• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.612-617
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• 1995

Changes in titratable acidity, pH, viable cells, sensory properties and volatile aroma compounds of yogurt during lactic fermentation in milk added with egg white powder (EWP) have been studied. Milk added with 1% or 2% (W/V) of EWP was fermented with Lactobacillus acidophilus for 30 hr. Acidity of milk added with EAT increased gradually during lactic fermentation for 30 hr, pH dropped gradually and number of viable cells increased and reached stationary phase at about 9 hr. Addition of EWP significantly stimulated acid production by lactic acid bacteria and stimulating effect of 2% EWP addition on acid production was slightly higher than that of 1% EWP addition. Sensory evaluation showed that optimum fermentation time of yogurt prepared from milk added with 2% of EWP was about 15 hr. Gas chromatographic analysis showed that the amount of acetone and butanol decreased gradually and that of ethanol increased until 30 hr. Diacetyl and acetoin were first detected after 6hr and 9hr, respectively, and then increased until 30 hr.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.2
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• pp.207-214
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• 2011

We investigated the quality characteristics of fermented ginseng Yakju produced using different percentage contents and application dates of ginseng. Although the pH of fermented ginseng Yakju was not significantly different among the various treatment groups, the total acidity was changed depending on the percentage of ginseng content. the application date of ginseng did not influence the total acid content. The amount of volatile acids was higher at a 0.2~0.3% content of white or red ginseng than in other treatment groups. The ginsenoside contents of white and red ginseng used for making ginseng Yakju were 3,555.0 and 4,447.4 ppm, respectively. In ginseng Yakju, total ginsenoside contents were detected at very small amounts of <10 ppm. A total of 15 volatile components were detected in ginseng Yakju. Higher levels of methanol were produced at early application dates. In sensory evaluations, the preference for aroma was higher at white ginseng levels of 0.5% and 1.0% than for other treatment groups, and the taste was judged to be best at a white ginseng content of 0.3%. In the red ginseng treatment group, a red ginseng content of 0.3% was most preferred for both aroma and taste. The taste preference for white ginseng was at 4 days after application, while the taste of the red ginseng treated group was good at the beginning of fermentation.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.6
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• pp.543-549
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• 2016

The objective of this study was to investigate quality properties of 'Cheonghyang' wine using different commercial yeast strains. Soluble solid content, pH level and total acidity of 'Cheonghyang' grape were $20^{\circ}Bx$, pH 3.5 and 0.66%, respectively. Total acidity ranged from 0.91~1.06% in the middle stage of fermentation and decreased to 0.77~0.82% when alcoholic fermentation finished. Alcohol content in wines ranged from 12.5% to 12.9% showing no significant difference in yeast strains. Wine fermented with Red Fruit had high volatile acid content (189.0 mg/L) whereas wine fermented with Fermivin indicated low volatile acid content (77.7 mg/L). Wines made with Montrachet, Fermivin and Aroma White had low brightness (L-value) compared to others. Results from sensory evaluation demonstrated that commercial wine yeasts, Montrachet and Fermivin, can be applied to improve sensory properties of 'Cheonghyang' wine such as aroma, acidity and transperency. On the other hand, preferences of wine fermented with EC-1118 strain containing lots of tannins and total polyphenols were significantly reduced.

• Korean Journal of Food Science and Technology
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• v.43 no.4
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• pp.419-425
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• 2011

Changes in the flavor of muskmelons stored at different temperatures were examined to judge aroma patterns during storage. A mass-spectrometry based electric nose was used to distinguish the subtle differences in the muskmelon's volatile compounds. The data were used for a discriminant function analysis (DFA), and then the partial least square algorithm was used for a quantitative analysis. Volatile components in the muskmelons increased with storage, and the first discriminant function score (DF1: $r^2$=99.88%, F=3072.5) moved from a positive position to a negative position as the storage period increased. The proper point of maturity was anticipated as the $28^{th}$ day at 0$^{\circ}C$, $21^{st}C$ day at 4 and 7$^{\circ}C$, and $14^{th}$ day at 10$^{\circ}C$. Also, using the DF1 score we could predict the general tendency (vitamin C, stem moisture, acidity) of the muskmelons. The electronic nose revealed that the major volatile compounds that changed during storage of the melons were ethyl ethyl acetate, butyl acetate, nonanol, dodecanoic acid, hexadecanoic acid and tricosane. The amount of volatile compounds detected increased during storage.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.2
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• pp.293-300
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• 2018

Objective: This study observed the effects of cooking method and final core temperature on cooking loss, lipid oxidation, aroma volatiles, nucleotide-related compounds and aroma volatiles of Hanwoo brisket (deep pectoralis). Methods: Deep pectoralis muscles (8.65% of crude fat) were obtained from three Hanwoo steer carcasses with $1^+$ quality grade. Samples were either oven-roasted at $180^{\circ}C$ (dry heat) or cooked in boiling water (moist heat) to final core temperature of $70^{\circ}C$ (medium) or $77^{\circ}C$ (well-done). Results: Boiling method reduced more fat but retained more moisture than did the oven roasting method (p<0.001), thus no significant differences were found on cooking loss. However, samples lost more weight as final core temperature increased (p<0.01). Further, total saturated fatty acid increased (p = 0.02) while total monounsaturated fatty acid decreased (p = 0.03) as final core temperature increased. Regardless the method used for cooking, malondialdehyde (p<0.01) and free iron contents (p<0.001) were observed higher in samples cooked to $77^{\circ}C$. Oven roasting retained more inosinic acid, inosine and hypoxanthine in samples than did the boiling method (p<0.001), of which the concentration decreased as final core temperature increased except for hypoxanthine. Samples cooked to $77^{\circ}C$ using oven roasting method released more intense aroma than did the others and the aroma pattern was discriminated based on the intensity. Most of aldehydes and pyrazines were more abundant in oven-roasted samples than in boiled samples. Among identified volatiles, hexanal had the highest area unit in both boiled and oven-roasted samples, of which the abundance increased as the final core temperature increased. Conclusion: The boiling method extracted inosinic acid and rendered fat from beef brisket, whereas oven roasting intensified aroma derived from aldehydes and pyrazines and prevented the extreme loss of inosinic acid.

• Bulletin of the Korean Chemical Society
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• v.25 no.2
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• pp.271-279
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• 2004

The aroma component of Hallabong peel has been characterized by GC-MS with two different extraction techniques: solid-phase trapping solvent extraction (SPTE) and headspace solid-phase microextraction (HSSPME). Aroma components emitted from Hallabong peel were compared with those of other citrus varieties: lemon, orange and grapefruit by SPTE and GC-MS. d-Limonene (96.98%) in Hallabong was the main component, and relatively higher peaks of cis- ${\beta}$-ocimene, valencene and -farnesene were observed. Other volatile aromas, such as sabinene, isothujol and ${\delta}$-elemene were observed as small peaks. Also, principal components analysis was employed to distinguish citrus aromas based on their chromatographic data. For HSSPME, the fiber efficiency was evaluated by comparing the partition coefficient ($K_{gs}$Kgs) between the HS gaseous phase and HS-SPME fiber coating, and the relative concentration factors (CF) of the five characteristic compounds of the four citrus varieties. 50/30 ${\mu}$m DVB/CAR/PDMS fiber was verified as the best choice among the four fibers evaluated for all the samples.

• Microbiology and Biotechnology Letters
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• v.27 no.3
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• pp.236-245
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• 1999

Andong Soju is a Korean traditional distilled liquor brewed with Nuruk which is cultured with wild microorganisms. To provide useful information for scientific production and systematic quality control of traditional distilled liquor, the effects of mixed culture of the alcoholic yeasts and saccharifying molds isolated from the Nuruk, and mashes on the flavor and sensory characteristics were investigated. Distillate from mashes cocultured with Saccharomyces cerevisiae and Hansenula anomala using Mucor Nuruk was compared with distillate from mashes brewed with Andong Nuruk and with distillate from plant fermented mashes to analyze their flavor characteristics. The volatile flavor compounds in distillates were analyzed by GC and GC-MS using direct injection, solvent extraction, and purge & trap methods. Alcohols such as 3-methyl-1-butanol, 2-methyl-1-propanol, 1-propanol, and 2-phenyl ethanol; aldehydes such as acetaldehyde and 2-furancar-boxaldehyde; esters such as ethyl ester of acetic acid, hexanoic acid, octanoic acid, decanoic acid; alkanes, alkenes, ketone, sulfur, and pyrone compounds were detected. Alcohols were chief components of flavor compounds. No significant difference in overall acceptability test was shown among three experimental groups(p<0.05), but Nuruk-like aroma, Kaoliangchiew-like aroma, sweet taste, and well rounded mouthfeel showed significant differences among them(p<0.05).

• Preventive Nutrition and Food Science
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• v.4 no.1
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• pp.18-22
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• 1999

Flavor characteristics of raw Cordyceps militaris significatntly different from those of dried one. In the case of raw Cordyceps militaris , major flavor components were composed of 5 alcohols, 3 ketones, 4 phenols, 9 alkanes , and 3 alkenes. The major alcohol was 1-octen-3-ol(22.56%, 1147.3% ng/ml), which contributed to the characteristic green flavor. Ketones (3-ocatone, inparticular )were present in the highest concentration in raw Cordyceps militaris . In contrast, major flavor components of dried Cordyceps militaris were composed of 4 alcohols, 4 ketones, 3 furans, 4 pyrizines, 2 dithiazines, 5 phenols , 8alkenes , 17 alkanes, and 8 fatty acids. Dried Cordyceps militaris had unique sweet aroma of sesame as wella s a milky flavor. Green or fruit flavor were rarely detected . In alkanes , 10 cosanes, component fo wax were present. Typical flavor components of alkanes such as $\beta$-caryophyllen and Δ-cadinene were also detected. Fatty acids of dried Cordyceps militaris ranged from myristic acid (14 :0) to linoleic acid (18 ; 2). The sweet aroma of dried Cordyceps militaris was mostly due to pryazines, dithaiazines, and furans. Two dithaizines were identified and characteristics of these flavor components was a roasted bacon flavor. Strong antibacterial acitivity was observed toward Vibrio spp. such as V. vulnificus, V.cholerae, V. parahaemlyticus. Relatively high antibacterial acitivity was shown toward Bacillus subtilis , B,cereus, Staphyllococcus aureus, and Corynebacterium xerosis.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.536-541
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• 1991

To enhance the productivity of fruit flavor compounds from whey by the lactose fermenting yeast, Kluyveromyces lactzs ATCC 8585 was treated with N-methyI-N'-nitro-N-nitrosoguanidine (NTG). After the NTG treatments, a mutant showing resistance to antifungal activity of geraniol, and strong fruity but low yeasty flavor was selected and named as K. lactis 450 K. Flavor compounds from 3-day culture broth were extracted with pentane-dichloromethane (2:l) and the concentrated oleoresins were analyzed by gas chromatography. The mutant strain produced more classes and larger amount of flavor compounds than the parent stlain. Tentatively identified volatile compounds from the culture of the mutant were: terpenes such as myrcenol; alcohols such as cis-3-hexenol, n-hexanol; esters such as ethyl isovalerate, cis- 3-hexenyl n-butyrate, n-amyl-n-hexanoate, phenyl ethyl n-propioate; ketones such as methyl vinyl ketones; other compounds such as vanillin, 3-methylcoumarin.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.3
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• pp.259-272
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• 2020

Nowadays, two types, Yumhae and Sikhae methods, remained as traditional seafood fermentation methods in Korea. In this study, flavor compounds in two types of salt-fermented fishes made by Yumhae method such as anchovy Engraulidae sp., shrimp Caridea sp., squid Decapodiformes sp., big eyed herring Clupea sp., gizzard shad Dorosoma sp. and hairtail Trichiurus sp., and made by Sikhae method such as Alaska pollack Gadus Chalcogrammus and squid. Volatile compounds detected in all salt-fermented fishes were composed mainly of aldehydes (45), ketones (39), alcohols (45), acids (12), esters (47), N-containing compounds (43), aromatic hydrocarbons (37), S-containing compounds (26), furans (10), and miscellaneous compounds (40) in salt-fermented fishes made by Yumhae method. Meanwhile, alcohols (47), terpenes (38), S-containing compounds (22), carbonyl compounds (19 aldehydes, 18 ketones), esters (13), and acids (14). Aroma-active compounds were identified by Gas chromatography/mass spectrometry/olfactometry and aroma extract dilution analysis in salt-fermented anchovy, shrimp and tuna (Thunnini sp.) sauce. Ethyl 2-methylbutanoate (candy/sweet) and 2-ethyl-3,5-dimethylpyrazine (nutty/baked potato-like) were predominant odorants in salt-fermented anchovy, whereas dimethyl trisulfide (cooked cabbage/soy sauce-like), 2-ethyl-3,5-dimethylpyrazine, and (E,E)-2,4-heptadienal (fatty/grainy) in salt-fermented shrimp, and dimethyl trisulfide, 3-methylbutanal (dark chocolate-like), and 3-methylthiopropanal (baked potato-like) in tuna sauce.