[Variation of amino acid components and taste correlation analysis during stir-frying process of Gardeniae Fructus]

This study investigated the dynamic changes of twelve amino acids during the processing of Gardeniae Fructus Praeparatus(Jiao Zhizi) and their association with taste properties, so as to provide a scientific basis for the underlying processing mechanism and quality assessment. Samples obtained during the stir-frying process were analyzed using an electronic tongue to quantify taste characteristics, and the contents of twelve amino acids were determined by pre-column derivatization with phenyl isothiocyanate(PITC) followed by high performance liquid chromatography(HPLC) via chemometric analysis. Correlation heatmaps were generated to explore the relationship between amino acid profiles and taste attributes. The electronic tongue results revealed an increase in bitterness(including bitter aftertaste and acidic bitterness) and astringency during the later stages of processing, while umami and richness decreased. Total amino acid content initially increased and subsequently decreased, with arginine and lysine undergoing the most substantial degradation. Chemometric analysis classified the processing into three distinct stages, identifying phenylalanine, threonine, glycine, lysine, arginine, isoleucine, and tyrosine as key amino acids indicative of the processing degree. Amino acids were significantly positively correlated with umami and richness and negatively correlated with bitterness. Arginine showed the strongest positive contribution to umami and the most significant suppressive effect on bitterness. During processing, amino acids were extensively consumed and degraded via Maillard and Strecker reaction, serving as critical precursors responsible for the enhancement of bitterness and the reduction of umami.