The objective of this study was to investigate the quality and environment properties of traditional Gochujang produced by 56 rural farms in 8 regions of Korea for evaluating the relationship between the components and environmental factors. Based on the regional means at the initiatory and after fermentation, the ranges of moisture content, salinity, pH, and acidity of Gochujang were determined to be from 46.87±7.09% to 43.80±7.17%, from 7.52±2.21% to 8.53±2.57%, from 5.01±0.30 to 4.63±0.34, and from 1.13±0.50% to 1.43±0.58%, respectively. The mean contents of reducing sugar and amino-type nitrogen were from 16.46±7.63% to 20.48±7.57% and from 140.06±78.00 mg% to 198.68±87.11 mg%, respectively. Hunter color values (L, a, and b) of Gochujang were from 26.16±9.27 to 22.49±9.02, from 21.87±6.31 to 20.14±7.58, and from 19.43±11.94 to 19.18±12.06, respectively. Total aerobic number was increased from 6.50±1.29 log CFU/g to 8.15±0.88 log CFU/g, while the fungal number was steadily decreased after fermentation. Next generation sequencing analysis to investigate the microbial communities revealed that

To determine sugars content of agricultural products and foods, simultaneous quantitative analysis was carried out on fructose, glucose, sucrose, maltose, and lactose by HPLC-RI. Analysis conditions were set as column ZORBAX carbohydrate (4.6 mm ID×250 mm, 5 μm), the mobile phase of 75% ACN, the column temperature of 35°C, sample injection amount of 10 μL and the flow rate of 1 mL/min. Five standard solutions were isolated without interfering peak within 30 minutes and the calibration curves of standard were confirmed excellent linearity from 0.10% to 1.00% with R2≥0.999. Based on the chromatogram of the standard solution, the limit of quantification (LOQ) and the limit of detection (LOD) values were calculated. The accuracy of the analytical values were highest at 100% water extraction method to the fructose 95.7%, sucrose 98.7%, lactose 102.7% respectively, compared with reference value of a certified reference material (BCR644), by applying the four solvent extraction methods. Using an in-house quality control material (infant formula), repeatability and reproducibility values of this experiment were verified on the basis of AOAC guideline and reference values were set up at 1.17 g/100g of glucose, 0.85 g/100g of maltose, and 45.54 g/100g of lactose. Quality control charts were drawn up and used for sugars analysis of agricultural products.

The purpose of this study was to find brewing yeast suitable for beer from the native. This study was conducted to investigate the brewing properties of beer made using different yeasts isolated from makgeolli or nuruk. Five strains (Saccharomyces cerevisiae N9, N4, YM55, YM53, and YM22) were selected based on the ability to produce alcohol in maltose-containing media. These were then fermented in wort (11 °Brix) at different temperatures (15, 20, and 25°C) for approximately 7 days and then subjected to comparative analysis. The contents of alcohol and soluble solids were within 3.2-4.6 v/v% and 6.5-7.2 °Brix, respectively. S. cerevisiae YM22 produced more alcohol (4.0%) at 15°C while N4 produced more alcohol (4.6%) at 25°C. The pH was the lowest with N4 at 25°C (pH 3.74). Glycerol content was the highest with N9 at 25°C. Among organic acids, citric acid content was the highest in all treatments. In conclusion, yeast strains isolated from makgeolli or nuruk showed potential for beer making and optimal fermentation temperature varied depending on the yeast used.

We analyzed the physicochemical properties of commercially available top-fermented beer (ale) and bottom-fermented beer (lager) marketed in Korea to compare the quality characteristics. The following characteristics of beer were analyzed for their soluble solid content, pH, total acid content, alcohol content, volatile acid content, reducing sugar content, amino acidity, and color. As results, the pH ranged from 4.01 to 4.77, 0.10-0.23 (%) for total acid and 0.25-1.47 (mL/10 mL) for amino acidity. The alcohol content was in the range of 3.10-5.70 (%) for ale and 3.80-5.20 (%) for lager. The volatile acid content was in the range of 28.67-97.93 (mg/L) for ale and 32.80-78.87 (mg/L) for lager. Regarding the color, the EBC value of the ale beers was in the 4.78-93.98 range, and that of lager beers were in the 5.48-11.98 range. Comparison of the quality characteristics of the two types of beer, revealed differences in pH, amino acidity, total acid content, reducing sugar content, and color. In particular, total acid content (t=−3.782, p⟨0.05), reducing sugar content (t=−11.744, p⟨0.05), and color (t=−2.882, p⟨0.05) of ale beer showed significantly higher than those of lager beer.

AbstractsTo increase the quality of Korean traditional yakju, we prepared seed cultures by fermentation at 20 o C for 2 days after addition of 140% water, 3% nuruk and 1.5% yeast into cooked rice. After the 200% cooked rice, 120% water and 0.08% commercial saccharifying enzyme were added to seed cultures and fermented for 2 days at 20 o C, wild ginseng was added and then further fermented for 5 days. Physicochemical properties of traditional yakju were investigated. Ethanol was produced (18.5%) by the addition of 1.2% wild ginseng. However, ethanol content was not increased by addition of microwave treated-wild ginseng and rice (either cooked rice or raw). The traditional yakju obtained by fermentation at 20 o C for 5 days, after 90 sec of microwave treated-wild ginseng was added into main fermentation broth, showed good total acceptability and also contained 791 ppm saponin.