Making a Claim: Factors Impacting Protein Quality

Originally Published: June 10, 2016
Last Updated: March 1, 2021
Animal sources score higher than plant sources when determining protein quality, because plant sources have one or more limiting amino acid.

June 10, 2016 – “Protein Digestibility Corrected Amino Acid Score (PDCAAS) is broadly used for determining protein quality; however, it has limitations,” began David W. Plank, Sr. Technical Manager, Medallion Labs, in his 2016 Protein Trends & Technologies Seminar presentation titled “Making a Claim: Factors Impacting Protein Quality and a New Way for Measuring.”

PDCAAS limitations, including required animal testing, high cost, lengthy turn-around time and large sample size requirement, have caused some to look for alternatives to this test. Medallion Labs has developed a test method called ASAP Quality Score that is comparable to PDCAAS, and it is animal-safe, less expensive and takes less time, said Plank.

If a protein claim is made, the FDA requires a food to contain at least 10% of the daily value per serving. Total grams of protein listed on package is crude protein (total nitrogen times a protein factor). But, in order to calculate the 10% DV threshold required to make a Nutrient Content Claim or Structure Function Claim; to list the protein source; or to call out the number of grams of protein on the label, the PDCAAS is required. If the PDCAAS result shows 10% DV for protein per serving of food, then the product is good to make a protein claim. Animal protein sources score high in quality, with a PDCAAS of 1. In comparison, plant sources score less than 1, due to one or more limiting amino acid(s).

To determine PDCAAS, rats are fed the sample protein in parallel with a control diet. The drawback is that the rats need to be sacrificed, which is problematic for brands that do not wish to use animal testing. However, the law requires use of this method if making protein claims.

“Not only is the pressure considerable not to use animal testing,” explained Plank, “but PDCAAS also costs approximately $5,000 per sample; takes three months for results; and can lead to an overuse of protein. Developers often over-fortify with protein in order to assure the claim is met, costing industry millions each year.”

In response, Medallion Labs has developed an animal-safe protein quality score analysis to completely emulate the PDCAAS score. Instead of using rats, the method imitates human digestion, giving good correlation to PDCAAS. Many foods have been tested with both methods and show comparable scores.

“Companies with animal-testing bans can use these results confidently,” Plank offered. Turn-around time is reduced to about 15 business days, and a much smaller sample size is required. Cost is also much lower than with traditional animal testing. The next step is to conduct an international collaborative study for AOAC Validation and for official acceptance as an alternative for animal testing, which is estimated to be a two-year process.

Meanwhile, the WHO has recommended a move to the Digestible Indispensable Amino Acid Score (DIAAS) method, which primarily uses pigs and has some advantages. “But the cost is $15-20K per sample with four to six months turn-around, and no commercial labs offer this test; private arrangements must be made with universities.” Plank said.

In summary, alternative protein sources and their quality assessment is needed. PDCAAS has drawbacks, including animal testing. ASAP Quality Score offers animal-free, good correlation to PDCAAS, is much less expensive and provides results in 15 days.

“Making a Claim: Factors Impacting Protein Quality and a New Way for Measuring,” David W. Plank, Sr. Technical Manager, Medallion Labs

The summary above is from the “2016 Protein Trends & Technologies Seminar: Formulating with Proteins Magazine.”