Microbiological and Physicochemical Quality Characteristics of Jeju Traditional Meju

This study investigated the quality characteristics of traditionally produced meju in Jeju Island.Microbial counts, proximate composition, minerals, organic acids, free sugars, isoflavones, fatty acids, and amino acids were analyzed.Total bacterial and fungal counts ranged from 9.0×10⁷ to 2.1×10 9 CFU/g and 7.0×10 5 to 1.2×10 7 CFU/g, respectively, while yeast was detected only in MJ-1.Moisture, crude protein, crude lipid, and ash contents ranged from 50.62 to 56.66%, 19.30 to 21.26%, 7.81 to 8.34%, and 2.51 to 2.81%, respectively.The pH, acid value, and salinity ranged from 5.57 to 5.61, 0.12 to 0.15 mg/g, and 0.48 to 0.80%, respectively.Amino nitrogen content ranged from 228.03 to 496.88 mg/100 g.Mineral contents followed the order K > P > Ca.Total organic acid and free sugar contents ranged from 7.01 to 17.22 mg/g and 3.08 to 16.77 mg/g, respectively.Palmitic and linoleic acids were the major fatty acids.Seventeen amino acids were detected, with total amino acid contents ranging from 20.77 to 21.11%.Isoflavone contents ranged from 399.81 to 615.12 mg/kg.These results demonstrate variation in the quality characteristics of Jeju traditional meju and highlight the need to standardize production processes and improve quality control for its use as a key raw material in traditional soybean paste production.