A Descriptive Case Study of Nuruk Manufactured from the Wheat Cultivar ‘Wooju’: Comparison with Commercial and Reference Nuruks

Nuruk, a traditional Korean fermentation starter, largely determines the quality of makgeolli; however, data on nuruk produced from novel wheat cultivars remain limited. In this descriptive case study, nuruk made from the novel wheat cultivar ‘Wooju’ (A) was characterized alongside commercial Jinju-gokja (B) and a Korea Food Research Institute reference nuruk (C), with three independently manufactured batches per type. Physicochemical, enzymatic, antioxidant, and microbiological properties were analyzed, together with qualitative Q-ToF LC-MS/MS metabolite profiles. Nuruk A showed the highest total acidity (1.19%), total polyphenol (1090 ± 15 µg GAE/g) and flavonoid (1927 ± 10 µg QE/g) contents, total fungal count, and levels of phenylalanine, tryptophan, and GABA, but the lowest α-amylase and protease activities. Of the 22 compounds detected (20 tentatively identified), six differed in detection: two lysophospholipids and a nucleotide sugar were detected only in C, two oxylipins only in A and B, and LPI(18:2) was not detected in A. Wooju-based nuruk may be suited to antioxidant-oriented applications, although its lower saccharification and proteolytic activities may require process optimization. Because the samples differed simultaneously in cultivar, starter type, and manufacturing conditions, these differences should be regarded as preliminary and cannot be attributed to the Wooju cultivar alone.