Unraveling the flavor formation mechanism of coconut cream through the interplay between lipid oxidation and the Maillard reaction

Abstract

This study clarifies the mechanistic coupling between lipid oxidation (LO) and the Maillard reaction (MR) in thermally processed coconut cream (CC). The oil–water–protein matrix facilitated triglyceride hydrolysis, leading to selective release of free fatty acids and reshaping the lipid precursor pool. Unlike the coconut oil system, lipid oxidation in CC proceeded under restricted conditions, where lipid-derived carbonyls were preferentially consumed through carbonyl–amine interactions rather than accumulating as secondary oxidation products. This cross-reactivity accelerated the transition from intermediate to advanced MR stages, as indicated by lower A294 but higher A420 and fluorescence intensity, and enhanced consumption of reducing sugars and glutamic acid. Integrated volatile analysis and chemometric modeling revealed that LO–MR coupling significantly intensified aroma generation, particularly α-dicarbonyl compounds such as 2,3-butanedione and 3-hydroxy-2-butanone, which contributed to the characteristic milky–caramel profile. Correlation analysis further suggested a possible association between medium-chain fatty acids and ketone formation. These findings demonstrate that flavor development in coconut cream is driven by hydrolysis-induced precursor release, restricted lipid oxidation, and efficient carbonyl flux into the Maillard reaction network, providing a theoretical basis for the food industry to design thermal processes that deliberately promote desirable milky–caramel notes while avoiding oxidative off-flavors in coconut cream and analogous plant-based emulsions.