• Journal of Applied Biological Chemistry
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• v.63 no.4
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• pp.429-437
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• 2020

This study aimed to investigate the change in physicochemical properties and lactic acid bacterial communities during kimchi fermentation at different temperatures (8, 15, and 25 ℃) using two molecular genetics approaches, multiplex polymerase chain reaction and 16S rRNA gene sequencing. The pH during fermentation at 8, 15, and 25 ℃ decreased from 6.17 on the initial fermentation day to 3.92, 3.79, and 3.48 after 54, 30, and 24 days of fermentation, respectively, while the acidity increased from 0.24% to 1.12, 1.35, and 1.54%, respectively. In particular, the levels of lactic acid increased from 3.74 g/L on the initial day (day 0) to 14.43, 20.60, and 27.69 g/L during the fermentation after 24, 18, and 12 days at 8, 15, and 25 ℃, respectively, after that the lactic acid concentrations decreased slowly. The predominance of lactic acid bacteria (LAB) in the fermented kimchi was dependent on fermentation stage and temperature: Lactobacillus sakei appeared during the initial stage and Leuconsotoc mesenteroides was observed during the optimum-ripening stage at 8, 15, and 25 ℃. Lac. sakei and Lactobacillus plantarum grew rapidly in kimchi produced at 8, 15, and 25 ℃. In addition, Weissella koreensis first appeared at days 12, 9, and 6 at 8, 15, and 25 ℃ of fermentation, respectively. This result suggests that LAB population dynamics are rather sensitive to environmental conditions, such as pH, acidity, salinity, temperature, and chemical factors including free sugar and organic acids.

• Journal of Microbiology and Biotechnology
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• v.34 no.8
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• pp.1727-1737
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• 2024

The quality of tobacco is directly affected by macromolecular content, fermentation is an effective method to improve biochemical properties. In this study, we utilized CBHA (cellobiohydrolase A) glycosylase, which was expressed by Pichia pastoris, as an additive for fermentation. The contents of main chemical components of tobacco leaves after fermentation were determined, and the changes of microbial community structure and abundance in tobacco leaves during fermentation were analyzed. The relationship between chemical composition and changes in microbial composition was investigated, and the function of bacteria and fungi in fermentation was predicted to identify possible metabolic pathways. After 48 h of CBHA fermentation, the contents of starch, cellulose and total nitrogen in tobacco leaf decreased by 17.60%, 28.91% and 16.05%, respectively. The microbial community structure changed significantly, with Aspergillus abundance decreasing significantly, while Filobasidum, Cladosporium, Bullera, Komagataella, etc., increased in CBHA treated group. Soluble sugar was most affected by microbial community in tobacco leaves, which was negatively correlated with starch, cellulose and total nitrogen. During the fermentation process, the relative abundance of metabolism-related functional genes increased, and the expressions of cellulase and endopeptidase also increased. The results showed that the changes of bacterial community and dominant microbial community on tobacco leaves affected the content of chemical components in tobacco leaves, and adding CBHA for fermentation had a positive effect on improving the quality of tobacco leaves.

• Journal of Microbiology and Biotechnology
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• v.28 no.1
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• pp.50-58
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• 2018

Elephant garlic (Allium ampeloprasum var. ampeloprasum), which belongs to the Alliaceae family along with onion and garlic, has a flavor and shape similar to those of normal garlic but is not true garlic. Additionally, its properties are largely unknown, and its processing and product development have not been reported. In this study, we focused on using elephant garlic to produce a new type of vinegar, for which the market is rapidly growing because of its health benefits. First, we evaluated the effects of elephant garlic addition on acetic acid fermentation of rice wine by Acetobacter pasteurianus. In contrast to normal garlic, for which 2% (w/v) addition completely halted fermentation, addition of elephant garlic enabled slow but successful fermentation of ethanol to acetic acid. Metabolite analysis suggested that sulfur-containing volatile compounds were less abundant in elephant garlic than in normal garlic; these volatile compounds may be responsible for inhibiting acetic acid fermentation. After acetic acid fermentation, vinegar with elephant garlic did not have any sulfur-containing volatile compounds, which could positively contribute to the vinegar flavor. Moreover, the amino acid profile of the vinegar suggested that nutritional and sensory properties were more enhanced following addition of elephant garlic. Thus, elephant garlic may have applications in the development of a new vinegar product with improved flavor and quality and potential health benefits.

• Korean Journal of Medicinal Crop Science
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• v.28 no.5
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• pp.347-353
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• 2020

Background: Fermentation of medicinal plants increases their absorption rate and bioavailability in the body. Astragalus membranaceus has been used as a raw material, but research in its use as a food ingredient is lacking. Therefore, the purpose of this study was to identify the physicochemical characteristics and anti-inflammatory effect of fermented Astragalus membranaceus. Methods and Results: Astragalus roots were fermented using Aspergillus awamori for 4 days and their extracts prepared using hot water. The pH, total acidity (%), and reducing sugar (%) of the extracts were then investigated. The pH and total acidity decreased during fermentation. After fermentation, the pH and total acidity decreased, whereas the reducing sugar level increased. The active ingredients in fermented Astragalus were calycosin-7-O-ßd-glucoside, ononin, calycosin and formononetin. The calycosin contents was highest in the hot-water extracted samples fermented for 4 days. The other components were similar to those in control. Nitric oxide level was lower in the hot-water extracted samples fermented for 4 days than in lipopolysaccharide control group. The sample fermented for 4 days was confirmed to inhibit the production of tumor necrosis factor-α and interleukin-1β. Conclusions: Our results showed the physicochemical properties and anti-inflammatory effects of A. membranaceus after fermentation using Aspergillus awamori. These results indicated that fermented Astragalus membranaceus can be used as a functional food.

• Journal of the Korean Society of Food Culture
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• v.4 no.2
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• pp.167-172
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• 1989

Kimchi during fermentation with different periods of storage at room temperature were evaluated for the textural properties, titratable acidity, pH value and thickness of leaves in salting, during fermentation. Thickness of internal leaves in Korean cabbage were decreased of 50% for external leaves. but less decreased on the thickness of leaves in salting. Cutting force of leaves were increased with salting and during kimchi fermentation before 7 days. Stress (force vs area) in kimchi and Korean cabbage was same result of cutting force. Equation of pH change was y=-0.23x+6.13 (r=-0.97). Titratable acidity equation was y=0.09x-0.01(r=0.96). A desirable pH value and titratable acidity were 4.2 and 0.63% in kimchi fermentation.

• Journal of the Korean Home Economics Association
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• v.46 no.3
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• pp.49-55
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• 2008

The purpose of this study was to investigate the effects of green tea extracts (GTE) on the fermentation properties of polyphenol-enriched beers. As such, the formation patterns of tannoid in beer with GTE were investigated at 3 different infusion times, while the ale and the lager beers fortified with GTE were analyze to ascertain effects on gravity, pH, yeast viability, total polyphenol, and tannoid during fermentation period. The results were as follows: 1) The formation of tannoid in beer with GTE in the tannometer; In reaction of GTE with polyvinylpyrrolidon (PVP), control lager beer peaked in the formation of tannoid at $70\;{\sim}\;80\;mg$ of PVP, the 1st extract exceeded the detection limit, the 2nd extract at $170\;{\sim}\;180\;mg$, while the third extract at $150\;{\sim}\;160\;mg$ of PVP. The GTE were slow in reacting with PVP, and their formation patterns were different from those of polyphenols from barley and hop. 2) Ale fermentation; The final alcohol content was 9.25% (ABV). The addition of GTE increased the yeast viability after 2 days and finally reached 52.3% from 30.9%. Total polyphenol in GTE beer increased by 1.5 times (p < .05). However, its tannoid contents increased by 6.4 times. 3) Lager fermentation; The final alcohol content was 5.93% (ABV). The effect of GTE on lager beer was minimal for all variables. However, total polyphenol of GTE beer increased by 1.4 times (p < .05). Its tannoid increased by 3.3 times (p < .05).

• Korean Journal of Agricultural Science
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• v.43 no.3
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• pp.424-431
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• 2016

The nutrients in livestock manure produced during fermentation processes in public livestock recycling centers are used as fertilizers. However, the large amounts of swine manure produced in intensive livestock farms can be a nonpoint source of pollution. In this experiment, we investigated the chemical properties, inorganic components, and heavy metal contents in 101 samples of liquid swine manure collected from 28 public livestock recycling centers throughout the nation. Results showed that the average pH of the samples was alkaline (pH range 5.18 to 9.54), and their maximum EC was $53.2dS\;m^{-1}$. The amounts of total nitrogen and total phosphorus were in the range of 1000 - 2000 and $200-800mg\;L^{-1}$ while potassium, which constituted 47% of the total inorganic ions recovered from the liquid swine manure, amounted to $1500mg\;L^{-1}$. The most distinctive heavy metals recovered from the liquid swine manure were copper and zinc although the amounts of both heavy metals were much lesser than those of the standards as livestock liquid fertilizer set by the Rural Development Administration. On the other hand, the amount of nitrogen decreased rapidly with an increasing fermentation period from immature to mature, assumed to be lost as volatile compounds, such as ammonia, which are the major odor components during the fermentation process.

• Journal of the Korean Society of Food Culture
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• v.33 no.5
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• pp.458-463
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• 2018

This study was conducted to investigate the quality characteristics of peach jelly following the addition of various gelling agents (locust bean gum, carrageenan, xanthan gum). The various gelling agents were added to peach jelly at five levels (1.0, 1.5, 2.0, 2.5 and 3.0%), after which their effects on physicochemical properties, textural properties and sensory qualities were investigated. The total titratable acidity (TTA) of peach jelly was decreased with increases in gelling agent. Additionally, the sweetness and pH of peach jelly increased significantly as the amount of various gelling agents increased. Moreover, the lightness (L-value), redness (a-value) and yellowness (b-value) of peach jelly was decreased as the amount of gelling agent. Furthermore, the hardness, gumminess and chewiness of the peach jelly increased as the amount of gelling agent increased. Finally, the overall acceptance was higher for jelly containing 2.0% added gelling agent than for other samples. Based on the results of this study, it is recommended that mixed gelling agents be added to peach jelly at 2.0%.

• Animal Bioscience
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• v.35 no.1
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• pp.39-46
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• 2022

Objective: The fermentation profile and silage quality of 3 Italian ryegrass (Lolium multiflorum Lam.) cultivars (cvs. Devis, Hellen, and Trinova) treated with 5 nitrogen doses (0, 50, 100, 150, and 200 kg/ha) were evaluated. Methods: The experiment was laid out in split plot in randomized complete block design with three replications. Annual ryegrass cultivars used in this study have been commonly grown in Turkey. Nitrogen doses were set in main plot and cultivars in split plot in the field. Plants were harvested at full-flowering stage with dry matter content about 220 g/kg for first cutting and 260 g/kg for second cutting. Harvested plants were chopped theoretically into 2 to 3 cm lengths for ensiling. Chopped fresh materials were ensilaged by compressing in 2 L plastic jars about 3±0.1 kg. Results: Effects of N doses on dry matter, neutral detergent fiber, acid detergent fiber, dry matter digestibility, relative feed value, crude protein, pH, ammonia nitrogen, lactic acid, acetic acid, and lactic acid/acetic acid were statistically significant while water soluble carbohydrate, ash and organic matter were not statistically different. Ammonia nitrogen, crude protein, ash, organic matter, lactic acid, and lactic acid/acetic acid were affected by cultivars, but the other parameters were not. Increasing nitrogen applications positively affected the chemical composition of annual ryegrass silage. The significant increase in protein content was remarkable, however, silage fermentation properties were adversely affected by the increasing nitrogen dose. Conclusion: It can be recommended 150 kg/ha nitrogen dose for annual ryegrass harvested at full blooming stage. Even though the silage fermentation properties of the used cultivars were similar, cv. Devis gave better results than the others in terms of silage pH and relative feed value.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.4
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• pp.593-598
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• 2011

This research was performed to determine the quality characteristics of steamed bread by the number of times through the fermentation process. The number of fermentations varied from 1 to 5 while the steamed bread was prepared by measuring the duration of fermentation, and samples were analyzed in terms of general ingredients, physical properties, in vitro starch hydrolysis, protein digestibility, and sensory characteristics. Five times of fermentation resulted in significantly higher water content (p<0.01), and single fermentation led to the highest protein content (p<0.01). Protein levels decreased as fermentation was repeated. Single fermentation gave the lowest specific bread volume (p<0.05) and it increased with the number of fermentation times. Physical properties also varied with the number of times of fermentation. With more fermentation, hardness, gumminess, and chewiness decreased (p<0.01), whereas resilience (p<0.01) and cohesiveness (p<0.05) increased. In vitro starch hydrolysis was higher with 5 times of fermentation than with single to 3 times of fermentation (p<0.05). Protein digestibility was also higher with 5 times of fermentation (p<0.05). In sensory evaluations, whiteness scores were higher with 4 to 5 times of fermentation (p<0.01) whereas scores for crumb uniformity were lower with 4 and 5 times of fermentation. Moistness (p<0.01), cohesiveness (p<0.01), and chewiness (p<0.05) showed their highest scores with 4 times of fermentation.