Integrated Assessment of Biological, Physical, Chemical, and Sensory Qualities of “Khao Nam Phueng Muang Long” Pomelo (Citrus maxima Merr.) from Wang Chin District, Phrae Province, Thailand for Geographical Indication Authentication

Abstract

     This study assessed the integrated quality attributes of Khao Nam Phueng Muang Long pomelo (Citrus maxima Merr.) cultivated in Wang Chin district, Phrae province, Thailand, with the aim of verifying cultivar identity and evaluating its conformity with Geographical Indication (GI) standards. Thirty pomelo fruits collected from six orchards were analyzed for biological, physical, chemical, and sensory characteristics. Biological assessment focused on the origin of scion materials, while physical quality parameters included fruit weight, shape, and oil gland density. Chemical analyses comprised total soluble solids (TSS), titratable acidity (TA), pH, TSS/TA ratio, and total carotenoid content. Sensory evaluation was conducted by 30 untrained panelists using a hedonic scale. All samples originated from a single scion source, confirming their classification as the Khao Nam Phueng cultivar. The fruits exhibited superior physical characteristics relative to GI reference criteria, with mean fruit weights ranging from 1.83 to 1.97 kg and a distinctive high round shape typical of the cultivar. In contrast, chemical attributes varied among orchards. Mean TSS values ranged from 6.46 to 8.74 °Brix, which were below the GI threshold (>9 °Brix), while pH values were slightly higher than reference levels. The TSS/TA ratio showed substantial variability across samples. Sensory evaluation revealed differences in consumer acceptability, with samples SO1 and SO4 receiving the highest preference scores. Overall, Khao Nam Phueng Muang Long pomelo displayed a clear cultivar identity and distinctive physical attributes, while chemical and sensory variability highlighted the need for orchard-level management to support GI standardization.