Physicochemical and sensory properties of Kefir supplemented with lactic acid bacteria derived from Makgeolli and commercial strains

This study evaluated the effects of Makgeolli -derived lactic acid bacteria (ML) as an adjunct culture on the quality characteristics of kefir. Kefir prepared using kefir grains supplemented with ML (M) was compared with kefir supplemented with Lactococcus lactis subsp. lactis (LL) or Lactobacillus delbrueckii subsp. bulgaricus (LB) and kefir prepared using a commercial starter culture (Com). The M, LL, and LB samples exhibited significantly lower pH values and higher viscosities than Com (p < 0.05). Their lightness values ranged from 81.74 to 81.92, compared with 71.69 for Com, while their fat contents ranged from 3.59 to 4.08%, compared with 0.85% for Com (p < 0.05). Total bacterial and LAB counts were significantly higher in M, LL, and LB than in Com, with M exhibiting the highest LAB count (p < 0.05). Electronic-nose analysis clearly differentiated the treatments, with PC1 and PC2 explaining 94.763 and 3.667% of the total variance, respectively, while M was characterized by stronger buttery, creamy, cheesy, and fruity aroma profiles. Electronic-tongue analysis also distinguished the treatments, with PC1 and PC2 accounting for 98.059 and 1.086% of the total variance, respectively. M received the highest scores for texture (9.00), taste (8.80), and overall acceptability (8.89) on a 10-point scale (p < 0.05). These findings indicate that ML may serve as an effective adjunct culture for improving the microbial and sensory quality of kefir.