• The Korean Journal of Food And Nutrition
• /
• v.27 no.5
• /
• pp.851-858
• /
• 2014

Goami2, Goami3 and Goami4 were identified as fiber-rich rice cultivars which were developed by mutation breeding with Ilpum. The purpose of this study was to develop a method for producing Makgeolli with the fiber-rich rice cultivars, Goami2, Goami3, Goami4, and to investigate the characteristics of Makgeolli during the fermentation process. Makgeolli was produced herein by fermentation steamed rice (SR), raw rice flour (RF), and steamed rice flour (SF) from Goami2, Goami3, Goami4, Ilpum and Sealgaeng rice cultivars. The physicochemical characteristics including alcohol and sugar content, pH, total acidity, TDF (total dietary fiber), and color of the Makgeolli samples were analyzed. Makgeolli produced with Ilpum and Sealgaeng showed satisfactory fermention characteristics in alcohol and sugar content when SR, RF and SF were used. In the case of Goami2, Goami3, and Goami4, the use of SF resulted in 17.2~20.1% alcohol content, whereas only 10% alcohol was produced by SR. The sugar contents in the SF-makgeolli samples were also higher ($9{\sim}10^{\circ}Brix$) than in the SR-makgeolli ($5.35{\sim}5.44^{\circ}Brix$) for Goami2 and Goami4 cultivars. The dietary fiber contents of the Makgeolli samples produced using SF from the fiber-rich rice cultivars were higher (1.35~1.52 g/100 mL) than those produced with Ilpum and Sealgaeng (0.74~0.87 g/100 mL). From these results, it may be suggested that SF would be an appropriate material to brew Makgeolli using fiber-rich rice cultivars to obtain better physicochemical and functional qualities.

• 한국균학회소식:학술대회논문집
• /
• 2015.11a
• /
• pp.11-11
• /
• 2015

A total of sixty-six samples of Nuruk, a fermention starter used to make the Korean traditional rice wine, Makgeolli, were collected from central and southern regions of Korea in 2013 and 2014. We classified two groups of the Nuruk samples, "commercial" and "home-made", according to the manufacturing procedure and purpose of use. Commercial Nuruks were made in a controlled environment where the temperature and humidity are fixed and the final product is supplied to Makgeolli manufacturers. Home-made Nuruks were made under uncontrolled conditions in the naturally opened environment and were intended for use in the production of small amounts of home-brewed Makgeolli. We obtained more than five hundred isolates including filamentous fungi and yeasts from the Nuruk samples followed by identification of fungal species. Also we stored glycerol stocks of each single isolate at $-70^{\circ}C$. We identified the species of each isolate based on the sequences of ITS regions amplified with two different universal primer pairs. We also performed morphological characterization of the filamentous fungi and yeast species through observations under the microscope. We investigated the major fungal species of commercial and home-made Nuruks by counting the colony forming units (CFU) and analyzing the occurrence tendency of fungal species. While commercial Nuruks contained mostly high CFU of yeasts, home-made Nuruks showed relatively high occurrence of filamentous fungi. One of the representative Nuruk manufacturers used both domestic wheat bran and imported ones, mainly from US, as raw material. Depending on the source of ingredient, the fungal diversity was somewhat different. Another commercial Nuruk sample was collected twice, once in 2013 and again in 2014, and showed different diversity of fungal species in each year. Nuruks obtained from the southern regions of Korea and Jeju island showed high frequency of yeast such as Saccharomycopsis fibuligera and Pichia species as well as unique filamentous fungus, Monascus species. S. fibuligera was easily found in many Nuruk samples with high CFU. The major filamentous fungi were Aspergillus, Lichtheimia, Mucor and Penicillium species. In order to further our understanding of the isolates and their potential industrial applications, we assayed three enzymes, alpha amylase, glucoamylase and acid protease from 140 isolates out of about five hundred isolates and selected about 10 excellent strains with high enzyme activities. With these fungal isolates, we will perform omics analyses including genomics, transcriptomics, metabolic pathway analyses, and metabolomics followed by whole genome sequencing of unique isolates associated with the basic research of Nuruk and that also has applications in the Makgeolli making process.

• Applied Biological Chemistry
• /
• v.38 no.3
• /
• pp.191-195
• /
• 1995

Production of a high viscosity exoploysaccharide, methylan, by Methylobacterium organophilum from methanol was carried out in fed-batch cultures and the rheological properties of methylan fermentation broth were studied. Bacterial biomass showed little influence on viscosity, but the accumulation of methylan caused the increase of viscosity. With proceeding fermention, the viscosity at the same concentration of methylan was significantly increased and methylan solution showed slightly higher pseudoplasticity. The composition changes of methylan were investigated at various fermentation times. Contents of total sugar, reducing sugar and methylan were decreased but contents of acids(pyruvic acid, uronic acid and acetic acid) were increased with the culture time. It was considered that the increased content of acids resulted in the increase of the hyrodynamic domain in the solution due to charge repulsion. Consequently, the solution viscosity increased in propotion to the acids contents of methylan. Cell growth and methylan production were severely decreased by the limitation of dissolved oxygen. However, the cellular activity for methylan production was almost constant regardless of the level of dissolved oxygen. As a result, the high speed of agitation increased the methylan production, the specific production rate of methylan, and the methylan yield of the cell.

• The Korean Journal of Food And Nutrition
• /
• v.18 no.1
• /
• pp.94-101
• /
• 2005

The present study was conducted to know the physicochemical properties of Korean tea according to degree of fermention. The moisture content of green tea, blue tea, yellow tea and black tea was 2.02∼2.04%. The content of total nitrogen was 3.78 % in green tea and 3.49∼4.03% in fermented tea. The content of the mineral was highest in Ca, Mg. The content of vitamin C was 670.62 mg in green tea and 169.7∼85.03 mg in fermented tea. The content of vitamin C were increased as tea was more fermented. The composition of vitamin E and β-carotene was green tea> blue tea> yellow tea> black tea. The content of the rutin was 0.12 % in green tea and 1.37% in black tea. The content of rutin was increased with fermentation. The content of total amino acid of green tea was 2270.9 mg. The content of main amino acid of Glu, Asp, and Leu was 342.01 mg, 165.32 mg, and 161.69 mg and the hightst content of Glu. The content of total amino acid of black tea was 2,219.08 mg. Total amino acid content of fermented tea increased in the order of black tea> blue tea> yellow tea, and among the tea, the content of black tea was the highest in the fermented tea. The content of caffeine was 1.17% in green tea and 1.05∼1.32% fermented tea. These results were nothing in the content of caffeine during the fermentation. The content of theanine was 0.95% in green tea and 0.73∼1.42% in fermented tea. The content of total catechin was highest in green tea, and decreased sharply as tea was more fermented. Flavonoid content of 1.05% in green tea. DPPH radical scavenge activities of the teas 4.73∼19.5% mg.

• The Korean Journal of Food And Nutrition
• /
• v.13 no.4
• /
• pp.319-327
• /
• 2000

This study was conducted to prolong the edible period of Kimchi by adding chitosan (0.25, 0.5%) and sodium salts of various organic acids(0.01~0.04M citrate, malate, lactate) . The edible period was estimated by measuring changes in pH. titratable acidity(TA), PH/TA ratio, ascorbic acid content and pectin fraction during Kimchi fermentation at 2$0^{\circ}C$. The results were compared by estimating the maturity of Kimchi fermentation. Kimchi with the chitosan showed higher pH and titratable acidity throughout the fermentation period than that without chitosan. The pH decreased during the fermentation in the order of control, 0.25% chitosan, 0.5% chitosan, 0.5% chitosan+Na-citrate, 0.5% chitosan+Na-malate and 0.5% chitosan+Na-lactate. But the titratable acidity increased in the order of control, 0.5% chitosan+Na-malate, 0.25% chitosan. 0.5% chitosan+Na-citrate, 0.5% chitosan and 0.5% chitosan+Na-lactate. The PH/TA ratio decreased in the order of control, 0.25% chitosan, 0.5% chitosan+Na-malate, 0.5% chitosan, 0.5% chitosan+Na-citrate and 0.5% chitosan+Na-lactate. Ascorbic acid content in Kimchi was the highest at the 3rd day and then decreased during fermentation. Ascorbic acid content in Kimchi containing 0.5% chitosan and organic acid salts was higher than others. Alcohol insoluble solids( AIS ) in Kimchi decreased during fermentation in the order of control, 0.25% chitosan, 0.5% chitosan, 0.5% chitosan+Na-palate. 7.5% chitosan+Na-lactate and 0.5% chitosan+Na-citrate. During fermentation, hot water soluble pectin (HWSP) of control increased, whereas HCI soluble pectin (HCISP) decreased. By addition of chitosan, however, the results became reverse. Chitosan addition appeared to be effective in improving preservation quality of Kimchi during fermention. The edible period become extended by using chitosan plus organic acids instead of using chitosan only. Overall. addition of 0.5% chitosan+Na-lactate seemed most effective in prolonging the edible periods during Kimchi fermentation.