Protein digestibility corrected amino acid score

Basic Protocol 2 Protein Digestibility-Corrected Amino Acid Score... 

PROTEIN DIGESTIBILITY-CORRECTED AMINO ACID SCORE (PDCAAS) TO DETERMINE PROTEIN QUALITY... 

Sarwar, G. 1996. The protein digestibility-corrected amino acid score method overestimates quality of proteins containing andnutritional factors and of poorly digestible proteins supplemented with limiting amino acids in rats. J. Nutr. 127 758-764. 

Henley, E. C. and Kuster, J. M. (1994). Protein quality evaluation by protein digestibility-corrected amino acid scoring. Food Technol. 48(4), 74-77. 

Recommended dietary allowance of good-quality protein is 0.83 g/kg of body weight per day with the protein digestibility-corrected amino acid score value of 1.0 (WHO, 2002). Acceptable macronutrient distribution... 

Based on the above conclusions, the consultation agreed that the protein digestibility-corrected amino acid score method was the most suitable approach for routine evaluation of protein quality for humans and recommended that it be adopted as an official method at the international level. 

The Protein Digestibility Corrected Amino Acid Score (PDCAAS) is superior to other methods for evaluating the protein quality of food proteins for humans because it measures the quality of a protein based on the amino acid requirements of a 2-5 year old child (the most demanding age group), adjusted for digestibility [120]. It has replaced the Protein Evaluation Ratio (PER). 

Sarwar, G. and McDonough, RE. Evaluation of protein digestibility-corrected amino acid score method for assessing protein quality of foods. / Assoc. Off. Anal. Chem. 73 347-356,1990. 

Schaafsma, G. Center of Expertise Nutrition, DMV International-Campina Melkunie, 6700 AA, Wageningen, the Netherlands The Protein Digestibility-Corrected Amino Acid Score. J. Nutr. 130(7) 1865S-1867S, 2000. 

Proteins have different biological availabilities in the human body and a number of methods have been introduced to evaluate and measure protein utilisation and retention. Two types of measurements are used to estimate protein quality biological assays and chemical analysis. The most common measures of protein quality included Biological Value (BV), Protein Efficiency Ratio (PER), Net Protein Utilisation (NPU), Amino Acid Score (AAS also known as chemical score, CS), Essential Amino Acid Index (EAAl) and Protein Digestibility Corrected Amino Acids Score (PDCAAS), amongst other procedures and modifications. 

House, J.D., Neufeld, J., Leson, G., 2010. Evaluating the quality of protein from hemp seed (Cannabis saliva L.) products through the use of the protein digestibility-corrected amino acid score method. J. Agri. Food Chem. 58, 11801-11807. 

Correct the amino acid score for protein digestibility by multiplying the lowest amino acid ratio with true protein digestibility (see Alternate Protocol 2). An example ... 

Since the true digestibility (the proportion of food nitrogen that is absorbed) is of crude protein is a reasonable approximation of the true digestibility of most amino acids (as determined by the rat balance method), it is recommended that amino acid scores be corrected only for the true digestibility of protein. 

A hypothetical reference protein derived from the pattern of human amino acid requirements was proposed as a standard for comparison. Shortcomings have been recognized and progress has been made in accurately evaluating human amino acid requirements. Equally critical for success is the ability to obtain precise measurements of amino acid content in the protein sources. Finally, to improve on accuracy of scoring procedures, chemically determined amino acid contents may have to be corrected for digestibility or biological availability. 

This method, proposed by Satterlee represents a modification of the chemical score technique. Amino acid analysis is used to determine the essential amino acid profile and an in-vitro proteolytic enzyme step estimates the overall digestibility of the test protein. The in-vitro protein digestibility data, together with the essential amino acid profile, are then used to predict the PER (c-PER). The results obtained so far indicate a good correspondence between the calculated PERs and the actual PERs in the rat assay. The c-PER value is thus an estimate of nutritive value, with correction of the chemical score for digestibility, but it is not a measure of amino acid availability. 

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