Understanding Protein Quality: PDCAAS, Bioavailability & Amino Acids

Not All Protein is Equal

Amount alone says little about the quality of a protein. Three factors are decisive: the amino acid profile, bioavailability and the scientific quality index. Anyone looking to optimise their protein intake should understand these factors.

Protein Sources Compared (per 100g)

*Rice + pea protein complement each other to form a complete amino acid profile **Limited in methionine – combination with grains recommended

PDCAAS & DIAAS – Scientific Quality Indices

PDCAAS (Protein Digestibility Corrected Amino Acid Score) and DIAAS (Digestible Indispensable Amino Acid Score) measure how well the body can utilise the protein. Higher = better.

Bunaroba combines rice and pea protein – achieving near animal-source quality.

Bioavailability – What Actually Gets Absorbed?

Bioavailability shows what percentage of protein the body can actually absorb and use (egg = 100% reference).

Essential Amino Acids – The Key

The body cannot produce 9 amino acids on its own – they must be obtained from food. For muscle building, BCAAs (leucine, isoleucine, valine) are particularly important.

Leucine is particularly important: at least 2.5g per meal should be reached to optimally stimulate muscle protein synthesis. Pea protein is one of the best plant-based sources of leucine.

Why Rice + Pea Combined?

Rice protein is rich in methionine but low in lysine. Pea protein is the opposite – rich in lysine but limited in methionine. Combined, they perfectly complement each other to form a complete amino acid profile that is comparable to animal protein.

This complementarity is not coincidental but a well-established principle of nutritional science: different plant protein sources compensate for each other’s limiting amino acids.

Conclusion

Protein quality is at least as important as quantity. Plant-based proteins can match animal sources when intelligently combined. The rice-pea combination achieves a PDCAAS of 0.96 and a bioavailability of 75–80% – nearly the values of animal reference proteins.

Learn more about optimal protein requirements by activity level and goal in our article How Much Protein You Really Need. Or calculate your individual needs directly with the Protein Calculator.

Sources:

• Rutherfurd SM et al. (2015). Protein Digestibility-Corrected Amino Acid Scores and Digestible Indispensable Amino Acid Scores. Advances in Nutrition.
• FAO (2013). Dietary protein quality evaluation in human nutrition. FAO Food and Nutrition Paper 92.
• Gorissen SH et al. (2018). Protein content and amino acid composition of commercially available plant-based protein isolates. Amino Acids.
• Joy JM et al. (2013). The effects of 8 weeks of whey or rice protein supplementation on body composition and exercise performance. Nutrition Journal.