• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.3
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• pp.382-387
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• 2001

Characteristics of six commercial samjangs were analyzed such as proximate composition, free amino acids, organic acids and free sugars. Also color, taste and odor were evaluated by 36 panelists. They were composed of moisture content 41.4-48.4%, crude protein 9.2-10.4%, crude fat 2.2-3.4%, pH 5.3-5.7, amino nitrogen 194.0%-375.6 mg% and sodium chloride 7.7-9.1%. Total free amino acids of samjangs were 975.89-2304.98 mg%. Glutamic acid was the highest amino acid among free amino acids as 231.7-788.01 mg%. Proline, arginine, alanine and lysine were higher than other free amino acids while histidine, cystine and methionine were lower than other. Eleven free amino acids including glutamic acid were the highest in samjang (B) which contained more doenjang than any other makers did. Total organic acids were 401.01-640.27 mg%. 69.65-269.07 mg% of succinic acid was the highest among organic acids. Lactic acid was the highest in samjang (F) which was home made. Total free sugars was the highest in samjang (A) which contained more wheat flour than any other makers did it. Glucose was 9.30-23.99% and fructose was nd-2.69%. The result of proximate composition showed a different pattern comparing with that sensory evaluation. Samjang (A) which contained less salt showed the highest overall acceptability while samjang (F) which contained more dark color, more salt was the lowest one among the samples.

• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.579-585
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• 2015

Following supplementation with organic acids (acetic, citric, and lactic acids), the pH of the alcohol mash changed from 4.2 control to 3.73-3.97 supplemented, the acidity from 5.06 to 8.13-9.98, and the alcohol content from 17.8 to 17.0-17.8%. Protease activity decreased owing to the pH change, and the total nitrogen content decreased by 13.1-36.9% following organic acid supplementation. Organic acid supplementation did not affect the distillation efficiency; however, thiobarbituric acid values in the crude distillate (40%) decreased 2.2-3.6 fold following supplementation with citric acid and lactic acid. The total isobutanol (B), isoamyl alcohol (A), and 1-propanol (P) contents in each soju (25%) supplemented with organic acid were 1,041.47, 979.50, and 961.48 ppm, respectively, which were higher than those in the control soju (935.27 ppm). The A/P, A/B, and B/P ratios of soju were altered and the acetaldehyde content decreased following supplementation with the organic acid.

• Korean journal of food and cookery science
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• v.7 no.1
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• pp.15-25
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• 1991

The effects of lactic acid bacteria on the chemical and microbial changes of fermented kimchi at various temperatures were studied. Kimchi was homogenized and was sterilized by ultra violet, then Lactobacillus plantarum, Leuconostoc mesenteroides, Pediococcus acidilactici, Lactobacillus brevis and the mixture of there bacteria inoculated on sterilized kimchi, respectively. The measurement of pH and total acidity, quantitative analysis of volatile organic acids and nonvolatile organic acids by gas chromatography were investigated while inoculated kimchi were fermented at $30^{\circ}C$, $21^{\circ}C$, $14^{\circ}C$ and $7^{\circ}C$. Sample I (original kimchi homogenate), Sample III (inoculated with Leuconostoc mesenteroides) and Sample Ⅵ (inoculated with mixed lactic acid bacteria) were alike in that changes of pH and total acidity and especially, these phenomena were prominent at $14^{\circ}C$. Formic, acetic and heptenoic acid as volatile organic acid were detected by GC, and these acids formed mainly by Leuconostoc mesenteroides and lactobacillus brevis. Sample III was more higher content than other samples at $14^{\circ}C$. As nonvolatile organic acid, lactic acid in all samples, citric acid in sample III at $21^{\circ}C$and $14^{\circ}C$, succinic acid in sample I at $30^{\circ}C$, $21^{\circ}C$, $14^{\circ}C$ and sample V at $30^{\circ}C$ were detected by GC.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.6
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• pp.1065-1070
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• 1998

Lactic acid bacteria KL 1, KD 6, KL 4 strains isolated from kimchi, or obtained Lactobacillus acidophilus, Lactobacillus plantarum, Leuconostoc mesenteroides with and without yeast(Saccharomyces cerevisiae) were inoculated in fruit vegetable juice for mixed culture fermentation 3 days at 3$0^{\circ}C$, and then their chemical changes were studied during fermentation. The amount of organic acid produced by the mixed culture fermentation of KL 1 and yeast was 0.82%(3 days) or 0.58%(1 day) and with the final pH of 3.3(3 days) or 4.2(1 day). These mixed culture systems of isolated strains or other bacterial strains had almost similar results of growth rate and acid production. The contents of vitamin C and carotene were retained and stabilized as 70~80% level of their initial values after 24 hrs fermentation. And also ethanol was produced as of the range in 9.6mg%(W/V) by the mixed culture fermentation of KL 1 and yeast, however, the content of ethanol in single culture fermentation by KL 1 strain was much lower than that of mixed culture. The major components of organic acids in fermented juice by mixed culture were considered as malic(26.0%), lactic(49.9%), succinic and citric acid, whereas these of unfermented juice were malic(53.2%), citric and other acids. On other hand, reducing sugar was decreased from 18.3mg/ml in fresh juice to about 12mg/ml in juice by mixed culture fermentation. Concentrations of fructose, glucose and sucrose were also greatly reduced in fermented juice.

• Journal of Ginseng Research
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• v.42 no.1
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• pp.57-67
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• 2018

Background: Ginseng contains many small metabolites such as amino acids, fatty acids, carbohydrates, and ginsenosides. However, little is known about the relationships between microorganisms and metabolites during the entire ginseng fermentation process. We investigated metabolic changes during ginseng fermentation according to the inoculation of food-compatible microorganisms. Methods: Gas chromatography mass spectrometry (GC-MS) datasets coupled with the multivariate statistical method for the purpose of latent-information extraction and sample classification were used for the evaluation of ginseng fermentation. Four different starter cultures (Saccharomyces bayanus, Bacillus subtilis, Lactobacillus plantarum, and Leuconostoc mesenteroide) were used for the ginseng extract fermentation. Results: The principal component analysis score plot and heat map showed a clear separation between ginseng extracts fermented with S. bayanus and other strains. The highest levels of fructose, maltose, and galactose in the ginseng extracts were found in ginseng extracts fermented with B. subtilis. The levels of succinic acid and malic acid in the ginseng extract fermented with S. bayanus as well as the levels of lactic acid, malonic acid, and hydroxypruvic acid in the ginseng extract fermented with lactic acid bacteria (L. plantarum and L. mesenteroide) were the highest. In the results of taste features analysis using an electronic tongue, the ginseng extracts fermented with lactic acid bacteria were significantly distinguished from other groups by a high index of sour taste probably due to high lactic acid contents. Conclusion: These results suggest that a metabolomics approach based on GC-MS can be a useful tool to understand ginseng fermentation and evaluate the fermentative characteristics of starter cultures.

• Restorative Dentistry and Endodontics
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• v.40 no.3
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• pp.188-194
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• 2015

Objectives: This study evaluated the effect of lactic acid and acetic acid on the microhardness of a silorane-based composite compared to two methacrylate-based composite resins. Materials and Methods: Thirty disc-shaped specimens each were fabricated of Filtek P90, Filtek Z250 and Filtek Z350XT. After measuring of Vickers microhardness, they were randomly divided into 3 subgroups (n = 10) and immersed in lactic acid, acetic acid or distilled water. Microhardness was measured after 48 hr and 7 day of immersion. Data were analyzed using repeated measures ANOVA (p < 0.05). The surfaces of two additional specimens were evaluated using a scanning electron microscope (SEM) before and after immersion. Results: All groups showed a reduction in microhardness after 7 day of immersion (p < 0.001). At baseline and 7 day, the microhardness of Z250 was the greatest, followed by Z350 and P90 (p < 0.001). At 48 hr, the microhardness values of Z250 and Z350 were greater than P90 (p < 0.001 for both), but those of Z250 and Z350 were not significantly different (p = 0.095). Also, the effect of storage media on microhardness was not significant at baseline, but significant at 48 hr and after 7 day (p = 0.001 and p < 0.001, respectively). Lactic acid had the greatest effect. Conclusions: The microhardness of composites decreased after 7 day of immersion. The microhardness of P90 was lower than that of other composites. Lactic acid caused a greater reduction in microhardness compared to other solutions.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.4
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• pp.270-275
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• 2022

Livestock production costs are heavily influenced by the cost of feed, The use of domestically grown forages is more desirable for livestock feed production. As part of this study, triticale, which is an extremely palatable and easily cultivable crop in Korea, was used to produce low moisture silage bales with lactic acid bacteria (LAB) and then stored for different periods. We examined the nutrient content of silage, such as crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF), as well as their organic acids, including lactic acid, acetic acid, butyric acid, at different storage periods. The nutrient content of silages, such as crude protein, ADF, and NDF, did not change significantly throughout storage periods. Organic acid data indicated that lactic acid concentrations increased with increasing moisture contents and storage periods up to nine months. However, further extending storage to 12 months resulted in a reduction in the lactic acid content of all silages as well as an increase in their pH. Based on the present results, it suggested that the production of low moisture silage with the LAB may be able to preserve and maintain its quality without altering its nutritional composition. Also, the lactate content of the silage remained significant for at least nine months.

• Journal of Mushroom
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• v.11 no.4
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• pp.187-193
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• 2013

A galactose fermentation bacterium producing lactose from red seaweed, which was known well to compromise the galactose as main reducing sugar, was isolated from button mushroom bed in Buyeo-Gun, Chungchugnamdo province. The lactic acid bacteria MONGB-2 was identified as Lactobacillus paracasei subsp. tolerans by analysis of 16S rRNA gene sequence. When the production of lactic acid and acetic acid by L. paracasei MONGB-2 was investigated by HPLC analysis with various carbohydrates, the strain MONGB-2 efficiently convert the glucose and galactose to lactic acid with the yield of 18.86 g/L and 18.23 g/L, respectively and the ratio of lactic acid to total organic acids was 1.0 and 0.91 g/g for both substrates. However, in the case of acetic acid fermentation, other carbohydrates besides galactose and red seaweed hydrolysate could not be totally utilized as carbon sources for acetic acid production by the strain. The lactic acid production from glucose and galactose in the fermentation time courses was gradually enhanced upto 60 h fermentation and the maximal concentration reached to be 16-18 g/L from both substrates after 48 h of fermentation. The initial concentration of glucose and galactose were completely consumed within 36 h of fermentation, of which the growth of cell also was maximum level. In addition, the bioconversion of lactic acid from the red seaweed hydrolysate by L. paracasei MONGB-2 appeared to be about 20% levels of the initial substrates concentration and this results were entirely lower than those of galactose and glucose showed about 60% of conversion. The apparent results showed that L. paracasei MONGB-2 could produce the lactic acid with glucose as well as galactose by the homofermentation through EMP pathway.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.215-223
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• 2009

This study was conducted to investigate the effect of diets supplemented with different levels (0, 2.5, 5.0, and 7.5%) of yuza (Citrus junas Sieb ex Tanaka) on nutritional composition of olive flounder. Four groups of fish (242.2$\pm$14.2 g) were fed to apparent satiation twice daily for 4 months. There were no significant differences in proximate composition among the treatment groups (P<0.05). Vitamin C content in flounder muscle was higher in the yuza-added groups than in the control group, and the content among the treatment groups increased as amount of yuza added to diets increased (P<0.05). Of the eight organic acids in flounder muscle, lactic acid was predominant, followed by oxalic acid, succinic-acid, tartaric acid, and acetic acid. Flounders fed 2.5% yuza diet had the highest lactic acid content of all treatments. Four sugars were found in all groups and glucose was the major sugar. Glucose and ribose were detected as the highest sugars in the 2.5% treatment, while maltose and galactose were the dominant sugars in the 5.0% treatment. The abundant fatty acids in fed flounders were 22:6n-3 (DHA), 16:0, and l8:1n-9, which were composed of over 60% of total fatty acids. The control and the 7.5% treatment group had higher 22:6n-3 (DHA) content than the other groups. Major amino acids in samples were glutamic acid, aspartic acid, lysine, leucine, valine, arginine, and alanine. The 2.5% yuza treatment had the highest content of total amino acids and essential amino acids. There were little differences in the free amino acid compositions among the treatments. However, taurine was the predominant amino acid and made up over 47% of total free amino acids. The 2.5% added yuza group contained higher amount of sweet amino acids such as alanine, serine, proline, glycine than the other groups. The addition of yuza to diet of olive flounder had no or little effect on the nutritional components of olive flounder except for vitamin C. However, the 2.5% yuza added group had the highest nutritional values of the treatment groups.

• Journal of Microbiology and Biotechnology
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• v.3 no.2
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• pp.129-133
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• 1993

The effect of different compositions of organic acids on the flavor profile of 10% sugar solution was investigated by the response surface methodology, and the results were used to evaluate the flavor characteristics of lactic acid fermented cereal beverages. A mixture of extruded rice flour (10%) and soymilk (7.8% dry matter) was fermented with Leuconostoc mesenteroides (Sikhae). Depending on the substrate pretreatments, for example, the malt or amylase digestion and the proteolytic enzyme hydrolysis, the sugar and organic acid composition of the product varied. The organic acid composition of the fermented beverages was in the ranges of 0.44-0.55% lactic acid, 0.05-0.09% acetic acid and 0.07-0.09% citric acid, while that of commercial apple juice was 1.59% malic acid and 0.49% acetic acid. The flavor profiles of fermented beverages added with 10% sucrose were compared to those of apple juice and a model mixture containing 0.48% citric acid, 0.39% lactic acid and 0.12% acetic acid in 10% sugar solution. The QDA diagram of fermented beverages approached to that of apple juice, when the substrate was digested by amylase but not by protease.