The aim of the present study was to investigate the quality characteristics of the aronia cultivar ‘Viking’ as affected by cultivation region. Aronia cultivated in 5 different regions (Danyang, Geochang, Gangjin, Gochang, and Ganghwa) was collected. pH, total acid, soluble solid, redness, total anthocyanin, total polyphenol, tannin, and organic acids were analyzed. Correlation analysis was also performed to determine the relationship between the quality characteristics of aronia and meteorological factors in each cultivation region. All variable assessed differed significantly among samples. pH ranged between 3.86-4.06. The highest pH was recorded in aronia cultivated in Gochang. Aronia grown in Ganghwa had the highest total acid, soluble solid, and total anthocyanin content and the highest redness. Malic acid, tartaric acid, and citric acid were detected in all aronia samples, with malic acid being the predominant organic acid in the aronia cultivars. Correlation analysis revealed pH and soluble solid content to have significant positive correlations with sunshine duration. However, redness showed a significant negative correlation with precipitation. Therefore, it can be confirmed that cultivation region play an important role in determining the quality characteristics of aronia ‘Viking’ from the results of this study.

Nuruk is a traditional Korean fermentation starter containing various microbes; it is utilized for the synthesis of alcoholic beverage. In this study, the changes in the quality characteristics and microbial community during the cultivation period of nuruk were analyzed. The results indicated that the fungal richness, expressed as Chao 1, from 70.0 to 19.3 on day 10 and subsequently increased to 35.0 on day 30 of cultivation. The content ratio of Aspergillus sp., Rhizopus sp. and Saccharomycopsis sp. increased with the progress of cultivation. Among the fungi, the content of the Aspergillus genus increased from 0.01% before cultivation to 70.4 %. Among the bacteria, the content of the Pantoea genus increased to 69.76% on day 7 and decreased to 44.80% on day 14. Considering the enzyme activity, saccharogenic power, α-amylase and carboxy peptidase exhibited the highest activity on day 7 while lipase exhibited the highest activity on day 14. Considering only the enzyme activity, the results indicated that it would be appropriate to terminate cultivation before day 14. The traditional cultivation period of nuruk is approximately 14 days; However, it is necessary to determine a suitable cultivation period for the application of nuruk as enzyme source.

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.

This study aimed to control sugar consumption during makgeolli fermnetation using high temperature treatments after 3 days of fermentation at normal temprature. makgeolli fermentation was performed at 25°C for the initial 3 days and at 34, 37, 40, and 43°C, respectively, for the next 4 days. When fermented at 25°C (control), the alcohol content increased up to 16.5%; however the alcohol content of makgeolli treated at elevated temperatures reduced by 13.8 %. In the control group, typical saccharification and fermentation proceeded simultaneously, and the reducing sugar content remained low due to sugar consumption by active yeast. However, at high fermentation temperatures, the nuruk enzymes functioned normally and saccharification proceeded well; however the conversion of fermentable sugars to alcohol was inhibited, possibly due to a decrease in yeasts activity. The viable cell count of yeasts was 4-6 log CFU/mL regardless of the fermentation temperature. These results indicate the possibility of producing sweet live-yeast makgeolli without the addition of artificial sweeteners through a temperature-controlled makgeolli fermentation.

This study was conducted to investigate the characteristics of Yakju fermented using different 7 commercial yeasts; La parisienne (black), La parisienne (red), Fermivin, RC212, K1-V1116, D47, and EC1118. After completion of fermentation, the total acid content in Yakju ranged from 0.26 to 0.40%; the lowest and highest values corresponded to fermentation using La parisienne (red) and EC1118, respectively. The amino acidity of the different Yakju samples varied significantly in the range of 2.49 to 5.50. The Yakju fermented with K1-V1116, La parisienne (black), La parisienne (red) showed high amino acidity levels of 5.59, 5.55 and 5.34, respectively, but that fermented with Fermivin showed a low level of 2.49. EC1118 seemed to be most suitable for producing the dry type of alcoholic beverage because of the low reducing sugar content (0.19%) and soluble solid (7.2 °Brix). The main organic acids in Yakju were succinic acid, lactic acid, citric acid, malic acid and acetic acid. Further, the succinic acid content in Yakju fermented with La parisienne (black), La parisienne (red) was high (about 1,080 mg/L). The main volatile compounds were acetaldehyde, acetic acid and iso-amyl alcohol, and the acetaldehyde and acetic acid contents of the different Yakju samples varied substantially.

This study aimed to find an effective preservation method of lotus leaves for the preparation of lotus-leaf Yakjuthroughout the year. The characteristics of Yakju containing lotus leaves pretreated by blanching, steaming, roasting, and drying were investigated in this study. The chemical properties of Yakju (pH, amino acidity, alcohol content, and volatile acid content) were significantly different for all treatments, except for the total acid content. The polyphenol content ranging from 315.89 to 462.63 ppm (p<0.05) was significantly different depending on pretreatment method L color value for Yakju was not significantly different all treatments, while a value was significantly different in Yakju containing frozen stored leaves after pretreatment. The b value was lowest for the blanching treatment, and was significantly different for all treatments. Among the organic acids present in Yakju, the oxalic, citric, and malic acid contents were significantly different for all treatments. In sensory evaluation, lotus-leaf Yakjus containing fresh leaves and dried leaves were preferred to the others in color and flavor among Yakjus prepared with lotus leaves before cold storage. However, among the Yakjus prepared with lotus leaves after cold storage, that containing blanched leaves was preferred to the others in terms of flavor, taste, and overall acceptability.