• Applied Biological Chemistry
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• v.10
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• pp.69-100
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• 1968

1. In order to investigate on the microflora and enzyme activity of mold wheat 'Nuruk' , the major source of microorganisms for the brewing of Takju (a Korean Sake), two samples of Nuruk, one prepared at the College of Agriculture, Chung Nam University (S) and the other perchased at a market (T), were taken for the study. The molds, aerobic bacteria, lactic acid bacteria, and yeasts were examined and counted. The yeasts were classified by the treatment with TTC (2, 3, 5 triphenyltetrazolium chloride) agar that yields a varied shade of color. The amylase and protease activities of Nuruk were measured. The results were as the followings. a) In the Nuruk S found were: Aspergillus oryzae group, $204{\times}10^5$; Black Aspergilli, $163{\times}10^5$; Rhizogus, $20{\times}10^5$; Penicillia, $134{\times}10^5$; Areobic bacteria, $9{\times}10^6-2{\times}10^7$; Lactic acid bacteria, $3{\times}10^4$ In the Nuruk T found were: Aspergillus oryzae group, $836{\times}10^5$; Black Aspergilli, $286{\times}10^5$; Rhizopus, $623{\times}10^5$; Penicillia, $264{\times}10^5$; Aerobic bacteria, $5{\times}10^6-9{\times}10^6$; Lactic acid bacteria, $3{\times}10^4$ b) Eighty to ninety percent of the aerobic bacteria in Nuruk S appeared to belong to Bacillus subtilis while about 70% of those in Nuruk T seemed to be spherical bacteria. In both Nuruks about 80% of lactic acid bacteria were observed as spherical ones. c) The population of yeasts in 1g. of Nuruk S was about $6{\times}10^5$, 56.5% of which were TTC pink yeasts, 16% of which were TTC red pink yeasts, 8% of which were TTC red yeasts, 19.5% of which were TTC white yeasts. In Nuruk T(1g) the number of yeasts accounted for $14{\times}10^4$ and constituted of 42% TTC pink. 21% TTC red pink 28% TTC red and 9% TTC white. d) The enzyme activity of 1g Nuruk S was: Liquefying type Amylase, $D^{40}/_{30},=256$ W.V. Saccharifying type Amylase, 43.32 A.U. Acid protease, 181 C.F.U. Alkaline protease, 240C.F.U. The enzyme activity of 1g Nuruk T was: Liquefying type Amylase $D^{40}/_{30},=32$ W.V. Saccharifying type amylase $^{30}34.92$ A.U. Acid protease, 138 C.F.U. Alkaline protease 31 C.F.U. 2. During the fermentation of 'Takju' employing the Nuruks S and T the microflora and enzyme activity throughout the brewing were observed in 12 hour intervals. TTC pink and red yeasts considered to be the major yeasts were isolated and cultured. The strains ($1{\times}10^6/ml$) were added to the mashes S and T in which pH was adjusted to 4.2 and the change of microflora was examined during the fermentation. The results were: a) The molds disappeared from each sample plot since 2 to 3 days after mashing while the population of aerobic bacteria was found to be $10{\times}10^7-35{\times}10^7/ml$ inS plots and $8.2{\times}10^7-12{\times}10^7$ in plots. Among them the coccus propagated substantially until some 30 hours elasped in the S and T plots treated with lactic acid but decreased abruptly thereafter. In the plots of SP. SR. TP. and TR the coccus had not appeared from the beginning while the bacillus showed up and down changes in number and diminished by 1/5-1/10 the original at the end stage. b) The lactic acid bacteria observed in the S plot were about $7.4{\times}10^7$ in number per ml of the mash in 24 hours and increased up to around $2{\times}10^8$ until 3-4 days since. After this period the population decreased rapidly and reached about $4{\times}10^5$ at the end, In the plot T the lactic acid becteria found were about $3{\times}10^8$ at the period of 24 fours, about $3{\times}10$ in 3 days and about $2{\times}10^5$ at the end in number. In the plots SP. SR. TP, and TR the lactic acid bacteria observed were as less as $4{\times}10^5$ at the stage of 24 hours and after this period the organisms either remained unchanged in population or ceased to exist. c) The maiority of lactic acid bacteria found in each mash were spherical and the change in number displayed a tendency in accordance with the amount of lactic acid and alcohol produced in the mash. d) The yeasts had showed a marked propagation since the period of 24 hours when the number was about $2{\times}10^8$ ㎖ mash in the plot S. $4{\times}10^8$ in 48 hours and $5-7{\times}10^8$ in the end period were observed. In the plot T the number was $4{\times}10^8$ in 24 hours and thereafter changed up and down maintaining $2-5{\times}10^8$ in the range. e) Over 90% of the yeasts found in the mashes of S and T plots were TTC pink type while both TTC red pink and TTC red types held range of $2{\times}10-3{\times}10^7$ throughout the entire fermentation. f) The population of TTC pink yeasts in the plot SP was as $5{\times}10^8$ much as that is, twice of that of S plot at the period of 24 hours. The predominance in number continued until the middle and later stages but the order of number became about the same at the end. g) Total number of the yeasts observed in the plot SR showed little difference from that of the plot SP. The TTC red yeasts added appeared considerably in the early stage but days after the change in number was about the same as that of the plot S. In the plot TR the population of TTC red yeasts was predominant over the T plot in the early stage which there was no difference between two plots there after. For this reason even in the plot w hers TTC red yeasts were added TTC pink yeasts were predominant. TTC red yeasts observed in the present experiment showed continuing growth until the later stage but the rate was low. h) In the plot TP TTC pink yeasts were found to be about $5{\times}10^8$ in number at the period of 2 days and inclined to decrease thereafter. Compared with the plot T the number of TTC pink yeasts in the plot TP was predominant until the middle stage but became at the later stage. i) The productivity of alcohol in the mash was measured. The plot where TTC pink yeasts were added showed somewhat better yield in the earely stage but at and after the middle stage the difference between the yeast-added and the intact mashes was not recognizable. And the production of alcohol was not proportional to the total number of yeasts present. j) Activity of the liquefying amylase was the highest until 12 hours after mashing, somewhat lowered once after that, and again increased around 36-48 hours after mashing. Then the activity had decreased continuously. Activity of saccharifying amylase also decreased at the period of 24 hours and then increased until 48 hours when it reached the maximum. Since, the activity had gradually decreased until 72 hours and rapidly so did thereafter. k) Activity of alkaline protease during the fermentation of mash showed a tendency to decrease continusously although somewhat irregular. Activity of acid protease increased until hours at the maximum, then decreased rapidly, and again increased, the vigor of acid protease showed better shape than that of alkaline protease throughout. 3. TTC pink yeasts that were predominant in number, two strains of TTC red pink yeasts that appeared throughout the brewing, and TTC red yeasts were identified and the physiological characters examined. The results were as described below. a) TTC pinkyeasts (B-50P) and two strains of TTC red pink yeasts (B-54 RP & B-60 RP) w ere identified as the type of Saccharomyces cerevisiae and TTC pink red yeasts CB-53 R) were as the type of Hansenula subpelliculosa. b) The fermentability of four strains above mentioned were measured as follows. Two strains of TTC red pink yeasts were the highest, TTC pink yeasts were the lowest in the fermantability. The former three strains were active in the early stage of fermentation and found to be suitable for manufacturing 'Takju' TTC red yeasts were found to play an important role in Takju brewing due to its strong ability to produce esters although its fermentability was low. c) The tolerance against nitrous acid of strains of yeast was marked. That against lactic acid was only 3% in Koji extract, and TTC red yeasts showed somewhat stronger resistance. The tolerance against alcohol of TTC pink and red pink yeasts in the Hayduck solution was 7% while that in the malt extract was 13%. However, that of TTC red yeasts was much weaker than others. Liguefying activity of gelatin by those four strains of yeast was not recognized even in 40 days. 4. Fermentability during Takju brewing was shown in the first two days as much as 70-80% of total fermentation and around 90% of fermentation proceeded in 3-4 days. The main fermentation appeared to be completed during :his period. Productivity of alcohol during Takju brewing was found to be apporximately 65% of the total amount of starch put in mashing. 5. The reason that Saccharomyces coreanuss found be Saito in the mash of Takju was not detected in the present experiment is considered due to the facts that Aspergillus oryzae has been inoculated in the mold wheat (Nuruk) since around 1930 and also that Koji has been used in Takju brewing, consequently causing they complete change in microflora in the Takju brewing. This consideration will be supported by the fact that the original flavor and taste have now been remarkably changed.

• Journal of Life Science
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• v.21 no.4
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• pp.509-514
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• 2011

Maloactic fermentation (MLF) occurs after completion of alcoholic fermentation and is mediated by lactic acid bacteria (LAB), mainly Oenococcus oeni. Kiwi wine more than commercial grape wine has the problem of high acidity. Therefore, we investigated the optimal MLF conditions for regulating strong acidity and improving the quality properties of wine fermented with Kiwi fruit cultivated in Korea. For alcohol fermentation, industrial wine yeast Saccharomyces cerevisiae KCCM 12650 strains and LAB, known as MLF strains, were used to alleviate wine acidity. First, the various experimental conditions of Kiwi fruit, initial pH (2.5, 3.5, 4.5), fermenting temperature (20, 25, $30^{\circ}C$), and sugar contents (24 $^{\circ}Brix$), were adjusted, and after the fermentation period, we measured the acidity, pH, and the change in organic acid content by the AOAC method and HPLC analysis. The alcohol content of fermented Kiwi wine was 12.75%. Further, total acidity and pH of Kiwi wine were 0.78% and 3.5, respectively. Total sugar and total polyphenol contents of Kiwi wine were 38.72 mg/ml and 60.18 mg/ml, respectively. With regard to organic acid content, the control contained 0.63 mg/ml of oxalic acid, 2.99 mg/ml of malic acid, and 0.71 mg/ml of lactic acid, whereas MLF wine contained 0.69 mg/ml of oxalic acid, 0.06 mg/ml of malic acid, and 3.12 mg/ml of lactic acid. Kiwi wine had lower malic acid values and total acidity than control after MLF processing. In MLF, the optimum initial pH value and fermentation temperature were 3.5 and $25^{\circ}C$, respectively. Therefore, these studies suggest that establishment of optimal MLF conditions could improve the properties of Kiwi wine manufactured in Korea.

• Applied Biological Chemistry
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• v.11
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• pp.1-27
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• 1969

More than thirty kinds of sea food pickles have been eaten in Korea. Out of these salted yellow tail pickle, salted clam pickle, salted oyster pickle, and salted cuttlefish pickle were employed for the analysis of their components, identification of main fermenting microbes, and determination of enzyme characteristics concerned. Also studied was the effect of enzymic action of microbes, which are concerned with the fermenting of pickles, on the production of flavorous 5'-mononucleotides and amino acids. The results are summarized as follows: 1. Microflora observed in the pickles are: (a) Total count of viable cells after 1-2 months of pickling was found to be $10^7$ and that after 6 months decreased to $10^4$. (b) Microbial occurence in the early stage of pickling was observed to be 10-20% Micrococcus spp., 10-20% Brevibacterium spp., 0-30% Sarcina spp., 20-30% Leuconostoc spp., ca 30% Bacillus spp., 0-10% Pseudomonas spp., 0-10% Flavobacterium spp., and 0-20% yeast. (c) Following the early stage of pickling, mainly halophilic bacteria such as Bacillus subtilis, Leuconostoc mesenteroides, Pediococcus halophilus and Sarcina litoralis, were found to exhibit an effect on the fermentation of pickle and their enzyme activities were in direct concern in fermentation of pickles. (d) Among the bacteria participating in the fermentation, Sarcina litoralis 8-14 and 8-16 strains were in need of high nutritional requirement and the former was grown only in the presence of purine, pyrimidine and cystine and the latter purine, pyrimidine and glutamic acid. 2. Enzyme characteristics studied in relation to the raw materials and the concerned microbes isolated are as follows: (a) A small amount of protease was found in the raw materials and 30-60% decrease in protease activity was demonstrated at 7% salt concentration. (b) Protease activity of halophilic bacteria, Bacillus subtilis 7-6, 11-1, 3-6 and 9-4 strains, in the complete media decreased by 10-30% at the 7% salt concentration and that of Sarcina litoralis 8-14 and 8-16 strains decreased by 10-20%. (c) Proteins in the raw materials were found to be hydrolyzed to yield free amino acids by protease in the fermenting microbes. (d) No accumulation of flavorous 5'-mononucleotides was demonstrated because RNA-depolymerase in the raw materials and the pickles tended to decompose RNA into nucleoside and phosphoric acid. (e) The enzyme produced in Bacillus subtilis 3-6 strain isolated from the salted clam pickles, was ascertained to be 5'-phosphodiesterase because of its ability to decompose RNA and thus accumulating 5'-mononucleotide. (f) It was demonstrated that the activity of phosphodiesterase in Bacillus subtilis 3-6 strain was enhanced by some components in the corn steep liquor and salted clam pickle. The enzyme activity was found to decrease by 10-30% and 40-60% at the salt concentration of 10% and 20%, respectively. 3. Quantitative data for free amino acids in the pickles are as follows: (a) Amounts of acidic amino acids such as glutamic and aspartic acids in salted clam pickle, were observed to be 2-10 times other pickles and it is considered that the abundance in these amino acids may contribute significantly to the specific flavor of this food. (b) Large amounts of basic amino acids such as arginine and histidine were found to occur in salted yellow tail pickle. (c) It is much interesting that in the salted cuttlefish pickle the contents of sulfur-containing amino acids were exceedingly high compared with those of others: cystine was found to be 17-130 times and methionine, 7-19 times. (d) In the salted oyster pickle a high content of some essential amino acids such as lysine, threonine, isoleucine and leucine, was demonstrated and a specific flavor of the pickle was ascribed to the sweet amino acids. Contents of alanine and glycine in the salted oyster pickle were 4 and 3-14 times as much as those of the others respectively. 4. Analytical data for 5'-mononucleotides in the pickles are as follows: (a) 5'-Adenylic acid and 3'-adenylic acid were found in large amounts in the salted yellow tail pickle and 5'-inosinic acid in lesser amount. (b) 5'-Adenylic acid, especially 3'-adenylic acid predominated in amount in the salted oyster pickle over that in the other pickles. (c) The salted cuttlefish pickle was found to contain only 5'-adenylic acid and 3'-adenylic acid. It has become evident from the above fact that clam and the invertebrate lack of adenylic deaminase and contain high content of adenylic acid. Thus, they were demonstrated to be the AMP-type. (d) 5'-Inosinic acid was contained in the salted yellow tail pickle in a significant concentration, and it might be considered to be IMP-type. 5. Comparative data for flavor with regard to the flavorous amino acids and the contents of 5'-mononucleotides are: (a) A specific flavor of salted yellow tail pickle was ascribed to the abundance in glutamic acid and aspartic acid, and to the existence of a small amount of flavorous 5'-inosinic acid. The combined effect of these components was belived to exhibit a synergistic action in producing a specific fiavor to the pickle. (b) A specific flavor of salted clam pickle has been demonstrated to be attributable to the richness in glutamic acid and aspartic acid rather than to that of 5'-mononucleotides.

• Korean Journal of Agricultural Science
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• v.8 no.2
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• pp.171-178
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• 1981

In order to develope the suitable processing method of new alcohol fermented milk beverage, the lactic acid bacteria and the yeast were inoculated to various level of saccharide added milk. And the change of component and alcohol concentration in beverage were analysed and tested. The results obtained were summarized as follows: 1. By skim milk media was fermented by the 5 strains of lactic acid bacteria for 24 hours, most suitable acidity was appeared in the Str. lactis fermented beverage as 0.83% and the amino nitrogen contents was not much changed as 0.2mg/ml. 2. By the skim milk was added with 5% glucose, lactose and sucrose respectively and fermented by the Str. lactis and Cruyveromyces fragilis, the acidity and amino nitrogen contents in beverage were not changed significantly, but alcohol concentration was increased from 2.5% to 3.58%. 3. By the 5% to 15% sucrose added skim milk media was fermented by Cruyveromyces fragilis and Saccharomyces cerevisiae, the amino nitrogen concentration was not so much changed by increasing sucrose contents. And the alcohol concentration was increased from 2.12% to 8.15% by Cruyveromyces fragilis fermentation and from 0% to 7.45% by S.accharomyces cerevisiae fermentation. 4. Sensory evaluation was better in the Cruyveromyces fragilis fermented beverage than Saccharomyces cerevisiae fermented beverage. 5. The contents of moisture, crude protein, ash and the concentrate of alcohol of Str. lactis and Cruyveromyces fragilis fermented skim milk beverage were much similar to koumis.

• KSBB Journal
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• v.22 no.5
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• pp.305-312
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• 2007

It is crucial to develop a miniaturized cultivation method for large and rapid screening of high-yielding mutants of monacolin-K, a powerful anti-hypercholesterolemic secondary metabolite biosynthesized by the fungal cells of Monascus ruber. In order to investigate as many strains as possible in a short time, a miniaturized fermentation method especially suitable for the cultivation of the filamentous Monascus mutants was developed using $50m{\ell}$ culture-tube ($7m{\ell}$ of working volume) instead of the traditional $250m{\ell}$ flask ($50m{\ell}$ of working volume). Generally, in filamentous fungal cell fermentations, morphologies in growth and production cultures should be maintained as thick filamentous and compact-pelleted (usually less than 1 mm in diameter) forms, respectively, for enhanced production of secondary metabolites in final production cultures. In this study, we intended to induce the respective optimal morphologies in the miniaturized culture system for the purpose of rapid screening of overproducers. Miniaturized growth culture system was successfully developed due to the mass production of spores in the statistically optimized solid medium. When large amounts of spores were inoculated into the growth cultures, and brown rice flour (20 g/L) was also supplemented to the growth medium, dense filamentous morphologies were successfully induced in the growth cultures performed with the 50 ml culture tubes. It was implied that the amounts of spores inoculated into the growth tube-cultures and the growth medium components should be the key factors for the induction of the filamentous forms in the growth fermentations. Furthermore, in order to statistically optimize production medium, multiple experiments based on Plackett-Burman design and response surface method (RSM) were carried out, resulting in more than 2 fold enhanced production of monacolin-K in the final production cultures with the optimized production medium. Notably, under the production culture conditions with the statistically optimized medium, optimal pellet sizes below 1 mm in diameter were reproducibly induced, in contrast to the thick and viscous filamentous morphologies observed in the previous production cultures.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.1
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• pp.76-82
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• 2009

Wheat is the most widely cultivated cereal and an important source of dietary protein worldwide. Wheat allergy, defined as an adverse immunologic reaction to wheat, encompasses a broad spectrum of disorders with different pathomechanisms and clinical manifestation. The Nuruk, a traditional Korean Koji for brewing, was made with wheat flour and fermenting microbes such as bacteria, yeast and mold. The strains grown on Nuruk secrete various enzymes as amylase and protease. By the activation of such enzymes, starch and proteins in Nuruk are hydrolyzed to sugar and amino acid. Therefore, it is supposed to reduce allergic proteins in wheat. To study quality properties and degradation degree of allergenicity in Nuruk by fermentation, we investigated the changes of general ingredients and allergenicity in Nuruk during fermentation. Moisture contents was decreased from 24.2% to 13.6% during fermentation. Crude lipid and protein contents were gradually increased during fermentation. After 15 days of fermentation, reducing sugar and total sugar contents were reached its maximum level, and they were 27.45% and 39.00%, respectively. Acid and neutral protease activity were significantly increased during fermentation, but alkaline protease activity was not detected. ${\alpha}$-amylase activity was gradually increased and showed maximum level about 2,833.00 U/g after 15 days of fermentation. Glucoamylase activity was the highest level about 497.9 U/g after 10 days of fermentation. The increase of these proteolytic and saccharogenic enzyme activities will provide efficient condition for production of rice wine. Also, protein fractions were isolated from Nuruk, and degradation of these proteins during fermentation were confirmed by SDS-PAGE. IgE immunoblotting using patient's sera with wheat allergy was performed to confirm allergenic protein in Nuruk. These results as fermentation of Nuruk will provide a useful tool for developing safer wheat products to prevent wheat allergy.

• Journal of Life Science
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• v.26 no.1
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• pp.17-22
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• 2016

Ethanol is a very valuable material, however, it is also a source of stress, as the accumulation of ethanol in a medium inhibits cell viability and decreases productivity of the target product. Therefore, the ethanol tolerance of yeast, which is closely related to ethanol productivity, is an important factor in industrial ethanol production. In this study, the YDJ1 and PEP5 genes were selected as target genes for elucidating ethanol-tolerant mechanisms by analyzing the expression regulation of these genes. The pA-YDJ1 and pA-PEP5 plasmids containing YDJ1 and PEP5 genes under an ADH1 promoter, respectively, were constructed and transformed into BY4742 (host strain), BY4742△ydj1, and BY4742△pep5 strains. The ethanol tolerance in the BY4742△ydj1/ pA-YDJ1 and BY4742△pep5/pA-PEP5 transformants was restored by overexpression of the YDJ1 and PEP5 genes to the host strain level. The YDJ1 and PEP5 genes were also introduced into the double gene disruptant (BY4742△ydj1△pep5) to investigate the expression regulation of the YDJ1 and PEP5 genes. The simultaneous overexpression of the YDJ1 and PEP5 genes restored ethanol tolerance to the 90% level of the BY4742 strain under 8% ethanol stress. The YDJ1 gene induced more overexpression of the PEP5 gene in the BY4742△ydj1 △pep5/pA-YDJ1, pA-PEP5 strain, suggesting that the YDJ1 gene partially regulates the expression of the PEP5 gene as an upstream regulator.

• Food Science and Preservation
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• v.21 no.5
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• pp.627-635
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• 2014

We investigated the changes in the quality characteristics of Doenjang with low salt contents (6, 8, 10, and 12%) and 10% garlic. The Doenjang was analyzed at an interval of a week during its fermentation for six weeks, at room temperature. Its L color gradually decreased, but its a and b colors did not change significantly. Its salinity increased by about 1% after six weeks. In contrast, immediately after its preparation, its pH was gradually decreased and its acidity was increased for the fermentation. The reducing sugar was significantly increased from 1.34~1.88 g/100 g immediately after its preparation to 7.25~9.13 g/100 g after six weeks, which was higher as the salt concentration decreased. The amino-type nitrogen doubled from 100~130 mg% at 0 week to 210~290 mg% at six weeks, which were lower with the higher salt concentrations. The growth curve of the Bacillus fermentation strains of Doenjang increased to two weeks but gradually decreased since, and the growth of the Bacillus was favorable for up to two weeks in the Doenjang with 10% and 12% salt added. Otherwise, the yeast was reduced rapidly during the early fermentation of the Doenjang, and slightly changed after three weeks of fermentation. The results of this study showed that the reducing sugar and amino-type nitrogen contents of the low-salt garlic Doenjang were higher with the lower salt dose, and the physicochemical quality of the 6%-salt Doenjang was not significantly affected. Thus, we suggest that low-salt Doenjang can be manufactured with the addition of 6% salt and 10% garlic.

• The Korean Journal of Food And Nutrition
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• v.28 no.4
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• pp.666-675
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• 2015

This study was carried out to develop rose sparkling wine with reed root. To make the base wine with reed root extracts, we first blended wild grape wine with reed root extracts (1:9 v/v) and fermented the mixture for 14 days at $20^{\circ}C$. The pH of the control and the rose base wine with reed root extract (RWE) decreased with increasing fermentation time, but acidity showed the opposite behavior. The control and RWE had $7.33^{\circ}Brix$, and $6.90^{\circ}Brix$, respectively at 14 days, with higher sugar content in the control than in RWE. The alcohol content increased as the fermentation progressed and was higher in RWE than in the control at 14.20% and, 13.83%, respectively. Regarding the color, the lightness decreased as the fermentation progressed. The total polyphenol contents of the control and RWE were 29.19 mg/100 mL and, 34.97 mg/100 mL. The flavonoids decreased as the fermentation progressed. The ABTS radical scavenging activity of the control and RWE were 44.26% and, 64.37% while the DPPH radical scavenging activity showed similar results in the control and RWE. In the second test, we added RWE to base wine, because yeast rearing was inhibited at 14% alcohol content. We made sparkling rose wine with 4 strains and fermented the wine for 8 days at $20^{\circ}C$. The pH of the samples decreased with increasing fermentation time, but the acidity showed the opposite behavior. The $^{\circ}Brix$ decreased and the alcohol content increased with increasing fermentation time. The pressure in sample A was $4.30kgf/cm^2$ at 8 days which was the highest in the samples. In the sensory evaluation, the color, flavor, softness and overall acceptability of the control was higher than the other samples. In conclusion, Saccharomyces cerevisiae Vitilevure Quartz was overall the most suitable rose sparkling wine.

• Applied Biological Chemistry
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• v.18 no.1
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• pp.16-22
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• 1975

This experiment was carried out to investigate the physiological characteristics of two original yeasts, 5-Y-5 and 6-Y-6, which selected from 24 Takju yeasts and three mutants, 30-24,30-81 and 40-27. induced from two original yeasts by the irradiation of UV light. The results were summarized as follows. 1) Alcohol tolerances of three mutants were decreased in some degree as compared with those of original yeasts. 2) Tolerances of lactic and citric acids of acid producing mutant 30-81, was increased than those of original yeasts. 3) In the case of using ammonium sulfate as a nitrogen source, two original yeasts and three mutants required Ca-pantothenate as a essential growth factor and four strains of yeasts except the mutant, 30-81, required biotin as a stimulated growth factor, When asparagine was used as a nitrogen source, two original yeasts and three mutants showed the same as above result but the stimulated effect of biotin was far less. 4) Propagation powers of the mutants were weaken than those of original yeasts, particular that of acid producing mutant, 30-81, was the weakest in the three mutants. 5) The optimum temperature for fermentation of original yeasts were $30^{\circ}C\;to\;35^{\circ}C$ but three mutants were $25^{\circ}C\;to\;30^{\circ}C$. 6) The optimum pH for fermentation of original yeasts were pH 5 to 6, and there is no appreciable difference between original yeasts and three mutants. The fermentation power of mutant,30-81, was decreased more rapidly than those of other mutants according to approach neutral. Three mutants were more sensible to heat than original yeasts. 7) Two original yeasts and three mutants were inhibited more over 20 percent of sugar for fermentation and three mutants were more sensible to sugar concentration than original yeasts.