This study was carried out to establish optimal conditions of air-blast drying to increase survival rate of indigenous non-Saccharomyces Yakju yeast starters which can be helpful for the development of Korean traditional liquor industry. Six non-Saccharomyces yeast strains were selected among 500 ye...
This study was carried out to establish optimal conditions of air-blast drying to increase survival rate of indigenous non-Saccharomyces Yakju yeast starters which can be helpful for the development of Korean traditional liquor industry. Six non-Saccharomyces yeast strains were selected among 500 yeasts (isolated from persimmon, apple, grape, aronia and Nuruk) in accordance with previous research identifying volatile ester compounds and sensory evaluation of Yakju. The strains were identified to be Wickerhamomyces anomalus N249, Wickerhamomyces anomalus A159, Pichia kudriavzevil N373, Pichia kudriavzevil N376, Torulaspora delbrueckii N381, Hanseniaspora vineae G818 as Yakju starters. Experiments were conducted for the optimization of protectant and rehydration conditions using different types of sugars and rehydration solutions to enhance the viability of air-blast dried yeast cells. Six types of sugars (fructose, glucose, maltose, raffinose, sucrose, trehalose) and four types of rehydration solutions (distilled water, 1× phosphate buffered saline, 0.85% NaCl, and 1% peptone water) were examined to investigate optimal air-blast drying conditions to increase the survival rate about non-Saccharomyces yeasts. The whole mixture containing protectant, excipient and each strain was air-blast dried at 37℃ for 15-60 min until the moisture content was 10±2%. Among these 6 non-Saccharomyces yeasts, P. kudriavzevii N373 and W. anomalus A159, as a result of the enzyme activities analysis and sniffing test, were selected as the final non-Saccharomyces yeasts suitable for brewing the Yakju. In addition, S. cerevisiae W153 with the best fragrance productive ability was selected as the Saccharomyces yeast according to the previous study. Yakju was made using these strains, and non-Saccharomyces strains (N373, A159) were co-fermented with a S. cerevisiae W153 at a ratio of 9:1. As a control strain, S. cerevisiae W-3 was used. Furthermore, the ratio of glutinous rice was one of the experimental conditions, and the conditions were set at 100% and 50% of glutinous rice to each co-fermentation sample.
As a result of rehydration immediately after air-blast drying, P. kudriavzevii N373 and T. delbrueckii N381 showed the highest survival rates of 121.21% and 114.33% when rehydrated with distilled water in presence of fructose as a protectant. W. anomalus A159 and N249 showed the highest survival rates of 113.20% and 117.02% when rehydrated with 1% peptone water and 1× PBS buffer, respectively in presence of trehalose as a protectant. P. kudriavzevii N376 showed the highest survival rate of 158.81% when rehydrated with 1× PBS buffer in presence of glucose as a protectant. H. vineae G818 showed the highest survival rate of 152.48% when rehydrated with 0.85% NaCl solution in presence of raffinose as a protectant. Moreover, change of cell viability was investigated by rehydrating these yeasts that stored at 4℃ for 2 months. As a result of rehydration after 2 months, N373, G818 and N381 showed the highest survival rates of 109.85%, 106.86% and 80.37% when rehydrated with distilled water (N373, G818) and 0.85% NaCl solution (N381), respectively in presence of fructose as a protectant. N376 and N249 showed the highest survival rates of 67.78% and 9.41% when rehydrated with 1% peptone water and 1× PBS buffer, respectively in presence of glucose as a protectant. A159 showed the highest survival rate of 43.54% when rehydrated with 1× PBS buffer, in the presence of maltose as a protectant. In conclusion, fructose and trehalose were most effective as protectants in most strains, and 1× PBS buffer and 0.85% NaCl solution as rehydration solutions were most effective in some strains, respectively.
As fermentation characteristics of Yakju, the soluble solid, reducing sugar and total phenolic compounds was similar concentration under all conditions. In case of the pH, the pH of sample brewed with 100% glutinous rice (GR) was slightly higher than that of the sample brewed with 50% glutinous rice and 50% non-glutinous rice (GR+NGR). On the other hand, the total acid was higher in GR+NGR than in GR. In case of the alcohol, alcohol content of GR was higher than that of GR+NGR, and the alcohol of the single fermented sample was higher than that of the co-fermented sample up to the third day of fermentation. However, final alcohol ranged from 18.6-19.2% under all conditions similarly. In case of the single fermented samples, the viable cell count increased drastically at the beginning of fermentation, and maintained or reduced gradually after the third day. Viable cell count of the co-fermented samples was lower than that of single fermented samples until the 8th day of fermentation, but it was generally higher than that of the single-fermented samples at the end of fermentation. In addition, the final viable cell count of W153 single fermented sample with GR+NGR was the highest, so alcohol content was the highest in this sample. Organic acids were produced in the order of citric acid, succinic acid, malic acid, acetic acid, and lactic acid. Free sugar was detected only glucose as the residual sugar in all samples. Analysis of volatile aromatic compounds found that esters were 13 types, alcohols were 4 types, and sulpur compounds was 1 type. Total ester contents of co-fermented samples were generally higher than those of single-fermented samples. In particular, the content of 2-phenethyl acetate of W153+A159 co-fermented sample with GR+NGR was twice as high as that of W-3 single-fermented sample used as a control, and the 2-phenethyl acetate contents of W153+N373 appeared high under all conditions. In sensory evaluation, the flavor and sweetness scores were the highest in the co-fermentation of W153+A159 with GR+NGR, so overall preference score was also the highest in it.
In this study, optimal air-blast drying conditions of non-Saccharomyces Yakju yeast starters were investigated to make powder form and selected low-temperature tolerant non-Saccharomyces yeasts among these strains were co-fermented with S. cerevisiae to enhance fragrance of Yakju. In addition, the characteristics of Yakju were analyzed according to the amount of glutinous rice added. Consequently, this study would make for the development of Korean fermentation starter industry and high-quality Yakju with various volatile aroma components.
This study was carried out to establish optimal conditions of air-blast drying to increase survival rate of indigenous non-Saccharomyces Yakju yeast starters which can be helpful for the development of Korean traditional liquor industry. Six non-Saccharomyces yeast strains were selected among 500 yeasts (isolated from persimmon, apple, grape, aronia and Nuruk) in accordance with previous research identifying volatile ester compounds and sensory evaluation of Yakju. The strains were identified to be Wickerhamomyces anomalus N249, Wickerhamomyces anomalus A159, Pichia kudriavzevil N373, Pichia kudriavzevil N376, Torulaspora delbrueckii N381, Hanseniaspora vineae G818 as Yakju starters. Experiments were conducted for the optimization of protectant and rehydration conditions using different types of sugars and rehydration solutions to enhance the viability of air-blast dried yeast cells. Six types of sugars (fructose, glucose, maltose, raffinose, sucrose, trehalose) and four types of rehydration solutions (distilled water, 1× phosphate buffered saline, 0.85% NaCl, and 1% peptone water) were examined to investigate optimal air-blast drying conditions to increase the survival rate about non-Saccharomyces yeasts. The whole mixture containing protectant, excipient and each strain was air-blast dried at 37℃ for 15-60 min until the moisture content was 10±2%. Among these 6 non-Saccharomyces yeasts, P. kudriavzevii N373 and W. anomalus A159, as a result of the enzyme activities analysis and sniffing test, were selected as the final non-Saccharomyces yeasts suitable for brewing the Yakju. In addition, S. cerevisiae W153 with the best fragrance productive ability was selected as the Saccharomyces yeast according to the previous study. Yakju was made using these strains, and non-Saccharomyces strains (N373, A159) were co-fermented with a S. cerevisiae W153 at a ratio of 9:1. As a control strain, S. cerevisiae W-3 was used. Furthermore, the ratio of glutinous rice was one of the experimental conditions, and the conditions were set at 100% and 50% of glutinous rice to each co-fermentation sample.
As a result of rehydration immediately after air-blast drying, P. kudriavzevii N373 and T. delbrueckii N381 showed the highest survival rates of 121.21% and 114.33% when rehydrated with distilled water in presence of fructose as a protectant. W. anomalus A159 and N249 showed the highest survival rates of 113.20% and 117.02% when rehydrated with 1% peptone water and 1× PBS buffer, respectively in presence of trehalose as a protectant. P. kudriavzevii N376 showed the highest survival rate of 158.81% when rehydrated with 1× PBS buffer in presence of glucose as a protectant. H. vineae G818 showed the highest survival rate of 152.48% when rehydrated with 0.85% NaCl solution in presence of raffinose as a protectant. Moreover, change of cell viability was investigated by rehydrating these yeasts that stored at 4℃ for 2 months. As a result of rehydration after 2 months, N373, G818 and N381 showed the highest survival rates of 109.85%, 106.86% and 80.37% when rehydrated with distilled water (N373, G818) and 0.85% NaCl solution (N381), respectively in presence of fructose as a protectant. N376 and N249 showed the highest survival rates of 67.78% and 9.41% when rehydrated with 1% peptone water and 1× PBS buffer, respectively in presence of glucose as a protectant. A159 showed the highest survival rate of 43.54% when rehydrated with 1× PBS buffer, in the presence of maltose as a protectant. In conclusion, fructose and trehalose were most effective as protectants in most strains, and 1× PBS buffer and 0.85% NaCl solution as rehydration solutions were most effective in some strains, respectively.
As fermentation characteristics of Yakju, the soluble solid, reducing sugar and total phenolic compounds was similar concentration under all conditions. In case of the pH, the pH of sample brewed with 100% glutinous rice (GR) was slightly higher than that of the sample brewed with 50% glutinous rice and 50% non-glutinous rice (GR+NGR). On the other hand, the total acid was higher in GR+NGR than in GR. In case of the alcohol, alcohol content of GR was higher than that of GR+NGR, and the alcohol of the single fermented sample was higher than that of the co-fermented sample up to the third day of fermentation. However, final alcohol ranged from 18.6-19.2% under all conditions similarly. In case of the single fermented samples, the viable cell count increased drastically at the beginning of fermentation, and maintained or reduced gradually after the third day. Viable cell count of the co-fermented samples was lower than that of single fermented samples until the 8th day of fermentation, but it was generally higher than that of the single-fermented samples at the end of fermentation. In addition, the final viable cell count of W153 single fermented sample with GR+NGR was the highest, so alcohol content was the highest in this sample. Organic acids were produced in the order of citric acid, succinic acid, malic acid, acetic acid, and lactic acid. Free sugar was detected only glucose as the residual sugar in all samples. Analysis of volatile aromatic compounds found that esters were 13 types, alcohols were 4 types, and sulpur compounds was 1 type. Total ester contents of co-fermented samples were generally higher than those of single-fermented samples. In particular, the content of 2-phenethyl acetate of W153+A159 co-fermented sample with GR+NGR was twice as high as that of W-3 single-fermented sample used as a control, and the 2-phenethyl acetate contents of W153+N373 appeared high under all conditions. In sensory evaluation, the flavor and sweetness scores were the highest in the co-fermentation of W153+A159 with GR+NGR, so overall preference score was also the highest in it.
In this study, optimal air-blast drying conditions of non-Saccharomyces Yakju yeast starters were investigated to make powder form and selected low-temperature tolerant non-Saccharomyces yeasts among these strains were co-fermented with S. cerevisiae to enhance fragrance of Yakju. In addition, the characteristics of Yakju were analyzed according to the amount of glutinous rice added. Consequently, this study would make for the development of Korean fermentation starter industry and high-quality Yakju with various volatile aroma components.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.