• Korean Journal of Food Science and Technology
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• v.52 no.3
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• pp.296-303
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• 2020

Hop-resistant lactic acid bacteria (LAB) are well-known, major beer-spoilage bacteria. The hop-gradient agar containing ethanol (c-HGA+E) method has been used to examine hop-resistance of beer-spoilage LAB. However, the selection of beer-spoilage bacteria by the c-HGA+E method is either too selective or too inclusive. Furthermore, it is accompanied by a complicated experimental procedure, high-cost and time. To overcome these disadvantages, the modified hop-gradient agar with ethanol (m-HGA+E) method was developed. The most remarkable modifications were the shape of the petri dish and the inoculation method for bacteria. The efficiency and validation of the m-HGA+E approach were proven by the formation of colonies at different hop concentrations in the bottom layer, co-culture with the bacteriocin producer and by PCR detection of hop-resistant genes. This study demonstrated that m-HGA+E is a rapid, economical, and easy method to monitor potential hop-resistant beer-spoilage LAB during the beer brewing process.

• Journal of the Korean Society of Food Culture
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• v.30 no.3
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• pp.377-386
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• 2015

The purpose of this research was to appraise physicochemical properties by utilizing different Mit-sool, Juk, Seolgi-tteok, and Godubap, to produce traditional liquor. In all experimental plots, pH and amino acidity tended to increase with duration of fermentation. Titratable acidity displayed a very high number on the second day but then tended to decrease as fermentation progressed. Sugar contents were highest on the fourth day and tended to decrease with time. Alcohol content increased sharply at the initial stage of fermentation and increased gradually. On the 15th day, traditional liquor made with Godubap recorded the highest alcohol content. Common free sugar components were glucose and sorbitol. Common free organic acid components were lactic, succinic, citric, tartaric, malic, and acetic acids. Volatile flavor compounds were six alcohols, five esters, three aldehydes, and two ketones. Regarding overall acceptability in the sensory evaluation, traditional liquor using Seolgi-tteok as Mit-sool scored the highest. Overall, even though different types of Mit-sool had different physicochemical properties, there were no significant differences in volatile flavor compounds or sensory evaluation scores.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.5
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• pp.269-278
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• 2003

Gibberellic acid (GA$_3$) is a commercially important plant growth hormone, which is gaining much more attention all over the world due to its effective use in agriculture and brewing industry. Industrially it is produced by submerged fermentation technique using Ascomycetous fungus Gibberella fujikuroi. Solid state and immobilized cell fermentation techniques had also been developed as an alternative to obtain higher yield of GA$_3$. This review summarizes the problems of GA$_3$ fermentation such as production of co-secondary metabolites along with GA$_3$, substrate inhibition and degradation of GA$_3$ to biologically inert compound gibberellenic acid, which limits the yield of GA$_3$ in the fermentation medium. These problems can be overcome by various bioprocessing strategies e.g. two - stage and fed batch cultivation processes. Further research on bioreactor operation strategies such as continuous and / or extractive fermentation with or without cell recycle / retention system need to be investigated for improvement in yield and productivity. Down stream processing for GA$_3$ isolation is also a challenge and procedures available for the same have been critically evaluated.

• The Korean Journal of Food And Nutrition
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• v.7 no.1
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• pp.51-57
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• 1994

A nuluk, a Korean traditional koji for brewing, was made with wheat flour and Aspergillus usamii mot. shirousamii S1 which had strong abilities in producing amylase and protease. The cultural conditions for the production of saccharogenic and proteolytic enzymes were tested. The productivities of saccharogenic and dextrogenic enzymes were improved when nuluk was made with unsteamed wheat flour as compared with steamed one, but those of proteolytic enzyme and organic acid were reduced. The addition of water containing 0.5% of hydrochloric acid was unfavorable for the production of saccharogenic, dextrogenic and proteolytic enzymes. The optimum ratios of water added to wheat flour for the production of saccharogenic enzyme and proteolytic enzyme were 32% and 28%, respectively on the basis of wheat flour. The optimum temperatures for the production of saccharogenic enzyme and proteolytic enzyme were 36$^{\circ}C$ and 28$^{\circ}C$, respectively. The activity of saccharogenic enzyme reached its maximum after 120 hours of cultivation at 36$^{\circ}C$, but that of proteolytic enzyme 96 hours. The productivity of saccharogenic enzyme was enhanced when the nuluk was molded after 24 hours of precultivation but that of proteolytic enzyme was reduced as compared with no molding.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.6
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• pp.700-709
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• 2014

Recently, a large number of people are growing interested in Korean cuisine and progress Korean culture. This study inverstigated several kinds of Korean traditional alcoholic drinks and brewing methods, including ingredients in ancient culinary manuscripts "Soowoonjabbang", "Eumsikdimibang", "Onjubub", "Jusiksiui", "Uumjeabang" and "Eumsikbangmunnira" of Korean head family. Korean traditional alcoholic drinks were sorted into two groups based on characteristic (danyang ju, yiyang ju, samyang ju, sayang ju, yakyoung ju, gahyang ju, honyang juand soju) and five categories based on preconditioning methods of Korean traditional alcoholic drinks (iporrige, baeksul ki, gumung tteok, godubap, bumbuck). The most announced ancient Korean culinary manuscript is "Onjubub" (57 varieties of Korean traditional alcoholic drinks), the second largest book is "Eumsikdimibang" (49 varieties of Korean traditional alcoholic drinks), and the third highest book is "Soowoonjabbang" (40 varieties of Korean traditional alcoholic drinks). The "Uumjeabang" and "Eumsikbangmunnira" announced 21 and 15 varieties of Korean traditional alcoholic drinks in six books of ancient Korean culinary manuscripts, respectively.

• Mycobiology
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• v.42 no.4
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• pp.353-360
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• 2014

Makgeolli is a traditional Korean alcoholic beverage. The flavor of makgeolli is primarily determined by metabolic products such as free sugars, amino acids, organic acids, and aromatic compounds, which are produced during the fermentation of raw materials by molds and yeasts present in nuruk, a Korean fermentation starter. In this study, makgeolli was brewed using the wild yeast strain Saccharomyces cerevisiae Y98-5, and temporal changes in the metabolites during fermentation were analyzed by ultra-high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry. The resultant data were analyzed by partial least squares-discriminant analysis (PLS-DA). Various metabolites, including amino acids, organic acids, sugar alcohols, small peptides, and nucleosides, were obviously altered by increasing the fermentation period. Changes in these metabolites allowed us to distinguish among makgeolli samples with different fermentation periods (1, 2, 3, 6, 7, and 8 days) on a PLS-DA score plot. In the makgeolli brewed in this study, the amounts of tyrosine ($463.13{\mu}g/mL$) and leucine ($362.77{\mu}g/mL$) were high. Therefore, our results indicate that monitoring the changes in metabolites during makgeolli fermentation might be important for brewing makgeolli with good nutritional quality.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.23-23
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• 2014

There are many yeast strains have been discovered for industrial usage in global scale. In the point of view for the alcoholic fermentation performance and producing alcoholic beverage products, recently many countries have known about the importance of microorganisms as a valuable resource. Discovered with well performed yeasts have potential industrial application in diverse ways such as foods, beverages, cosmetics, pharmaceutical functions, and so on. In Korea, the yeast research has not been sufficiently performed especially for distilled spirits industry. As a result, not so little manufacturers use exotic yeasts from overseas even included the expensive royalties. Besides of those, to produce distilled spirits, many manufacturers do not use specialized yeast for distilled spirits. Distiller's characterized yeasts such as whisky, brandy, vodka, Japanese shochu and awamori, are all well-known industrialized. For decades, the distillers, except us, have selected, developed, and practised yeasts in accordance with distilled spirits characters. This study is about selection and industrial application of yeasts for the Korean pot distilled spirits. Finally 7 yeast strains were selected among over 1,000 yeasts from the traditional Nuruks, through the essential related tests based on brewing and distilling science. The selected yeasts show the appropriate characteristics of distilled spirits. The result of this study could help our distilled spirits industry be activated and stand independent from the exotic microbes.

• The Korean Journal of Food And Nutrition
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• v.12 no.3
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• pp.219-225
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• 1999

In order to improve the quality of nuruk a Korean traditional fermenting agent for brewing nuruk was modified by a new method inoculating Rhizopus japonicus T2 Aspergillus oryzae L2 and hansenula sp. BC26 which had been isolated from traditional Nuruk. And the characteristics of modified Nuruk were investimgated as compared with current fermenting agents such as commercial Nuruk and rice koji of As-pergillus kawachii. The odor of modified Nuruk was savory but those of commercial Nuruk and rice koji were fetid andinodorous repectively. The extracted waters of modified Nuruk commercial Nuruk and rice koji were yellow pale yellow and colorless and showed 6.15, 6.01 and 3.30 of pH respectively. Mod-ified Nuruk had 7.6${\times}$106CFU/g of yeast but commercial uruk and rice koji had no yeast. Commercial Nuruk had 1.0${\times}$102CFU/g of lactic acid bacteria but modified Nuruk and rice koji had no lactic acid bacteria. The amylolytic and proteolytic activities of modified Nuruk were much higher than those of commercial Nuruk or rice koji. Seed mash of modified Nuruk had ester aroma but that of commercial Nuruk rather offensive odor and that of rice koji neither ester aroma or offensive odor. It seemed that if the modified Nuruk is used in seed mashing the supplement of acidulant is need to lower pH. The quality of modified Nuruk was thought to be much better than that of commercial Nuruk or rice koji.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.46-50
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• 2003

In order to develop a new variety of rice that adapts to the climate of Aomori prefecture and possesses characteristics suitable for production of high quality Japanese sake, artificial cross experiments were executed between Yamadanishiki, which is widely used nationwide as an authentic variety of rice for sake production, and Hanafubuki, which was peviously developed by Aomori prefecture. An excellent hybrid, named Hanaomoi, was selected and fixed by a series of selection experiments and systematic cultivation. Unpolished Hanaomoi rice contained less amount of protein than Yamadanishiki and Hanafubuki. Unpolished rice of Hanaomoi was harder than Yamadanishiri and Hanafubuki, therefore polishing treatment was done in high yield and one could obtain a high degree of polish on the rice(namely 40% polishing). These features are advantageous to production of high quality of sake.Test brewing using 40% polished Hanaomoi gave rise to a characteristic sake that contained a slightly higher amount of alcohol and flavor components than Yamadanishiki and Hanafubuki. Sensory tests concluded that sake from Hanaomoi was as superior as the one from authentic Yamadanishiki. Hanaomoi is a promising variety of rice suitable for production of a high quality sake exclusive to Aomori prefecture.

• KSBB Journal
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• v.30 no.1
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• pp.33-37
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• 2015

Recently, several health benefits of rice wine, makgeolli, were known due to the interest on the traditional Korean liquor and the researches on the rice wine are increasing. Organic acids produced during the process of rice wine fermentation play important roles in the taste and flavor. In this study, we have examined the optimal conditions for lactic acid production in rice koji as a carbon source. Skim milk was also used as a supplementary ingredient for the optimization of lactic acid fermentation. Bacterial growth of Lactobacillus sakei was monitored under this condition. The pH, acidity of the culture and the ethanol tolerance of this bacterium were also tested. Through these experiments, we were able to optimize the growth condition of lactic acid bacteria by the addition of skim milk. This was also able to affect the change of pH, acidity, sugar concentration and alcohol tolerance, which might contribute to the improvement of the quality of rice wine. The optimal condition for the growth was 2 days with 10% (w/v) of skim milk concentration. With these results, it was confirmed that rice koji was an effective carbon source for the growth of lactic acid bacteria.