• Journal of Microbiology and Biotechnology
• /
• 제17권2호
• /
• pp.297-304
• /
• 2007

The effect of yeast propagated at different aeration conditions on yeast physiology, fermentation ability, and beer quality was investigated using three strains of Saccharomyces cerevisiae. It was shown that yeast cells grown under continuous aeration conditions during propagation were almost two times higher as compared with discontinuous aeration conditions. The maximum of cell growth of all samples reached between 36 hand 48 h. The concentration of trehalose was increased under continuous aerated yeasts, whereas glycogen was decreased. It was also observed that the concentration of glycogen and trehalose in yeast cells had no direct effect on subsequent fermentation ability. The effect of yeast propagated under different aeration conditions on subsequent fermentation ability was different from yeast strains, in which the influence will be most pronounced at the first fermentation. Later, the yeasts might regain its original characteristics in the following fermentations. Generally, continuously propagated yeast had a positive effect on beer quality in subsequent fermentation. Hence, the concentration of aroma compounds obtained with yeast propagated under 6 1/h for 48 h aeration was lower than those grown under other aeration conditions in the bottom yeasts; in particular, the amounts of phenylethyl alcohol, ester, and fatty acids were decreased.

• Food Science and Biotechnology
• /
• 제18권5호
• /
• pp.1109-1117
• /
• 2009

This study was conducted to examine the chemical and sensory characteristics of fermented worts and consumer acceptability according to added flavorings. The worts were fermented by yeast (Saccharomyces cerevisiae) following fermentation by lactic acid bacteria (Leuconostoc citreum) at different aeration conditions. Chemical and sensory descriptive analyses were conducted to examine the effects of the fermentation conditions. The consumer acceptability of the worts with added flavorings was also examined. Organic acids, functional sugars, and ethanol were produced by L. citreum and S. cerevisiae, respectively. Ethanol concentrations ranged from 10 to 25 g/L depending on the fermentation conditions. The sensory characteristics of the fermented worts were clearly differentiated by the fermentation conditions. Yeast fermentation resulted in high intensities for certain sensory attributes such as 'alcohol', 'fermented barley', 'fermented white grape', and 'grassy'. Consumer acceptability changed with different levels of sugar and lemon flavoring, and the optimum levels were determined as 14.08% sugar and 0.98% lemon flavoring. Under these conditions, it was shown that a relatively acceptable fermented wort beverage containing functional materials can be produced.

• 한국식품영양학회지
• /
• 제33권5호
• /
• pp.512-523
• /
• 2020

The objective of this study was to investigate the quality characteristics of Cheongsoo wine using freeze concentration fermented with 5 kinds of yeast strains (Saccharomyces cerevisiae EJ18, EJ30, HK22, HK32 and Fermivin). We compared the characteristics, volatile flavor component and physiological activity of 5 wines. The freeze concentration can increase the sugar concentration in grape juice by reducing its water content and the alcohol content of freeze-cententrated Cheongsoo wines ranged between 15.0~15.8%. The pH of wines ranged from 2.92 to 2.94 and the total acidity and soluble solid of wines ranged from 12.40~13.27. °Brix. The major organic acid in the wines was tartaric acid (4.49~5.11 mg/mL) and malic acid (7.00~7.97 mg/mL). It contains higher functional compounds in wine fermented with yeast (EJ18, EJ30, HK22, HK32) than wine fermented with fermivin. α-glucosidase and tyrosinase inhibitory activity had the highest values (78.87% and 62.25%) in wine fermented with HK22 and EJ18 yeast, respectively. 16 volatile flavor compounds (alcohols, esters, ketones, acids, and others) were detected in the Cheongsoo wines by freeze concentration. These results provide useful information that the quality characteristics of wine developed by the freeze-concentration method using grapes cultivated in Korea.

• 미생물학회지
• /
• 제43권3호
• /
• pp.217-221
• /
• 2007

거봉 포도로부터 분리하여 동정한 야생효모 Saccharomyces cerevisiae IJ850을 이용, 국내산 캠벨얼리와 거봉포도를 발효시켜 적포도주를 제조하고, 이의 발효특성을 분석함으로서 포도주제조용 발효균주로서의 가능성을 알아보고자 하였다. 야생발효균주의 분리를 위하여 안성지역 거봉포도와 캠벨얼리 포도즙을 실온에서 6일 동안 스타터의 첨가없이 자연발효시켜 우세균주를 분리하였다. 거봉에서 분리된 효모의 발효능이 캠벨얼리에서 분리된 효모보다 1.8배정도 높았다. 거봉에서 분리한 발효균주를 분자 생물학적 인 방법 인 26S rDNA 염기서열에 근거하여 동정한 결과, Saccharomyces cerevisiae와 99.7%의 유사성을 나타내어 Saccharomyces cerevisiae IJ850으로 동정되었다. 분리균주를 이용한 포도주의 제조에서는 캠벨얼리와 거봉포도즙의 최종 당도를 $25^{\circ}Brix$로 포도당을 이용하여 보당하고, 이산화탄소를 발효조에 채우고, 실온에서 10일간 발효시켰다. 포도주의 수율은 캠벨얼리가 75%, 거봉이 85%였고 최종 알코올 도수는 캠벨얼리가 11.0%, 거봉이 13.0%이었다. 산업용발효균주인 S. cerevisiae EC-1118과 비교한 결과 총산도는 캠벨얼리와 거봉포도주 모두에서 산업용 발효균주인 EC-1118에 비하여 분리한 S. cerevisiae IJ850에서 낮은 수치를 보였다. 포도주의 pH와 색도 분석에서는 S. cerevisiae IJ850과 S. cerevisiae EC-1118로 제조한 포도주모두에서 비슷한 수치를 보여주었으나, 페놀 성분분석에서는 S. cerevisiae EC-1118로 제조한 캠벨얼리 포도주에서 125 mg/L의 함량을, S. cerevisiae IJ850으로 제조한 거봉포도주에서 75 mg/L의 함량을 나타내었다. 따라서 국내 거봉포도로부터 분리한 S. cerevesiae IJ850는 포도주 생산에 사용될 수 있는 균주로써 그 가능성을 보여주었다.

• 동아시아식생활학회지
• /
• 제23권5호
• /
• pp.546-560
• /
• 2013

In this study, a natural fermentation starter formulation was developed for manufacturing Korean bread products by substituting baker's yeast with naturally fermented blueberry starters. As the incubation time of the blueberry extracts increased, the pH and total titratable acidity increased. The sweetness (brix%) of blueberry extracts containing various amounts of sugar were higher than the other sample. The result of alcoholicity for naturally fermented blueberry extracts, the fermented blueberry extract containing 20% sugar was highest. Lactic acid bacteria counts increased until the 4th day; however, it decreased from the 5th day, and viable yeast counts increased consistently until the 5th day. The volume for naturally fermented blueberry extracts increased as the incubation time increased. As the fermentation time of blueberry starters increased, the pH of bread dough decreased. The RVA analysis conveyed that wheat flour retrogradation was retarded by increasing the blueberry starter content. The weight of pan breads containing blueberry starters were higher than that of the control, while the volume, specific volume and baking loss rate were lower than those of the control. The moisture content of pan breads containing blueberry starter decreased as storage time increased. In analyzing the visible mold colony during 7 days of storage at $28^{\circ}C$, mold growth in pan breads containing the blueberry starter was retarded. The hardness of breads containing blueberry starters were significantly increased as storage time increased. The breads containing 50% naturally fermented blueberry starter have acceptable sensory properties. In conclusion, these results indicated that 50% of natural fermentation blueberry starter could be very useful as a substitute for yeast when making naturally fermented bread.

• 한국식생활문화학회지
• /
• 제30권4호
• /
• pp.475-480
• /
• 2015

Jeju citrus, which contains an abundance of calcium and vitamin, was used to develop fermented citrus peel extract. A total of seven probiotic strains were applied to tangerine dermis to select the best growing bacteria in citrus peel extracts. B. longum, B. bifidum, and L. mesenteroides were found to grow best in citrus peel extract culture containing glucose, yeast extracts, peptone, and potassium phosphate. Citrus peel extract culture consisting of 1% yeast extract, 5% peptone, and 0.1% phosphate was the best environment for growth of probiotics. The pH, acidity, and viable cell numbers of these fermented extracts were measured. The initial pH level of fermented extracts with nutrients was 5.25 and dropped rapidly to 3.39 after 72 hours of fermentation. The acidity of fermented extracts increased to 4.08 % after 72 hours of fermentation, and the viable cell number in fermented extracts after refrigeration for 2 weeks was $1.3{\times}10^{10}CFU/mL$. The antimicrobial activity of citrus peel fermented extracts against Campylobacter jejuni was determined, and concentrations more than 25,000 ppm showed antimicrobial activity.

• 동아시아식생활학회지
• /
• 제18권1호
• /
• pp.87-94
• /
• 2008

In this study, a nanatural fermentation starter formulation was developed for manufacturing bread products by substituting baker's yeast with naturally fermented raisin extract and sourdough. Four experimental groups containing 2.5, 5.0, 7.5, 10% naturally fermented raisin extract per 2,000 g of flour were compared based on quality characteristics, including the fermentation power on dough expansion, specific volume, baking loss, water activity, color, textural characteristics, and internal surface appearance. The activities of the naturally fermented raisin extract were examined in terms of pH changes, total titratable acidity, brix, and viable yeast counts. The raisin extract, which was cultured for 7 days at 30$^{\circ}C$, smelled of alcohol and produced $CO_2$. Yeast were also found in the extract after separation. As the incubation time of the raisin extract and sourdough increased, pH decreased, while total titratable acidity increased. The brix of the raisin extract increased until the $2^{nd}$ day of fermentation, and viable yeast counts increased until the $5^{th}$ day however, these gradually decreased by the $7^{th}$ day. The fermenting power on dough expansion increased in the bread with increasing incubation time. The bread samples containing 7.5% and 10% raisin extract had significantly higher specific volumes than the other samples. Baking loss was minimal with the 2.5% extract substitution. In analyzing the crumb, water activity, redness, and yellowness were highest in the 10.0% raisin extract bread samples, and lightness was maximal in the 5.0% group. In terms of textural characteristics, hardness was lowest with the 2.5% extract substitution. Gumminess, springiness, and chewiness were not significantly different among the bread samples. Cohesiveness was highest at the 7.5% extract substitution level, and resilience was lowest at the 10% level. In conclusion, based on the results, a natural fermentation starter formulated with 2.5% naturally fermented raisin extract (1 part raisins and 1.5 parts water) and 70% sourdough (1 part rye flour and 1 part water) has high potential as a baker's yeast substitute for making naturally fermented bread.

• 한국식품과학회지
• /
• 제52권5호
• /
• pp.529-537
• /
• 2020

본 연구에서는 재래누룩을 사용한 막걸리의 미생물 군집을 차세대 염기서열 분석기법(NGS)을 활용하여 조사하고, 미생물 군집이 막걸리의 품질에 미치는 영향을 구명하고자 효모 첨가에 따른 품질특성을 확인하였다. 발효 스타터로 효모의 첨가는 재래누룩 막걸리의 미생물 군집 분포에 영향을 주어 결과적으로 막걸리의 품질 차이를 나타냈다. 무첨가구의 경우 발효 초기의 진균류는 Saccharomycopsis fibuligera가 대부분이었고, 세균류는 Pediococcus pentosaceus, Weissella confusa, Pantoea vagans의 증식으로 인하여 총산 및 젖산 함량이 높게 나타났다. 첨가구는 발효 시작 전부터 Saccharomyces cerevisiae가 우점하여 알코올 생성 속도가 빠르고, 발효 초기의 높은 알코올 농도로 인해 재래누룩에서 기인한 젖산 생성 bacteria의 생육을 억제하는 것으로 나타났다. 따라서 재래누룩으로 막걸리를 제조할 때, 알코올 생성능이 우수한 효모의 첨가가 막걸리 시어짐의 원인이 되는 젖산균의 성장을 억제함으로써 산미를 낮추고 제품의 균일성을 확보할 수 있을 것으로 판단된다.

• Journal of Animal Science and Technology
• /
• 제47권4호
• /
• pp.607-614
• /
• 2005

본 시험은 맥주박의 알코올 발효가 발효특성 및 사료의 영양적 가치에 미치는 영향을 검토하기 위하여 실시하였다. 본 시험에 이용한 시험사료는 맥주박과 파쇄 옥수수를 50:50(풍건상태)의 비율로 혼합하여 혐기 발효에 의하여 발효사료를 제조하였다. 발효 조건은 당밀 첨가 수준(0, 2 및 5%), yeast 첨가 수준(0, 0.1, 0.5, 1.0 및 2.0%) 및 발효 온도(4, 10, 30, 40 및 50$^{\circ}C$)에 따른 변화를 검토하였으며, 각 조건에 의한 알코올 함량, live yeast cell number (LYCN) 및 pH 변화를 조사하였다. 당밀 첨가에 따른 알코올 함량은 첨가수준이 증가할수록 높게 생성되었다. 발효 24시간 동안에 yeast 0.1, 0.5, 1.0 및 2.0% 첨가에 따른 알코올 함량은 각각 1.9, 2.4, 3.1 및 3.1%로 나타나, yeast 첨가수준 1% 까지는 yeast의 첨가수준이 증가할수록 시험사료중의 알코올 생성량도 비례적으로 증가하였으나(P<0.05), yeast 첨가수준 1.0 이상에서는 일정한 양의 알코올 이 생성되었다. 발효 초기의 LYCN은 yeast 첨가수준이 높을수록 높게 나타났으나(P<0.05), 발효 48시간 후의 LNCN은 0.1% 이하에서는 유의적으로 낮게 나타났다(P<0.05). 발효 온도에 따른 알코올 생성량은 발효 온도 30 및 40$^{\circ}C$에서 유의적으로 높은 결과를 보였으며(P<0.05), 30$^{\circ}C$와 40$^{\circ}C$ 간의 알코올 생성량은 30$^{\circ}C$에서 높은 경향이었다. 발효 온도에 따른 pH는 발효 온도가 낮을수록 발효 24시간까지 급격히 감소하는 것으로 나타났다(P<0.05). 이상의 결과로 미루어 맥주박의 사료적 가치를 높이기 위해 yeast의 첨가량, 당밀(발효기질), 발효온도 및 발효시간 등의 요인을 고려하였을 경우, 본 시험의 조건하에서 원활한 알코올 발효와 발효사료의 품질을 향상시키기 위한 적정 발효조건은 당밀 5%와 yeast 1%를 첨가하여 30$^{\circ}C$에서 24시간 동안 발효시키는 것이 가장 바람직한 것으로 나타났다.

• 한국식품영양과학회지
• /
• 제27권6호
• /
• pp.1059-1064
• /
• 1998

Fermented beverage using lactic acid bacteria isolated from kimchi was investigated. Lactic acid bacteria KL 1, KD 6, KL 4 strains from kimchi, or obtained Lactobacillus acidophilus, Lactobacillus plantarum, Leuconostoc mesenteroides with and without yeast(Saccharomyces cerevisiae) were inoculated in fruit vegetable juice for single and mixed culture fermentation. During the fermentation by bacterial strain and yeast for 1~3 days at 30oC, various fermentation behaviors were observed. The growth rate of mixed culture of KL 1 and yeast was higher than that of single culture by KL 1 alone during the fermentation. The amount of organic acid produced by the mixed culture fermentation of KL 1 and yeast was 0.82%(3 day) or 0.58%(1 day) and with the final pH of 3.3(3 day) or 4.2(1 day). These mixed culture systems of isolated strains or other bacterial strains had almost similar results of growth rate and acid production. Among several bacterial strains, KL 1 was suitable for the mixed culture fermentation with yeast in terms of desirable fermentation behavior and organoleptical quality. The selected strain, KL 1 was identified as Leuconostoc spp. through the series of tests on carbohydrate fermentation and biochemical characteristics.