydrolyzed whole egg powder as the reference standard. With Streptococcus faecalis A.T.C.C. 9790 autolysis occurred in media containing hydrolyzates of proteins deficient in lysine, and was largely responsible for results which did not agree with P.E.R. values. In methods employing Leuconostoc mesenteroides P-60 A.T.C.C. 8042, growth was influenced only by the most limiting amino acid relative to the requirements of the test organism.Results with enzyme hydrolyzates correlated poorly with P.E.R. values, whereas, with acid hydrolyzates, a good correlation was obtained for cereal proteins. A difference in amino acid requirements was largely responsible for the lack of agreement between the P.E.R. assay and methods employing L. mesenteroides, particularly for legumes and foods of animal origin. It was concluded that bacteriological assay methods which have been proposed for protein evaluation are unsatisfactory as screening procedures for the evaluation of protein in foods.

EVALUATION OF PROTEIN IN FOODS: III. A STUDY OF BACTERIOLOGICAL METHODS

1959 ◽  
Vol 37 (11) ◽  
pp. 1351-1360 ◽  
Author(s):  
C. G. Rogers ◽  
J. M. McLaughlan ◽  
D. G. Chapman
Keyword(s):  
Amino Acid ◽  
Protein Quality ◽  
Animal Origin ◽  
Rat Growth ◽  
Amino Acid Requirements ◽  
Growth Assay ◽  
Assay Methods ◽  
Limiting Amino Acid ◽  
Egg Powder

Bacteriological methods for the determination of protein quality were evaluated by comparison with protein efficiency ratio (P.E.R.) values determined by a standardized rat growth assay. Enzyme or acid hydrolyzates of foods were used as the source of amino acids with hydrolyzed whole egg powder as the reference standard. With Streptococcus faecalis A.T.C.C. 9790 autolysis occurred in media containing hydrolyzates of proteins deficient in lysine, and was largely responsible for results which did not agree with P.E.R. values. In methods employing Leuconostoc mesenteroides P-60 A.T.C.C. 8042, growth was influenced only by the most limiting amino acid relative to the requirements of the test organism.Results with enzyme hydrolyzates correlated poorly with P.E.R. values, whereas, with acid hydrolyzates, a good correlation was obtained for cereal proteins. A difference in amino acid requirements was largely responsible for the lack of agreement between the P.E.R. assay and methods employing L. mesenteroides, particularly for legumes and foods of animal origin. It was concluded that bacteriological assay methods which have been proposed for protein evaluation are unsatisfactory as screening procedures for the evaluation of protein in foods.

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 236 Determination of amino acid requirements of lysine and tryptophan of >14 wk old growing Labrador retriever puppies using the indicator amino acid oxidation technique

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 59-60
Author(s):  
Craig N Coon ◽  
Jessica L Varney ◽  
Jason W Fowler ◽  
Jordan T Weil ◽  
Mary Ann Boggess
Keyword(s):  
Amino Acid ◽  
Control Diet ◽  
Age Groups ◽  
Isotope Ratio Mass Spectrometry ◽  
Labrador Retriever ◽  
Acid Oxidation ◽  
Amino Acid Oxidation ◽  
Amino Acid Requirements ◽  
Nutrient Profiles

Abstract As the pet food industry develops products aimed to supply the nutrients necessary for the wellness and longevity of canines, it is important to understand the amino acid requirements needed for such health and growth. In this experiment, a total of six growing Labrador retriever puppies were studied during each testing period in order to determine their individual amino acid requirements through the indicator amino acid oxidation (IAAO) technique. To do this, the puppies were supplied with constant dietary Phe in the control and test diets. Excluding the control diet, a total of six diets with varying levels of the amino acid of interest were utilized in this experiment. The control diet was fed for two days, followed by a day in which the test diet was fed, a tracer amino acid was supplied, and breath samples were collected. On test day, a priming dose of L-[1-13C]phenylalanine (Cambridge Isotope Laboratories, Inc.) based on the subject’s body weight was first supplied, followed by [1-13C]Phe doses every thirty minutes, spanning a four hour period. A respiration mask was placed on each subject every thirty minutes (Oxymax, Columbus Instruments), 13CO2 was collected, and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using a broken-line model of best fit (JMP Pro 14.1). Through the segmented line regression of 13Phe oxidation, it was shown that lysine and tryptophan mean requirements were 0.627 and 0.204%, respectively. A 95% confidence interval was calculated as 0.627 ± 0.180 and 0.204 ± 0.182% (mean ± 2SD) for lysine and tryptophan, respectively, representing the population’s safe requirements. The determination of the amino acid requirements found in this study proves useful as the industry develops nutrient profiles specific to the needs of varying age groups and growing Labradors.

scholarly journals Protein content and amino acids profile in 10 cultivars of ginkgo ( Ginkgo biloba L.) nut from China

2019 ◽  
Vol 6 (3) ◽  
pp. 181571 ◽  
Author(s):  
Mengyi Zhou ◽  
Tongtong Hua ◽  
Xiaofang Ma ◽  
Haijun Sun ◽  
Li Xu
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Content ◽  
Ginkgo Biloba ◽  
Food Industry ◽  
Protein Quality ◽  
Scientific Development ◽  
Traditional Food ◽  
Limiting Amino Acid ◽  
Amino Acids Profile

As a traditional food and medicine source, ginkgo ( Ginkgo biloba L.) nut is popularly consumed in East Asia. The aim of this work is to characterize protein content and amino acids profile in 10 ginkgo nut cultivars, named successively as no. 1 to no. 10. There were observed differences among the cultivars with respect to the contents of protein and amino acids, except Cys. The no. 6 cultivar presented the highest protein content (22.1 g/100 g DW), while the no. 9 had the lowest (16.2 g/100 g DW). The contents of EAA and NEAA were revealed to vary in the range of 14.3–26.2 and 21.4–41.1 g/100 g protein, respectively. The most abundant EAA was Leu, and the first limiting amino acid was Lys. The level of Arg was attractive, especially in the no. 5 cultivar (1741 mg/100 g DW) where it is comparable to hazelnut and pistachio. As confirmed by AAS and EAAI, the no. 5 cultivar presented the best amino acids profile and protein quality among these cultivars. These results have relevance to the scientific development and application of ginkgo nuts in the food industry.

scholarly journals Macronutrient composition, true metabolizable energy and amino acid digestibility, and indispensable amino acid scoring of pulse ingredients for use in canine and feline diets

2020 ◽  
Vol 98 (6) ◽  
Author(s):  
Lauren M Reilly ◽  
Patrick C von Schaumburg ◽  
Jolene M Hoke ◽  
Gary M Davenport ◽  
Pamela L Utterback ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Dry Matter ◽  
Protein Quality ◽  
Metabolizable Energy ◽  
Macronutrient Composition ◽  
Total Dietary Fiber ◽  
Protein Sources ◽  
Indispensable Amino Acid ◽  
Limiting Amino Acid

Abstract The rising consumer demand for alternative and sustainable protein sources drives the popularity of the use of plant-based proteins in the pet food industry. Pulse crops, which include beans, peas, lentils, and chickpeas, have become an important addition to both human and animal diets due to their protein content and functional properties. However, knowledge of their nutrient composition and protein quality is necessary for the proper formulation of these ingredients in pet foods. The objective of this study was to determine the macronutrient composition and standardized amino acid digestibility and to describe the protein quality through the use of digestible indispensable amino acid scores (DIAAS-like) of five pulse ingredients. Black bean (BB) grits, garbanzo beans (GB), green lentils (GL), navy bean (NB) powder, and yellow peas (YP) were analyzed for dry matter (DM), ash and organic matter (OM), crude protein (CP), gross energy (GE), acid hydrolyzed fat (AHF), and total dietary fiber (TDF) to determine the macronutrient composition. Precision-fed rooster assays were conducted using cecectomized roosters to calculate standardized amino acid digestibility and true metabolizable energy corrected for nitrogen (TMEn). The essential amino acids, with the exception of methionine, were highly digestible with digestibility values of 80% to 90% (dry matter basis) for all selected pulse ingredients. BB grits had the lowest (P < 0.05) digestibility of arginine (86.5%) and histidine (80.6%) in contrast to GB (94.9% and 89.9%, respectively). The TMEn of GB was highest (P < 0.05) at 3.56 kcal/g compared with the other pulses. The DIAAS-like values for adult dogs were consistently the lowest for methionine for all pulses, making it the first-limiting amino acid in these ingredients. The DIAAS-like values for adult cats showed GL had lowest (P < 0.05) score in tryptophan compared with other pulses when using both AAFCO values and NRC recommended allowances as reference proteins. Methionine was the first-limiting amino acid for YP and tryptophan for GL. Based on macronutrient composition, protein quality, and amino acid digestibility, it can be concluded that pulse ingredients have the required nutritional characteristics to be viable protein sources in canine and feline foods. However, the use of complementary protein sources is recommended to counterbalance any potential limiting amino acids in pulse ingredients.

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).

NUTRIENT CONSTITUENTS OF A GRAIN APHID, METOPOLOPHIUM DIRHODUM (HOMOPTERA: APHIDIDAE), AND ITS HOST, OATS

1979 ◽  
Vol 111 (7) ◽  
pp. 787-790 ◽  
Author(s):  
M. S. Kaldy ◽  
A. M. Harper
Keyword(s):  
Amino Acid ◽  
Avena Sativa ◽  
Dry Matter ◽  
Phosphorus Content ◽  
Protein Quality ◽  
Metopolophium Dirhodum ◽  
Grain Aphid ◽  
Limiting Amino Acid ◽  
Calcium And Magnesium ◽  
Predatory Insects

AbstractMetopolophium dirhodum (Walker), a grain aphid, contained 25.58% dry matter, of which 31.65% was fat, 2.58% sugar, and 39.44% protein. Foliage of the host for M. dirhodum, oats (Avena sativa L.), contained one-third the amount of dry matter, less than one-third as much fat, slightly less sugar, and about three-fifths the amount of protein as M. dirhodum. Phosphorus content was the same in M. dirhodum and its host, whereas oat foliage contained five times as much potassium, and twice as much calcium and magnesium as M. dirhodum. The limiting amino acid in both grain aphid and oat foliage was methionine. Protein scores, which are estimates of protein quality, were slightly lower for oat foliage than for M. dirhodum but both are valuable sources of food for predatory insects and other animals.

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