Comparison of the protein quality of chicken and plant-based chicken analogues using the INFOGEST in-vitro digestion system

Protein quality represents a combination of appropriate essential amino acid content and their digestibility. This study compares the proximate composition and protein quality of chicken meat (Breast and Thigh) and five commercial plant-based chicken analogue (PBCA) products using the standardised INFOGEST in-vitro gastrointestinal digestion model. Chicken exhibited significantly greater protein content (26.0-33.1 vs. 21.5-32.2 g/100 g), degree of protein hydrolysis (54-61% vs 20-33%), total amino acid digestibility (∼100% vs. 81-93%), and protein quality (digestible indispensable amino acid score (DIAAS) ≥ 100% vs. 52-65%) than PBCAs. These differences are likely attributable to plant protein structure, processing-induced aggregation, and the presence of fibre and other matrix components that restrict enzyme accessibility in plant matrices. The findings demonstrate that while plant-based chicken analogues can provide substantial protein, their digestibility and nutritional quality remain inferior to chicken, providing evidence to guide the further development of nutritionally improved plant-based meat alternatives.