• Food Science and Biotechnology
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• v.14 no.5
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• pp.576-580
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• 2005

Ten yeast strains affecting doenjang flavor were isolated from soybean fermented foods (traditional meju and doenjang), among which Zygosaccharomyces sp. Y-2-5, showing excellent growth, glucose consumption, pH, and flavor production, was selected. Higher alcohols produced by Zygosaccharomyces sp. Y-2-5 related to flavor were 2-propanol, 1-propanol, 2-methyl-1-propanol, 1-butanol, and 3.3-dimethyl-2-butanol. Optimal culture conditions for Zygosaccharomyces sp. Y-2-5 were 10% (w/v) NaCl, pH 4.0, 3.0% (w/v) glucose concentration, and inoculation time day 0 or 15 doenjang fermentation.

• Korean journal of food and cookery science
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• v.31 no.3
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• pp.296-303
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• 2015

We investigate black raspberry (Rubus occidentalis) wine made using traditional yeast (Saccharomyces cerevisiae A8, B6, GBY2, GBY3) and S. cerevisiae Fermivin (FM), which is widely used in wine manufacturing, and analyze the biogenic amine content and the volatile flavor compounds. Black raspberries were separately inoculated with yeast up to $1{\times}10^9CFU/kg$, followed by incubation at $25^{\circ}C$ for 7 days. FM produced the highest alcohol content, however the final fermentation characteristics of the wine made using four different yeasts were similar. S. cerevisiae A8 had a large biogenic amine (BA) content, specifically tryptamine, thus we excluded this yeast from fermentation. S. cerevisiae GBY3 was selected for black raspberry wine fermentation as a result of sensory evaluation. The volatile flavor compounds of two wines (S. cerevisiae GBY3 and FM) were analyzed by gas chromatography and mass spectrometry. 37 compounds in the samples were separated, and several ester compounds were identified in greater amounts in the wine made with S. cerevisiae GBY3 than in the wine made with FM. A greater amount of the major compound, ethyl benzoate, giving the sweet and fruity flavor, was identified in wine made with S. cerevisiae GBY3 than in the wine made with FM. In conclusion, S. cerevisiae GBY3 was confirmed to produce no major BAs and a better flavored wine. These results give new leads in the production of high quality wine.

• The Korean Journal of Food And Nutrition
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• v.8 no.4
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• pp.280-288
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• 1995

Because yeast is rich in vitamins, nucleotides and essential amino acids, it has been used as a nutrient and dietary supplements. Particularly yeast extract functions as a seasoning, flavor enhancer in meats. In this study, naturally occurring insoluble components during yeast extract process by autolysis were microanalyses by using SEM, XRD, HPLC, GC, FT-lR and DSC. On the basis of useful datas, authors have characterized the analytical points for the purpose of improving products in the preparation of yeast extract.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1539-1545
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• 2010

In beer, glutathione works as the main antioxidant compound, which also correlates with the stability of the beer flavor. In addition, high residual sugars in beer contribute to major nonvolatile components, which are reflected in a high caloric content. Therefore, in this study, the Saccharomyces cerevisiae GSH1 gene encoding glutamylcysteine synthetase and the Saccharomycopsis fibuligera ALP1 gene encoding ${\alpha}$-amylase were coexpressed in industrial brewing yeast strain Y31 targeting the ${\alpha}$-acetolactate synthase (AHAS) gene (ILV2) and alcohol dehydrogenase gene (ADH2), resulting in the new recombinant strain TY3. The glutathione content in the fermentation broth of TY3 increased to 43.83 mg/l as compared with 33.34 mg/l in the fermentation broth of Y31. The recombinant strain showed a high ${\alpha}$-amylase activity and utilized more than 46% of the starch as the sole carbon source after 5 days. European Brewery Convention tube fermentation tests comparing the fermentation broths of TY3 and Y31 showed that the flavor stability index for TY3 was 1.3-fold higher, whereas its residual sugar concentration was 76.8% lower. Owing to the interruption of the ILV2 gene and ADH2 gene, the contents of diacetyl and acetaldehyde as off-flavor compounds were reduced by 56.93% and 31.25%, respectively, when compared with the contents in the Y31 fermentation broth. In addition, since no drug-resistant genes were introduced to the new recombinant strain, it should be more suitable for use in the beer industry, owing to its better flavor stability and other beneficial characteristics.

• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.615-622
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• 2015

The objectives of this study were to evaluate the sensory properties of various natural flavor enhancers (NFEs) and to understand the effects of NaCl and temperature on the sensory characteristics of these NFEs. Descriptive analysis was conducted to evaluate six types of NFEs: yeast extract-based NFE, three; fish sauce-based NFE, one; soy sauce-based NFE, one; and hydrolyzed peptide NFE-based, one. The effects of NaCl (no addition vs. addition) and temperature ($20^{\circ}C$ vs. $55^{\circ}C$) were also evaluated. The results showed that the overall flavor intensity and sensory properties of the NFEs differed greatly depending on the NFE source. Two of the yeast extract-based NFEs elicited higher umami intensity than the other NFEs. Addition of NaCl increased some of the savory-related flavors and the perceived viscosity of the sample. Aroma intensities, in general, were enhanced at the higher temperature, whereas flavor, aftertaste, and mouthfeel attributes were perceived to be stronger at the lower temperature.

• Korean Journal of Human Ecology
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• v.5 no.1
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• pp.48-61
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• 2002

This study was carried out to investigate the effects of four kinds of leavening agents on Jeung-Pyun fermantation. Milk-wine(M), fresh yeast(F), dry yeast(D), instant yeast(I) were used in Jeung-Pyun ingredients. The physicochemical properties, sensory evaluation were examined. The results of this study are summarized as follows: 1. Basic recipes for Jeung-Pyun by preliminary test were developed. 2. Specific volumes and expansion ratio of Jeung-Pyun was higher in the fresh yeast-added sample. 3. The pH of Jeung-Pyun was decreased significantly as the fermentation progressed 4. In the result comparing Jeung-Pyun extracting after 1st fermentation with Jeung-Pyun extracting 2nd fermentation by SEM, the former was widely distributed in stability of bubble and pore than the latter. 5. Standard recipe by Q.D.A. test added four kinds of leavening agents were as follows: (1)Jeung-Pyun added milk wine was 240min for 1st fermentation time, 60min for 2nd fermentation time, 35$^{\circ}C$ for fermentation temperature, 80% for fermentation humidity respectively. (2) Jeung-Pyun added fresh yeast was 90min for 1st fermentation time, 40min for 2nd fermentation time, 35$^{\circ}C$ for fermentation temperature, 80% for fermentation humidity respectively. (3)Jeung-Pyun added dry yeast was 90min for 1st fermentation time, 60min for 2nd fermentation time, 35$^{\circ}C$ for fermentation temperature, 60% for fermentation humidity respectively. (4)Jeung-Pyun added instant yeast was 90min for 1st fermentation time, 40min for 2nd fermentation time, 30$^{\circ}C$ for fermentation temperature, 60% for fermentation humidity respectively. 6.Based on sensory evaluation, Jeung-Pyun added fresh yeast was significantry higher than others in color, sweetness, moistness, softness, and overall quality. There was negative significance between milk wine flavor and astrigentness, and yeast flavor.

• Korean Journal of Food Science and Technology
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• v.13 no.3
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• pp.181-187
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• 1981

The changes in the chemical composition of yeast extracts during autolysis and their effect to the sensory quality were studied with baker's yeast, Saccharomyces cerevisiae. The amounts of extracted solids, proteins, amio-N. amino acids, especially glutamic acid, alanine and lysine, increased by the autolysis time up to 48 hrs. The results of sensory evaluation made by the multiple paired comparision test and Duncan's test indicated a significant difference is taste by the time of autolysis. In the profile test, the flavor character notes expressed by the panel were 17 different characters, 11 in aroma and 6 in taste. The character notes and the intensity of flavor changed with the time of autolysis. The sharp and beany flavor of the extracts which was autolyzed for 4 hours turned into meaty and worty flavor by 48 hours of autolysis. A proper arrangement of the flavor characters in the quantitative descriptive chart could provide a weighted value of the flavor grade. The aroma grade index and the taste grade index correlated to the amplitudes of the profile test.

• Korean journal of food and cookery science
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• v.32 no.1
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• pp.44-49
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• 2016

Organic acid fermentation by yeast an important in the flavor and aroma. June 19th brewing each by each of the kinds of yeast (Instaferm, Instaferm red, La parisienne, La parisienne red, Fermivin, Safbrew wb-06, Safele s-04, Song chun) were analyzed organic acid during storage life. All yeast with reduced organic acid on 4 days. On 10 days, Instaferm, Instaferm red, La parisienne, La parisienne red, Fermivin yeast with the increased organic acid but on 19 days these reduced organic acid and maintain to 28 days. However use of Safbrew wb-06, Safele s-04, Song chun yeast the organic acid at storage and maintain organic acid content to 28 days. The variation of each organic acid during storage life characteristic of the yeast.

• Fisheries and Aquatic Sciences
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• v.26 no.6
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• pp.393-405
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• 2023

The aim of this research was to enhance the flavor of visceral extracts from skipjack tuna. Flavor precursors and the optimum condition for the Maillard reaction were determined. The flavor extract was prepared from the tuna viscera using Endo/Exo Protease controlled in 3 factors; temperature, enzyme amounts and incubation time. The optimal condition for producing tuna viscera protein hydrolysate (TVPH) was 60℃, 0.5% enzyme (w/w) and 4-hour incubation time. TVPH were further processed to tuna viscera flavor enhancer (TVFE) with Maillard reaction. The Maillard reactions of TVFE were conducted with or without supplements such as xylose, yeast extract and methionine. The Maillard volatile components were analyzed with gas chromatography-mass spectrometry. Sixteen volatiles such as 2-methylpropanal, methylpyrazine, 2,5-dimethylpyrazine, dimethyl disulfide and 2-acetylthaizone were newly formed via Maillard reaction and the similarity of volatile contents from TVPH and TVFE were virtualized using Pearson's correlation integrated with heat-map and principal component analysis. To virtualize aromagram of TVPH and TVFE, odor activity value and odor impact spectrum (OIS) techniques were applied. According to OIS results, 3-methylbutanal, 2-methylbutanal, 1-octen-3-ol 2,5-dimethylpyrazine, methional and dimethyl trisulfide were the potent odorants contributed to the meaty, creamy, and toasted aroma in TVFE.

• Preventive Nutrition and Food Science
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• v.6 no.1
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• pp.10-15
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• 2001

Antimicrobial activities of volatile flavor, water and methanol extracts from Agastache rugosa were investigated. The volatile flavor extract was obtained from A. rugosa by simulataneous distillation-extraction (SDE) method. Antimicrobial activity was investigated by disc diffusion method against several microorganisms, four species of Gram positive, three species of Gram negative and tow species of yeast. The volatile flavor extracts had strong antimicrobial activity againstc. utilisand S. cerevisiae. During the growth period, a difference in antimicrobial activity among volatile flavor extracts from A. rugosa was not shown. The water extract of above 10 mg/disc showed antimicrobial activity. Methanol extracts from A. rugosa harvested in June showed antimicrobial activity against tested Gram positive and Gram negative bacteria, showed weak antimicrobial activity against the bacteria from those harvested in July and August. In particular, antimicrobial activity against V. parahaemolyticus was stronger than that against other bacteria. Water and methanol extracts did not inhibit yeast. C. utilis and S. cerevisiae. To further elucidate the effective components, volatile flavor extracts was analyzed by GC/MS. harvested in June, the components included 8 phenols (93.031%), 18 terpenes (5.230%), 12 alcohols (1.300%) 8 alkanes (0.181%), 1 ester (0.056%), 2 ketones (0.033%), 2 aldehydes (0.011%) and 1 pyrrole (0.007%). In July, the components included 6 phenols (94.366%), 19 terpenes (3.394%), 11 alcohols (2.045%), 1 ester (0.039%), 2 ketones (0.028%), 1 furan (0.005%) and 1 aldehyde (0.005%). And in August, the components included 7 phenols (95.270%), 19 terpenes (2.951%), 13 alcohols (1.399%), 1 ester (0.063%), 2 aldehydes (0.016%), 2 ketones (0.011%), 1 alkane (0.006%), 1 acid (0.005%) and 1 pyrrole (0.005%). The major component of volatile flavors was estragole, a phenolic compound.