Protein quality evaluation twenty years after the introduction of the protein digestibility corrected amino acid score method

Abstract

In 1989 the Joint FAO/WHO Expert Consultation on Protein Quality Evaluation recommended the use of the Protein Digestibility Corrected Amino Acid Score (PDCAAS) method for evaluating protein quality. In calculating PDCAAS, the limiting amino acid score (i.e., ratio of first limiting amino acid in a gram of target food to that in a reference protein or requirement) is multiplied by protein digestibility. The PDCAAS method has now been in use for 20 years. Research emerging during this time has provided useful data on various aspects of protein quality evaluation that has made a review of the current methods used in assessing protein quality necessary. This paper provides an overview of the use of the PDCAAS method as compared to other methods and addresses some of the key challenges that remain in regards to protein quality evaluation. Furthermore, specific factors influencing protein quality including the effects of processing conditions and preparation methods are presented. Protein quality evaluation methods and recommended protein intakes currently used in different countries vis-à-vis the WHO/FAO/UNU standards are further provided. As foods are frequently consumed in complement with other foods, the significance of the PDCAAS of single protein sources may not be evident, thus, protein quality of some key food groups and challenges surrounding the calculation of the amino acid score for dietary protein mixtures are further discussed. As results from new research emerge, recommendations may need to be updated or revised to maintain relevance of methods used in calculating protein quality.

An approach to including protein quality when assessing the net contribution of livestock to human food supply

“…Protein quality evaluation and methodological limitations Over the last few decades, several methods have been established for evaluating protein quality, as reviewed by Boye et al (2012). In 1989, a group of FAO and WHO expert consultants proposed the use of the PDCAAS to determine protein quality (FAO and WHO, 1991) and it has been the preferred method since then.…”

“…Values of PDCAAS > 100 where either truncated to 100% (PDCAAS t ) as suggested when the PDCAAS was introduced (FAO and WHO, 1991), or kept without truncation (PDCAAS) to include the potential of high-quality proteins to complement proteins lacking in indispensable amino acids in mixed diets (Boye et al, 2012;Rutherfurd et al, 2015). In addition to calculating PDCAAS for single inputs and outputs, PDCAAS were calculated on a barn-gate level, considering all human-edible inputs and all human-edible outputs together as an input and an output mixture, respectively, in order to account for a potentially higher protein quality of mixtures as compared with individual protein sources.…”

“…In addition to calculating PDCAAS for single inputs and outputs, PDCAAS were calculated on a barn-gate level, considering all human-edible inputs and all human-edible outputs together as an input and an output mixture, respectively, in order to account for a potentially higher protein quality of mixtures as compared with individual protein sources. The content of each amino acid in these mixtures was calculated as the sum of human-edible faecal digestible protein (kg) for each input and output times the respective amino acid content, divided by the original amount of human-edible protein present in the diet as proposed by Boye et al (2012).…”

“…Proteins are among the most important nutrients in human diets, and an adequate protein supply is a prerequisite for normal growth and development of all organs in the body (Boye et al, 2012). Adequate protein supply is defined as the ability of dietary proteins to meet the body's nutritional demands and depends not only on the amount of protein provided, but also on the protein quality in terms of the balance of (essential) amino acids and their digestibility (Neumann et al, 2002;World Health Organization (WHO) et al, 2007).…”

The quality of nourishment in the population across the regions of the Republic of Serbia from 2011 to 2013

“…Obzirom na različit hemijski sastav žita, kao i zbog različitog aminokiselinskog sastava, u ishrani bi trebalo da budu zastupljene sve vrste žitarica. 5,6 Od mlinskih proizvoda poželjno bi bilo da u ishrani preovlađuju integralna brašna od kojih bi trebalo pripremati pekarske proizvode, testenine i konditorske proizvode.…”