Availability of Amino Acids to Microorganisms II. A Rapid Microbial Method of Determining Protein Value

Horn, Millard J.; Blum, Amos E.; Womack, Madelyn

doi:10.1093/jn/52.3.375

Cited by 22 publications

(2 citation statements)

References 2 publications

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“…Microorganisms which have been used to determine protein nutritional quality axe Streptococcus faecalis and Leuconostoc mesenteroids (12)(13)(14) and Streptococcus zymogenes (15,16). These assays were used to measure the availability of selected essential amino acids (EAA) in proteins and thereby describe protein quality based upon EAA availability.…”

Section: Assays Utilizing Microorganismsmentioning

confidence: 99%

Measuring protein quality

Satterlee

Marshall

Tennyson

1979

J Americ Oil Chem Soc

214

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An alternative to the time‐consuming and expensive PER assay for measuring food protein quality is needed by the food industry. Many biological and chemical‐based assays for measuring protein quality have been described in the literature. Most of these are still too complicated, time‐consuming, or too narrow in the range of foods they will test for daily quality control use. In the past five years, rapid methods have been developed that employ chemical assays for essential amino acid composition and availability or biological assays that measure protein digestibility and growth on food proteins. Most of these assays can be completed in five days or less and are applicable to a broad range of foods. These developments have brightened the prospects for the eventual development of a rapid assay that the food industry routinely can use to monitor protein quality. This paper has discussed two assays that were tested with a wide variety of foods and that take less than 72 hr to complete. The C‐PER assay, uses data on the in vitro protein digestibility and EAA composition of a food protein to predict its protein quality in terms of PER. The C‐PER technique is not limited by the protein, fat, additive or spice levels in the food to be tested, and is therefore applicable to a wide range of food ingredients and processed foods. The second assay is based on the growth of the protozoanTetrahymena thermophila WH14 on a proteolytic enzyme hydrolyzed food sample along with in vitro protein digestibility data to predict protein quality in terms of T‐PER. Because theTetrahymena are more difficult to control on a day to day basis, the error of the T‐PER estimate is greater than that for the C‐PER estimate. Also, sinceTetrahymena growth is greatly affected by various food additives and spices, caution should be used when this assay is used to measure protein quality in foods where the composition is not definitely known. The T‐PER assay is best suited for assaying protein quality in protein‐containing food ingredients, such as meats, flours, protein concentrates and isolates, or on foods where the exact composition is known.

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Section: Assays Utilizing Microorganismsmentioning

confidence: 99%

Measuring protein quality

Satterlee

Marshall

Tennyson

1979

J Americ Oil Chem Soc

214

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“…Only about 40% of the proteins was hydrolysed during the enzymic digestion, but the results of the tests were broadly similar to those of rat-growth tests. Horn, Blum, Womack & Gersdorff (1952) and Horn, Blum & Womack (1954) used L. mesenteroides P-60 to grade a number of differently processed cottonseed meals. The meals were incubated for successive 24 h periods with pepsin, trypsin and a preparation of pig-gut mucosa.…”

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confidence: 99%

A microbiological method for assessing the nutritional value of proteins

Ford¹

1960

Br J Nutr

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The accepted methods for measuring the nutritional value of proteins involve the use of common laboratory animals-mice, rats, chicks, dogs and others. They are laborious and costly, and much too slow for routine use for evaluating large numbers of protein samples, as in the control of the quality of animal feeding-stuffs. Several microbiological methods-some with bacteria and some with the protozoan Tetrahymena pyriformis as test organism-have been recommended for this purpose (for a review see Rosen, 1960), but none has yet been widely accepted, despite apparent advantages in simplicity and convenience. Of the bacteria, strains of Streptococcus faecalis and Leuconostoc mesenteroides have been investigated. Neither species has the ability to utilize intact protein, and hydrolysis of the test samples is a necessary preliminary to the assays. Chemical hydrolysis is not satisfactory, particularly when the purpose of the test is to evaluate foodstuffs that have been heated during processing.

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Optimisation of enzyme treatment for the degradation of feed proteins for an Escherichia coli auxotroph lysine availability assay

Erickson

Woodward

et al. 1999

J Sci Food Agric

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Availability of Amino Acids to Microorganisms II. A Rapid Microbial Method of Determining Protein Value

Cited by 22 publications

References 2 publications

Measuring protein quality

Measuring protein quality

A microbiological method for assessing the nutritional value of proteins

Optimisation of enzyme treatment for the degradation of feed proteins for an Escherichia coli auxotroph lysine availability assay

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