Multidimensional quality profiling and classification of Kapi-pla: A sustainable southern Thai fermented fish paste

Kapi-pla is a traditional Southern Thai fermented fish paste produced under a zero-waste philosophy using subfresh fish, yet its quality characteristics remain scientifically underexplored. This study aimed to profile and classify the multidimensional quality of Kapi-pla by integrating physicochemical properties, freshness indicators, nutritional composition, and amino acid and fatty acid profiles. Ten samples from four regions in Southern Thailand were analyzed using conventional methods combined with Principal Component Analysis (PCA) and hierarchical clustering. Substantial variability was observed, with salt content ranging from 17.12–34.24%, pH from 6.20–6.71. Freshness indicators varied widely, with a degree of hydrolysis (DH) ranging from 7.03%–18.57%, total volatile base nitrogen (TVB) from 150.74–4,391.44 mg/100 g, and trimethylamine (TMA) up to 29.96 mg/100 g. Aged products exhibited higher levels of essential amino acids, whereas selected samples showed enrichment in ω-3 fatty acids (EPA and DHA). Multivariate analysis classified Kapi-pla into aged/high amino acid, balanced/intermediate, and fresh/fatty acid rich products. Consumer interviews indicated a preference for aged, amino acid rich products despite reduced freshness. This study provides a quantitative framework to support the quality classification, standardization, and sustainable preservation of Kapi-pla.