• Journal of the Korean Society of Food Science and Nutrition
• /
• v.18 no.4
• /
• pp.435-443
• /
• 1989

The regulation of the synthesis of alcohol-oxidase(E. C. 1. 1. 3. 13) was investigated in the methanol-utilizing yeasts during growth on different carbon sources. For this experiment, Pichia pastoris CBS 2612 and Pichia pastoris CBM 10 were cultured in mineral salt medium by changing its carbon sources. The production of alcohol-oxidase was varied by the carbon sources. For example, alcohol-oxidase was undetectable in all strains submitted to the test in the medium with glucose, but its production was rapidely increased when the carbon source was changed from glucose to methanol after 48hrs of incubation. Moreover, this enzyme was not synthesized during growth on the primary aliphatic alcohols alone(ethanol, propanol, butanol or pentanol) or on the mixed substrates(0.5% methanol+0.5% primary aliphatic alcohols). When cells were grown on the various carbon sources(glucose, xylose, lactose, glycerol, galactose, saccharose, sorbose, lactic acid or acetic acid), The alcohol-oxidase activity was detected a very little amounts. These carbon sources together with methnol yieled far better synthesis of alcohol-oxidase than in case of carbon sources alone. Especially, the alcohol-oxidase activity of the cells grown on sorbose, lactose or lactic acid together with methanol was far better or similar than that of cells grown on methanol alone. The apparent Km values for the methanol of Pichia pastoris CBS 2612 and Pichia pastoris CBM 10 enzymes were 1.92 and 210 mM, respectively. It is also active towards alcohols of shorter alkyl-chain length than $C_7$, insaturated alcohols(allylalcohol, crotyl-alcohol) and secondary alcohols (iso-amylacohol, iso-butylalcohol). The affinity of alcohol-oxidase for this alcohols decreased with the increasing length of the alkyl-chain.

• Korean Journal of Food Science and Technology
• /
• v.51 no.6
• /
• pp.543-550
• /
• 2019

In this study, volatile compounds in 13 aged and 3 commercial rice-distilled soju samples were isolated by headspace solid phase microextraction (HS-SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 85 volatile components including 35 esters, 15 alcohols, 5 ketones, 3 aldehydes, 15 miscellaneous, and 14 unknowns were identified. Esters and alcohols were the largest groups among the quantified volatiles. Differences in volatile compounds among the distilled soju samples and possible sample groupings were examined by principal component analysis of the GC-MS datasets. The first and second principal components (PC1 and PC2, respectively) explained 51.94% of the total variation across the 16 samples. The samples aged in oak containers had higher concentrations of ketones, aldehydes, and miscellaneous compounds. In the positive direction of PC1, oak-aged samples were observed, while, pot-aged samples were observed on the far negative side. Furthermore, samples aged for longer periods, such as 18 months, were observed in the positive direction of PC2.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.4
• /
• pp.521-527
• /
• 2008

Acanthopanacis cortex extracts added Yakju was manufactured and then fermentation and quality characteristics of Yakju were examined. Acanthopanacis cortex extracts added Yakju showed totally similar characteristics with the non-extract added Yakju of control groups. The pH showed almost no change to pH 4.0 after 6 days of fermentation and it was decreased only once in only fermentation time of 3 days. The acidity of Acanthopanacis cortex extracts added group showed no difference to the control group. The sugar obrix and reducing sugar content showed decrease in all two groups in the initial fermentation stage; however, it showed slow decrease as the late fermentation stage. The Acanthopanacis cortex extracts added Yakju showed less alcohol content than the control group in the initial fermentation stage. However, after 6 days of fermentation, the Acanthopanacis cortex extracts added Yakju showed more alcohol contents and constant increase till the final fermentation day. The pH, acidity, reducing sugar and alcohol content showed rapid changes between fermentation days 0 through 3. Therefore, it means that the Acanthopanacis cortex extracts added Yakju fermentation actively takes place between the days 0 through 3. Organic acids detected in Yakju were acetic, lactic, oxalic, malic and succinic acids. The acetic acid was the highest among the total acid contents. Eleutheroside E and chlorogenic acid, known as the effective components of Acanthopanacis cortex, showed stable status without changes in component content till stage two fermentation. The contents of eleutheroside E and chlorogenic acid were $7.61\pm0.39{\mu}g/mL$ and $3.63\pm0.18{\mu}g/mL$ on the final fermentation day, respectively. The fusel oil was slightly detected in both groups with values of $0.08\pm0.001{\sim}0.86\pm0.03mg%$ in n-propyl alcohol, isobutyl alcohol and isoamyl alcohol content. The Acanthopanacis cortex extracts added group was similar to the control group in the overall sensory test.

• Journal of the East Asian Society of Dietary Life
• /
• v.27 no.2
• /
• pp.159-167
• /
• 2017

In this study, quality characteristics of yakju fermented with byeo-nuruk prepared using rice, wheat, and water were investigated. Five different mixture ratios were considered for byeo-nuruk preparation. A comparative analysis of commercial yakju and byeo-nuruk yakju was also performed. The results showed no significant differences in pH, total acidity, and total soluble solids of byeo-nuruk yakju immediately following fermentation. The byeo-nuruk yakju alcohol content increased with increasing wheat proportion. Lactic and succinic acid were the major organic acids of byeo-nuruk yakju, and the major volatile components were isoamyl alcohol and linalool. Yakju prepared using material D had the highest volatile component content and high preference evaluation scores for taste and overall acceptability. Compared to commercial yakju, byeo-nuruk yakju had less total acidity, soluble solids, and volatile acids, whereas its pH level and amino acid content were higher. No significant differences were observed between commercial yakju and byeo-nuruk yakju in terms of sensory evaluation.

• Analytical Science and Technology
• /
• v.17 no.1
• /
• pp.23-28
• /
• 2004

Trace amount of uranyl (II) has been determined spectrophotometrically by measuring the optical density of the light blue yellowish coloured solutions formed by reaction between the metal ion and nicotinohydroxamic acid (NHx) in presence of different secondary ligands in strong isoamyl alcohol alkaline medium. The absorption maxima for both aqueous and extracted systems measured at their respective optimum pH were found to be 360 and 559 nm (DETA), 375 and 358 nm (EDA), 369 and 362 nm (piperidine), 354 and 341 nm (pyridine) and 363 and 336 nm (3 piperidine), 354 and 341 nm (pyridine) and 363 and 336 nm (3 - picoline), respectively at which Beer's law was obeyed. Effect of pH, reagent concentration, order of addition of reagent, time, temperature and solvent media on the absorption spectra have also been studied. Among the different systems studied, the shortest concentration range of uranyl(II) adhering to Beer's Law was 2.4 - 10.5 ppm observed for $UO_2(II)$ - NHx - DETA system in aqueous medium and also for iso amyl alcohol(IAA) extracted $UO_2$ - NHx - pyridine system was 2.4 - 7.8.

• The Korean Journal of Food And Nutrition
• /
• v.12 no.4
• /
• pp.421-426
• /
• 1999

The major flavor compounds of Takju mash which was brewed with a modified Nuruk made by inocu-lation and cultivation of Rhizopus japonicus T2, Aspergillus oryzae L2 and Hansenula sp. BC26 isolated from Nuruk, were analyzed, as compared with those with current fermenting agents such as commerical Nur-uk and rice koji of Aspergillus kawachii. The contents of isoamyl alcohol isobutyl alcohol and ethyl acet-ate which were known as aroma compounds in Takju were much higher in mash of modified Nuruk than in that of commercial Nuruk or ricd koji. The major organic acids were lactic fumalic and succinic acid in mash of modified and lactic and acetic acid in mash of commercial Nuruk and citric lactic and suc-cinic acid in mash of rice koji. The contents of total organic acids were 5,146mg/L, 1,706mg/L and 1, 388 mg/L in mash of commercial Nuruk rice koji and modified Nuruk respectively. The major free amino acids were glutamic acid alanine proline and histidine in mash of modified Nuruk and glutamic acid proline leucine and histidine in mash of commercial Nuruk and arginine proline and glutamic acid in mash of rice koji. The contents of total free amino acids were 14,090mg/L 12,202mg/L and 7,152 mg/L in mash of modified Nuruk commercial Nurcuk and rice koji respectively. Therefore it seemed that the Takju mash of modified Nuruk was better than that of commercial Nuruk or rice koji.

• Microbiology and Biotechnology Letters
• /
• v.14 no.5
• /
• pp.371-376
• /
• 1986

This study to elucidate concentrations of impurities such as methanol and fusel oil formed during fermentation process among the different materials and has been applied technical seperation for processing improvement by continuous distillation of super-allospas type. Methanol was formed high concentrations of cutting dried sweet potato and tapioca in order among the different materials during fermentation process. n-Propanol oil was formed high concentration of rice, cutting dried sweet potato, corn, naked barley and tapioca in order among the those materials. I-Buthanol showed high concentration of tapioca, corn, rice, cutting dried sweet potato and naked barley in order and isoamyl-alcohol showed high concentration of tapioca, rice, cutting dried sweet potato, corn and naked barley in order. Using the continuous distillation of super-allospas type, the following are collection ratios of n-propanol, iso-butanol, n-butanol and iso-amylalcohol: 37.9％, 28.6％, 37.4％, and 56.1％ when 78.25％ (v/v), 68.54％ (viv), 50.0％ (viv), and 50.0％ (v/v) alcohol are used, respectively. Fusel oil and bad alcohol put into the recovery column and then seperated directly by side cut of fusel oil partially from plate of tower bottom after concentration again. Extra impurities seperated by fusel oil seperator when 20 ％ (v/v) alcohol adjusted with water.

• Food Engineering Progress
• /
• v.13 no.4
• /
• pp.302-307
• /
• 2009

In this study, four Korean black raspberry wines were developed from different regions in Korea; Gochang (G), Heongsung (H), Jeongup (J), and Sungchang (S). Their flavor profiles were determined using a combination of volatile analysis and sensory evaluation. From the volatile analysis of the developed wines, 8 acids, 17 alcohols, 12 esters, 9 terpenes, 3 aldehydes and ketones, and 4 miscellaneous compounds were identified. Preferences of appearance, aroma, full-body, and overall acceptability in the developed wines were determined using 9-point hedonic scale by 43 panelists, compared with one commercial black raspberry wine (Sunw). The sweetness, sourness, astringency levels were also evaluated using 9-point just-about-right (JAR) scale. The mean overall acceptability score of Sunw (5.58) was the highest among the tested wines, followed by G (4.81), S (4.44), H (4.41), and J (4.13) (p<0.05). Sweetness levels in the developed wines were overall lower than JAR level, while sourness and astringency levels were overall higher than JAR level.

• Korean Journal of Food Science and Technology
• /
• v.53 no.5
• /
• pp.640-647
• /
• 2021

In this study, we analyzed three rice pre-treatment methods for the preparation of mit-sool (first mashing), with godubap (steamed rice), beombeok (undercooked porridge), and juk (porridge). The results can provide basic data for the development of takju with improved quality. In terms of the base alcohol, godubap produced the highest amount of alcohol (8.1%) after two days, followed by beombeok and juk. After two days of fermentation, soluble solids were measured at 15.3, 15.1, and 1.4°Brix in beombeok, juk, and godubap, respectively, The glucose content of godubap did not change significantly; however, the maltose content increased. In beombeok, maltose decreased from 16.48 mg/mL on the initial day 0 to 1.27 mg/mL on day 9. In juk, glucose and maltose increased from 14.05 and 11.49 mg/mL on day 0 to 31.39 and 42.53 mg/mL on day 2, respectively. Succinic acid levels increased in the godubap and beombeok mit-sool. However, succinic acid was not detected in godubap and juk during the initial stage of fermentation, and lactic acid was not detected in beombeok mit-sool. During the fermentation stage of deot-sool (second mashing), the highest alcohol content of takju made with godubap alcohol was 18.0% and the lowest alcohol content was 15.1% in beombeok on day 9. The total acidity was as high as 0.54% for beombeok, 0.41% for juk, and 0.39% for godubap. In the flavor analysis, ethyl caprate and ethyl caprylate, which were high on day 0 in godubap, decreased upon the completion of fermentation on day 9. Banana-flavored isoamyl alcohol content increased. For juk, ethyl caprate and ethyl caprylate, which were high on day 0, decreased on day 9. Flavor components, such as ethyl palmitate and ethyl linoleate were increased.

• Korean Journal of Food Science and Technology
• /
• v.45 no.2
• /
• pp.142-147
• /
• 2013

This study was conducted to evaluate and compare new beer (NB) with market beers, e.g., New castle brown ale (NC), Victoria bitter (VB), and Coopers pale ale (CP) using physicochemical parameters. In addition, pattern recognition analyses were carried out using an electronic nose based on mass spectrometry (MS-E nose) and an electronic tongue (E-tongue) for differentiation of the different types of beer. The measured alcohol content of NB was 4.37%. NB was not significantly different compared with other types of beer with regard to bitterness unit, color, and polyphenol content (p<0.05). On the basis of the flavor pattern determined by the MS-E nose, NB was separated by DF1 (first score from discriminant function analysis), while NC, VB, and CP were located in the same group. The result of the E-tongue showed that the different samples could be clearly discriminated; NB was less sour. It was suggested that the discriminant function analysis (DFA) given by the MS-E nose and E-tongue could be used for evaluations during new product development. Furthermore, because of its simplicity, it might be possible to use the validated method for the evaluation of beer.