• Korean Journal of Organic Agriculture
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• v.22 no.3
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• pp.469-481
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• 2014

IIn vitro antimicrobial and anti-inflammatory activities of nargenicin and its derivatives were investigated. Nargenicin, an unusual macrolide antibiotic with potent anti-MRSA (methicilin-resistant Staphylococcus aureus) activity, was purified from the culture broth of Nocardia sp. CS682. And variety of novel nargenicin derivatives was synthesized from nargenicin. Two compounds (4 and 5) exhibit a broad spectrum of antimicrobial activities against infectious bacteria. The antimicrobial activity of derivatives against fifteen organisms was assessed using the minimum inhibitory concentration (MIC). The MIC values were in the ranges of $0.15{\sim}80{\mu}g/mL$ (w/v) for compound 1 and 2, $5{\sim}80{\mu}g/mL$ (w/v) for compound 3, $1.25{\sim}40{\mu}g/mL$ (w/v) for compound 4, and $1.25{\sim}80{\mu}g/mL$ (w/v) for compound 5, depending on the pathogens studied. In vitro, we investigated cytotoxicity and inhibition of nitric oxide (NO) production of synthesized compounds 1-5 in Raw 264.7 cells. LPS-induced nitric oxide releases were significantly blocked by compound 3, 4 and 5 in a dose-dependent manner. At high concentrations ($5{\mu}g/mL$) compound 5 inhibited the NO production by 95%. Compound 4 inhibited the release of NO in LPS-activated Raw 264.7 cells by 75% at the concentration of $10{\mu}g/mL$. Compound 3 inhibited the release of NO in LPS-activated Raw 264.7 cells by 65% at the concentration of $100{\mu}g/mL$. On the other hand, nargenicin, compound 1 and 2 did not inhibit NO production. These results demonstrated that compound 4 and 5 displayed antimicrobial activity and blocked LPS-induced pro-inflammatory mediators such as NO in macrophages, which might be responsible for its therapeutic application.

• Korean Journal of Food Science and Technology
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• v.42 no.2
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• pp.125-129
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• 2010

Isoflavone distribution and $\beta$-glucosidase activity in 16 commercially available doenjang samples were determined. Twelve of the samples were home-made doenjang (HMD) with a relatively long fermentation period and 4 of the samples were factory-produced doenjang (FPD) from four different manufactures. Total isoflavones (TI) in the HMD ranged from $370-723\;{\mu}g/g$, while those in FPD ranged from $179-537\;{\mu}g/g$. The isoflavone distribution in HMD was different from those in FPD. Generally, the TI in HMD was higher than those in FPD. The major isoflavone was aglycones, which ranged from 42.98 to 89.96% in HMD and from 35.51 to 93.48% in FPD. Isoflavones in the $\beta$-glucoside forms were not detected in tested FPD samples. Principal components analysis (PCA) of the isoflavone profiles showed that HMD were differentiated from FPD. First principal component (PC1) and second principal component (PC2) expressed 43.6 and 22.9% of the data variability, respectively. $\beta$-Glucosidase activity in doenjang was lower than that in raw soybeans. The results of this study can be used to understand the differences in the isoflavone distribution in traditionally manufactured and factory produced doenjang.

• Food Science of Animal Resources
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• v.29 no.6
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• pp.659-667
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• 2009

Casein is considered to be the main source of protein in milk; therefore, many studies have been conducted to identify casein-derived bioactive peptides and their physiological effects. Casein is inactive within the parent protein but can be liberated by various proteases and enzymatic hydrolysis during microbial fermentation and gastrointestinal digestion. Once absorbed, casein exhibits different bioavailabilities in the body. Specifically, casein-derived peptides function as angiotensin converting enzyme (ACE) inhibitor in the cardiovascular system; thus, they are expected to reduce and prevent hypertension. Additionally, casein-derived peptides behave as opioid-like peptides in the nervous system, which impacts relaxation. These peptides are also expected to modulate various aspects of immune functions. Finally, caseinophosphopeptide (CPP) and glycomacropeptide (GMP) may exhibit a number of nutritional effects such as the absorption of calcium, iron or zinc. Many studies have been conducted to evaluate casein-derived peptides due to their multifunctional properties and the results of these studies have contributed to the development of a wide variety of functional dairy products. The purpose of this paper was to review the generation of bioactive peptides, their absorption and metabolism, and their specific bioactive effects.

• Food Engineering Progress
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• v.13 no.2
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• pp.110-116
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• 2009

Gochujang, a fermented traditional Korean hot pepper-soybean paste, has long been used to provide hot, sweet, and savory tastes. Changes in the pH, titratable acidity, moisture content, water activity, amino-nitrogen content, NaCl content, color, and yeast population during aging were investigated using a model system of Gochujang incorporated with strawberry puree up to 14% as a value-added food ingredient. pH decreased slowly till 60 days of aging then increased afterwards. Titratable acidity, on the other hand, increased during aging, reaching at the highest level at the 60 days of aging and then decreased rapidly. The moisture content continually increased during aging up to 90 days whereas water activity decreased rapidly till 60 days of aging and then slightly increased. The amino-nitrogen content increased while NaCl content decreased continually during aging. All the color parameters including L$^{*}$, a$^{*}$, and b$^{*}$-values increased during aging in general with exception for b$^{*}$-values in some conditions. Initial yeast population was ranged 1.2-4.9${\times}10^{6}$CFU/g and increased to 1.1-5.9${\times}10^{7}$CFU/g after 90 days of aging.

• Journal of the Korea Convergence Society
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• v.12 no.9
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• pp.185-191
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• 2021

In our study, we evaluated possibility of distillation process introduction for Korean Rubus coreanus balsamic vinegar production development, has a less complicated and more rapid process leading to higher production volumes and cost savings. In order to investigate the applicability of concentrated vinegar fraction (CVF) and distilled vinegar fraction (DVF) obtained from the distillation process as balsamic and distillation vinegar, acidity, pH, and specific gravity (S.G.) were measured for the vinegar fraction obtained from the distillation process. The acidity of final CVF (60% of initial volume) obtained 4 types of vinegar (acidity; 4.42, 4.84, 5.61, and 6.35) were increased mean 38.1%, compared to initial acidities. Especially, acidity and pH of the final CVF was similar to balsamic vinegar. In addition, acidity of DVF also increased and it of the final fraction was 4.41%, 4.95%, 5.88%, and 6.72%, respectively. And it was suggested that the final DVF could be used as distilled vinegar. In this study, it was confirmed that vinegar can be effectively concentrated through the distillation process, and distilled vinegar can be produced at the same time. However, it is thought that the introduction of the distillation process can be decided only after additional biochemical characteristics such as organic acid content and antioxidant activity measurement for each vinegar fraction are analyzed.

• Food Science and Industry
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• v.51 no.4
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• pp.302-312
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• 2018

Bioactive peptides generated from milk proteins play an important role in the prevention and alleviation of diabetes. Whey proteins possess direct insulinotropic effect by amino acids (especially branch chain amino acids) produced through its gastrointestinal digestion. Additionally, blood glucose level can be lowered by gut hormone which called incretin [glucose dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1)]. However, physiological effects of incretin readily disappeared by dipeptidyl peptidase-4 (DPP-4) causing degradation of GLP-1. Several DPP-4 inhibitors are currently used as therapeutic medicines for the treatment of type II diabetes. More than 60 natural peptide (2-14 amino acids) DPP-4 inhibitors were identified in milk proteins. Peptide DPP-4 inhibitors act as substrate inhibitor and delay breakdown of GLP-1 both in vitro and in vivo. This review summarizes nutritional quality of milk proteins, absorption and mode of action of bioactive peptides, and finally up-to-dated knowledge on DPP-4 inhibitory peptides derived from milk proteins.

• Food Science and Industry
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• v.53 no.1
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• pp.69-83
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• 2020

For the development of the chitosan industry in Korea, the catch of red snow crabs caught on the east coast is rapidly decreasing. Therefore, it is urgent to develop raw materials that can replace the red snow crab as the top priority to solve the supply and demand problems, as well as wastewater treatment costs account for a large proportion of the cost of chitosan. In order to solve the problems, continuous research on biological extraction methods such as enzymatic extraction and microbial fermentation will increase production efficiency and lower unit cost as well as chemical extraction methods. Further efficient manufacturing method can be established. Establishing of novel techniques is indispensable for production of high-purity chitosan and the ability to regulate and separate the molecular weight, as well as joint research with industry, academia and research institute for the research and development of high-functional chitosan derivatives.

• Journal of Food Hygiene and Safety
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• v.37 no.2
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• pp.107-113
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• 2022

A number of studies have been conducted to confirm the preventive effect of xylitol on dental caries as a whole or partial alternative to dietary sugars. This study reviewed the oral health effects of xylitol on the prevention mechanism of dental caries, the prevention of dental caries, the inhibition of mother-to-child transmission, and the oral health effects in the elderly based on existing studies on the oral health of xylitol. Carbohydrates and dietary sugars in food are fermented by acid-producing microorganisms in the mouth and produce dental plaque and acid, which cause dental caries. However, most dental decay-causing bacteria cannot produce acids by metabolizing xylitol. Xylitol, stored in cells as a non-metabolizable metabolite by Streptococcus mutans (S. mutans), affects bacterial glucose metabolism and inhibits bacterial growth. Xylitol consumption also reduces the amount of plaque and the population of S. mutans in both plaque and saliva. In addition, xylitol acts in the remineralization process. Xylitol has been confirmed to effectively prevent dental caries, inhibit mother-to-child transmission of MS, prevent dental caries, and increase salivary flow in the elderly. In conclusion, xylitol is an adequate sugar substitute for dental health, from infants to the elderly. For future studies, the researchers recommend reviewing the effects of xylitol on the oral and intestinal microbial environment and the side effects of excessive intake.

• Journal of Life Science
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• v.31 no.11
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• pp.1046-1055
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• 2021

Vanillin is the primary flavor and fragrance compound of natural vanilla and is extensively used in the food, beverage, perfumery, pharmaceutical industries, and other applications. Vanillin can be produced by chemical synthesis, extraction from vanilla plants, microbial bioconversion of natural precursors to vanillin, and direct fermentation using glucose. Currently, most commercially available vanillin is produced by extraction from cured vanilla pods and by chemical synthesis using guaiacol and glyoxylic acid as starting raw materials. Due to environmental issues, health complaints, preference for natural sources, and the limited supply and soaring price of natural vanilla, biotechnology-based vanillin production is regarded as a promising alternative. As many microorganisms that are able to metabolize several natural precursors, including ferulic acid, eugenol, isoeugenol, and lignin, and accumulate vanillin, have been screened and evaluated, myriad strategies and efforts have been employed for the development of commercially viable production technology. This review outlines the recent advances in the biotechnological production of natural vanillin with the use of these natural precursors. Moreover, it highlights the recent engineering approaches for the production of natural vanillin from renewable carbon sources based on the de novo biosynthetic pathway of vanillin from glucose, together with appropriate solution strategies to overcome the challenges posed to increase production titers.

• Korean Journal of Organic Agriculture
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• v.29 no.4
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• pp.613-623
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• 2021

This study was conducted to investigate the effect of addition levels of coffee and green tea by products extract including polyphenols through hot water extraction on rumen fermentation. The treatment groups consisted of coffee extract (CO), green tea extract (GR) and mixed extract (MIX), and the addition level was 10 µL, 20 µL and 30 µL of three levels. The experiment consisted of a total of 10 experimental groups including the control group, and a full factorial design was used. The effect of polyphenol addition in coffee and green tea by-products was analyzed through main and interaction effect of statistical analysis. The total polyphenol content of the extracts was 106.15, 79.10 and 185.25 ㎍ GAE/g DM for coffee by-product, green tea by-product and mixture, respectively. Total gas production was significantly lower in the treatment groups than in the control (114.00 mL/gDM) (p<0.05). Methane emission tended to decrease as the polyphenol addition level increased. Moreover, the MIX showed the lowest methane emission when 30 µL was added (p<0.05). Volatile fatty acids showed a significant difference compared to the treatment group as a control (98.06 mM) (p<0.05), but there was no change according to the level of polyphenols. As a result of the main effect and interaction, it is thought that the effect on methane reduction and improvement of rumen fermentation in MIX20 can be expected. In a series of studies, the addition of 20 µL of a blended extract of coffee and green tea by-products is thought to reduce methane to levels that do not inhibit rumen fermentation.