Protein Digestibility Assay Kit
(Animal-Safe Accurate Protein Quality Score Method)

The Protein Digestibility Assay Kit (K-PDCAAS) is used for in vitro measurement of the Animal-Safe Accurate Protein Quality Score (ASAP-Quality Score Method) developed under patent by Medallion Labs.  This digestibility score, in conjunction with the essential amino acid profile plus protein and moisture content of the sample, is used to calculate the Protein Digestibility Corrected Amino Acid Score (PDCAAS) value.

PDCAAS Product Flyer

Product Code
50 assays per kit

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International and local governmental regulatory bodies throughout the world have introduced standards by which the quality of protein in a food product may be judged for its completeness in delivery of the essential amino acids needed for human growth and sustenance.  These regulatory requirements not only assess the compositional presence of the essential amino acids but the digestibility of the proteins and relative efficiency of the release of the amino acids present.  The quality of a protein is judged from a regulatory standpoint as a function of the efficiency of protein digestion multiplied by the presence of essential amino acids.  This is in essence the foundation of the most widely accepted protein quality test, known as the Protein Digestibility Corrected Amino Acid Score (PDCAAS) test, required by most regulatory bodies when asserting a protein content claim on a commercial food product.

Traditionally, protein digestibility has been evaluated in vivo using rat subjects to measure the amount of protein digestion that occurs when fed a protein containing product.  While yielding suitable results this in vivo measurement process is costly and time consuming.

Additionally, this type of testing is prohibitive to food companies and individuals which uphold animal testing bans for compassionate reasons.

The Animal-Safe Accurate Protein Quality Score (ASAP-Quality Score) provided by this kit (K-PDCAAS), is an in vitro enzyme digestion method that has a very high correlation to the rat digestion model and uses the same casein standard as a completely digestible control.


(1) Proteins → proteins + peptides + amino acids

           (trypsin + chymotrypsin)
(2) Proteins → proteins + peptides + amino acids

                                          (pH 5.5, 70°C)
(3) Ninhydrin + α-amino acids → Ruhemann's purple + RCHO +                                                                                                        H2O + CO2

Kit size:                             50 assays
Method:                             Spectrophotometric at 570 nm
Assay time:                       ~ 6 h
Application examples:     Protein containing foods and feeds.
Method recognition:         Novel Method (Under Patent: U.S. Pat. No. 9,738,920)


  • U.S. Pat. No. 9,738,920
  • Control samples included

ASAP-Quality Score offers:
  • Animal free
  • High correlation to rat digestibility
  • Much less expensive than rat model
  • Faster turnaround time for results

AOAC Official Method 991.29 True Protein Digestibility of Foods and Food Ingredients Rat Bioassay First Action 1991.

(1995). Official methods of analysis of AOAC International. 16th Edition. Arlington, VA, AOAC International.

Protein quality evaluation.

FAO/WHO. (1991). Report of the Joint FAO/WHO Expert Consultation. Food and Nutrition Paper, No. 51.

Dietary Protein Quality evaluation in human nutrition.

FAO/WHO. (2013). Report of an FAO Expert Consultation. Food and Nutrition Paper, No. 92.

The regulation of protein content and quality in national and international food standards.

Lewis, J. L. (2012). British Journal of Nutrition, 108(S2), S212-S221.

Determination of the protein quality of cooked Canadian pulses.

Nosworthy, M. G., Neufeld, J., Frohlich, P., Young, G., Malcolmson, L. & House, J. D. (2017). Food Science & Nutrition, 5, 896-900.

In vitro method for estimating in vivo protein digestibility.

Plank, D. W. (2017). U.S. Pat. 9,738,920.

The protein digestibility-corrected amino acid score.

Schaafsma, G. (2000). The Journal of Nutrition, 130(7), 1865S-1867S.

Comparisons between true digestibility of total nitrogen and limiting amino acids in vegetable proteins fed to rats.

Sarwar, G. & Peace, R. W. (1986). The Journal of Nutrition, 116(7), 1172-1184.

United States Code of Federal Regulations.

(2017). 21CFR101.9(7), Rev. April 1.