Deciphering the flavor constituents, microbiota and physicochemical properties of Yancaigao, a traditional sour rice paste from Southwest China.

Yancaigao, a distinctive fermented condiment indigenous to Southwest China, imparts unique sour flavor profile to various culinary applications. This study investigated the organic acid profile, volatile flavor constitutes, and microbial community of two fermented and six blended Yancaigao samples. Organic acid analysis revealed that lactic acid (86.51-117.28 mg/g) was the predominant organic acid in fermented Yancaigao, accounting for 97.40-98.08 % of total organic acids. It was significantly higher than those observed in blended Yancaigao (1.92-13.91 mg/kg). Headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) analysis identified 88 volatile compounds, mainly encompassing acids (10), alcohols (23), aldehydes (19), ketones (13), esters (5), pyrazines (4), ethers (2), olefins (2), benzene (1), and sulfide (1). Lactic acid, 2,3-butanediol, dimethyl trisulfide, 1-octen-3-one, and dimethyl disulfide were determined to be key aroma compounds of the eight Yancaigao samples, based on odor activity value and Orthogonal partial least squares-discriminant analysis (OPLS-DA). Notably, trans-α,α-5-trimethyl-5-vinyltetrahydro-2-furanmethanol and 2,3-pentanedione were exclusively detected in fermented Yancaigao. Microbial community analysis revealed that Pseudomonas (43.37 %) and Methyloversatilis (14.03 %) were the dominant microorganisms, indicating potential microbial contamination. This study could provide valuable insights for quality evaluation and integrated development of traditional fermented Yancaigao.