There’s a new kid in town: PDCAAS, or Protein Digestibility Corrected Amino Acid Score. Well, not so new. In 1993, the Food and Drug Administration (FDA) opted to go with PDCAAS over the older Protein Efficiency Ratio (PER) to measure protein quality.
PDCAAS is based on the amino acid requirements of a 2-to-5-year-old child, considered the most nutritionally demanding group, and takes digestibility into account. PER uses an animal model. Both establish 1.00 as the top rating, which means that per unit of protein, the material provides 100% or more of indispensable amino acids. (Indispensable is a relatively new term, but it means the same thing as the older word, essential. The indispensable amino acids are not synthesized by humans and must come from the diet.)
Hitting that top mark of 1.00 are casein and whey (milk proteins), egg white and soy protein. Beef clocks in at 0.92, black beans at 0.75, peanuts at 0.52 and whole wheat at 0.42.
PDCAAS, like PER before it, comes into the picture when formulating nutritionally advanced foods, according to Terese O’Neill, key account manager, Arla Foods Ingredients, Basking Ridge, NJ. “Bakers who work with child nutrition programs are looking for ways to improve the overall nutrition of their offerings,” she said. Hence the attention paid to protein quality. “Arla’s Nutrilac whey proteins are, in this relation, good for these applications.”
Some proteins actually score higher than 1.00. Phanin Leksrisompong, PhD, technical services scientist, Davisco Foods International, Inc., Eden Prairie, MN, noted that the company’s BiPRO whey protein isolate has a value of 1.14, established by an independent laboratory specializing in conducting clinical analysis. “FDA does not allow values of greater than 1.00 to be declared on the label, so BiPRO must be written as 1.00,” she explained.