Makjang is a short-term fermented Korean traditional paste prepared from meju powder, salt, red pepper seed powder, and red pepper powder. This study aimed to
produce low-salt barley makjang with a salt concentration of approximately 3% and to investi...
Makjang is a short-term fermented Korean traditional paste prepared from meju powder, salt, red pepper seed powder, and red pepper powder. This study aimed to
produce low-salt barley makjang with a salt concentration of approximately 3% and to investigate the effects of different meju types on microbiological and
physicochemical quality changes during fermentation.
Low-salt barley makjang was prepared using three types of meju: traditional meju powder (Makjang A), meju produced with Aspergillus oryzae (Makjang B), and meju produced with Bacillus sp. (Makjang C). Fermentation was carried out at 20 °C for 18 days, and microbiological and physicochemical characteristics were
analyzed at 3-day intervals.
Total aerobic bacterial counts in Makjang B and Makjang C were approximately 1,000 times higher than those in Makjang A. On day 18 of fermentation, total
aerobic bacterial counts were 4.68 × 10⁴ CFU/g in Makjang A, 2.97 × 10⁸ CFU/g in Makjang B, and 2.95 × 10⁸ CFU/g in Makjang C. Bacillus spp. increased until
day 12 and subsequently decreased, whereas lactic acid bacteria reached peak levels on day 9 in Makjang A (4.05 × 10⁵ CFU/g), day 12 in Makjang B (1.37 ×
10⁸ CFU/g), and day 15 in Makjang C (1.37 × 10⁷ CFU/g). Moisture content increased significantly after day 12, reaching 52.11–57.77% on day 18. The pH slightly increased to 6.21–6.52 by day 8 of fermentation, while total acidity increased significantly from 0.68–0.74% (malic acid) at day 0 to 1.46–1.62% (malic acid) at day 18. Throughout fermentation, soluble solid content ranged from 26.33 to 31.68 °Brix, and salinity was maintained at approximately 3%.
During fermentation, lightness (L*), redness (a*), and yellowness (b*) of Makjang A, B, and C gradually decreased. No significant differences in total color difference (dE*) among meju starter types were observed after 9 days of fermentation. In contrast, the color of water-soluble extracts showed increasing lightness and yellowness and decreasing redness over time. Hardness and firmness exhibited similar trends, with Makjang A showing the greatest firmness. Fermentation at 20°C resulted in visible contamination or quality deterioration at day 18; therefore, the appropriate fermentation period for low-salt barley Makjang under these
conditions is considered to be up to 15 days.
These results indicate that traditional meju, due to its diverse microbial composition, shows relatively low fermentation activity and limited suitability for standardized Makjang production. Although fermentation performance may vary depending on starter activity, the use of a single microbial strain as a starter
enables dominant microbial growth, suppresses undesirable contaminating microorganisms through microbial metabolites, and enhances functional properties.
Therefore, the use of single-strain fungal or bacterial starters is recommended for process standardization and the hygienic commercialization of Makjang.