A validated silylation-GC-MS method for comparative analysis of distinct acid profiles in sour and conventional shrimp paste

Amino acids, fatty acids, and organic acids critically shape shrimp paste flavor, serving as taste compounds and aroma precursors. However, their simultaneous analysis remains challenging. In this study, a silylation derivatization method combined with GC-MS was established for simultaneous quantification of these compounds. The method exhibited high sensitivity, with LODs ranging from 0.26-5.02 μg/g for amino acids, 0.26-3.86 μg/g for fatty acids, and 0.92-1.96 μg/g for organic acids, along with satisfactory accuracy reflected in spike recoveries of 81.2-108.8. This method was employed to investigate the acid profiles of sour shrimp paste (SSP) and its differences from conventional shrimp paste (CSP). SSP demonstrates a markedly higher lactic acid concentration (660.75 μg/g, ten times that of CSP at 75.16 μg/g), an approximately fivefold greater content of fatty acid esters, and a unique free fatty acid profile. The established method serves as a powerful tool for the comprehensive assessment of acid profiles in shrimp paste, providing a solid methodological reference for analyzing its flavor-metabolic precursors. • A method for simultaneous quantification of acids in shrimp paste is established • High accuracy and precision are achieved with internal standard correction • Sour shrimp paste has higher lactic acid and richer fatty acid esters • Expanded GC-MS analysis scope from volatiles to acid precursors in shrimp paste