Novel enzyme-induced colour transition in plant-based meat analogues using natural pigments

Colour is a critical quality attribute in plant-based meat analogues (PBMAs), serving as an immediate indicator of freshness, biochemical integrity, and consumer perception. This study investigated the optimization of natural pigments in combination with laccase enzyme to imitate authentic beef colour transition in PBMAs. The optimized anthocyanin and carotenoid pigments with laccase (LC Opt ) achieved the target CIE Lab coordinates in both uncooked and cooked states, compared with the commonly used methylcellulose (MC Opt ) in the industry. The LC Opt samples had significantly higher browning index and browning polymer content than beef, attributed to polyphenol-mediated oxidation and carbohydrate-driven reactions. The pigment migration pattern showed preferential association of anthocyanins with pea protein isolates, while carotenoids localized to textured vegetable proteins in the colour-optimized samples. The total anthocyanin, total phenolic, and total antioxidant content were higher in MC Opt than LC Opt , due to the formation of oxygen-limited gel matrix that stabilizes pigments in patties. The free amino acid pool was higher in beef; arginine was the exception, occurring at approximately tenfold higher levels than in PBMAs. Across beef and PBMAs, lysine correlated positively with the browning index, whereas methionine and phenylalanine correlated negatively. Pigment combinations appear more effective than single-pigment screening, reflecting the complex pigment-protein interactions in the matrix. Overall, an optimized pigment combination with a laccase enzyme is a potential approach to achieve enhanced, beef-like colour transitions in next-generation meat analogues.