• Journal of Dairy Science and Biotechnology
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• v.41 no.1
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• pp.34-43
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• 2023

Hydrolysis of whey-derived proteins using lactic acid bacteria (LAB) utilizes the mass culture method and fermentation of LAB to produce effective bioactive peptides. Whey protein has the biological potential of its precursors, but the active fragments may not be released depending on the hydrolysis method. As an alternative to these problems, the nutritional and bioactive functionality of the hydrolysis method have been reported to be improved using LAB for whey protein. Peptide fractions were obtained using a sample fast protein liquid chromatography device. Antioxidant activity was verified for each of the five fractions obtained. In vitro cell experiments showed no cytotoxicity and inhibited nitric oxide production. Cytokine (IL [interleukin]-1α, IL-6, tumor necrosis factor-α) production was significantly lower than that of lipopolysaccharides (+). As a result of checking the amino acid content ratio of the fractions selected through the AccQ-Tag system, 17 types of amino acids were identified, and the content of isoleucine, an essential amino acid, was the highest. These properties show their applicability for the production of functional products utilizing dietary supplements and milk. It can be presented as an efficient method in terms of product functionality in the production of uniform-quality whey-derived peptides.

• Microbiology and Biotechnology Letters
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• v.52 no.2
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• pp.122-134
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• 2024

Levan is a functional fructooligosaccharide that belongs to the class of fructans and displays a range of physiological and dietary benefits. Levansucrase, classified as a fructosyltransferase, catalyzes the synthesis of levan fructans through the transfer of d-fructosyl residues from sucrose. Recombinant levansucrase exhibits a significantly high level of expression and activity in E. coli, however, its industrial applicability is limited due to its relatively poor thermal stability. In this study, we generated six single mutants by targeting either the high flexibility regions (242-250) or the 382Glu residue within the -TEAP- motif, and further developed two double mutants featuring concurrent mutations encompassing both regions. We expressed multiple levansucrase mutant proteins in E. coli DH5α using site-directed mutagenesis and measured the enzymatic activity and thermal stability of each mutant by levan formation reactions. The E246Y mutant displayed half-time 5.02-fold and 1.89-fold higher at 55℃ and 56℃, respectively, when compared to the WT, whereas the E382L mutant exhibited a 1.06-fold enhancement in half-time at 55℃. Furthermore, E246Y/E382L exhibited 1.95-fold and 1.86-fold higher thermal stability at 55℃ and 56℃, respectively. These findings suggest the potential for the developed thermally stable levansucrases to be applied in industrial settings, highlighting the effectiveness of our targeted mutagenesis approach.

• Korean Journal of Poultry Science
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• v.40 no.1
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• pp.31-40
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• 2013

This study was performed to investigate the investigated effects of dietary supplementation of vitamin C and E on the growth performance and stress response in broiler chickens. Stress response was analyzed by the quantity of telomeric DNA, the rate of DNA damage and the expression levels of heat shock proteins (HSPs) and hydroxyl-3-methyl-glutaryl coenzyme A reductase (HMGCR) genes on tissues and blood. The telomere length and telomere shortening rates were analyzed by quantitative fluorescence in situ hybridization on the nuclei of lymphocytes and tissues. The DNA damage rate of lymphocytes was quantified by the comet assay. The expression levels of HSP70, HSP90s and HMGCR genes were measured by quantitative real-time polymerase chain reaction in lymphocytes. In results, there was no significant difference among treatments in body weight, weight gain, feed intake and mortality. The telomere shortening rate of the lymphocytes was significantly lower in the vitamin E supplemented group than the control group. The DNA damage was also decreased supplemented with vitamin C and E, as compared to the control group. The vitamin E supplemented group had a significant positive effect on the expressions of HMGCR, HSP90-${\alpha}$ and HSP90-${\beta}$ in lymphocytes, but had no significance on HSP70, as compared to the control group. We concluded that the dietary supplementation of vitamin E (100 mg/kg feed) had reduced the individual physiological stress response without stunt growth in broiler chickens.

• Korean Journal of Ichthyology
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• v.32 no.2
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• pp.70-77
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• 2020

A feeding experiment was conducted to investigate the effects of replacement of dietary fish meal by frozen whole krill (FWK) and/or krill meal (KM) on growth performance and body composition of juvenile black rockfish, Sebastes schlegeli. The basal experimental diet (ED) contained 58.4% fish meal (FM) as a control, the other five EDs were formulated with the protein replacement ratio of fish meal by as 0, 10, 20, 30, and 40%, respectively (FWKM0, FWK10, FWK20, FWK20KM10, FWK20KM20 and FWK20KM20HP). Each diet was fed to juvenile rockfish initially weighing 3.09±0.02 g/fish in a flow-through system. The control ED containing 58.4% FM and 10% FWK diet showed significantly higher weight gain and feed efficiency than all the other EDs containing 20, 30, and 40% FWK and/or KM. But the survivals, whole-body moistures, crude proteins and lipids of black rockfish fed all EDs were similar in all EDs. The only whole-body ashes of juvenile black rockfish were significantly differentiated by feeding the various EDs containing different levels of FWK and/or KM with a protein and lipid levels adjustment. These results suggest that dietary frozen whole Antarctic krill and/or krill meal inclusions could not improve the growth but change the whole-body ashes in juvenile black rockfish. Therefore, this study further indicates that dietary more than 20% of FWK and/or KM supplementation could not be a potential source of animal protein to replace fishmeal in juvenile black rockfish.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.10
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• pp.1446-1458
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• 2013

The study assessed the effect of dietary supplementation of leaf meal mixture (LMM) containing condensed tannins (CT) on feed intake, nutrient utilization and performance of sheep infected with Haemonchus contortus. Eighteen adult sheep of similar age and body weight ($25.03{\pm}1.52$) were included in this study and out of these, 12 sheep were infected with single dose of infective third stage larvae of H. contortus at 2,000 larvae per sheep. The experimental sheep were allocated in three different groups' i.e. negative control (NC; no infection), control (C; H. contortus infected) and treatment (T; H. contortus infected+CT at 1.5% of the DM through LMM) and the experiment was conducted for a period of 90 d. The intake of dry matter (DM), organic matter (OM) and digestibility of DM, OM, neutral detergent fibre (NDF) and acid detergent fibre (ADF) were comparable among three animal groups. However, digestibility of crude protein (CP) and ether extract (EE) were significantly (p<0.05) higher in NC group as compared to both C and T groups. Nitrogen (N) retention (g/d or % of N intake) was significantly (p = 0.038) lower in C group as compared to T and NC groups. Daily intake (g/kg $W^{0.75}$) of digestible crude protein (DCP), digestible organic matter (DOM) and total digestible nutrient (TDN) did not differ significantly (p<0.05) in the three groups. Haemoglobin (Hb) and packed cell volume (PCV) were significantly (p<0.001) higher in treatment group as compared to control. The level of Hb and PCV reduced (p<0.001) after 30 days of experimental feeding. CT significantly (p<0.001) reduced serum urea in T group as compared to NC and C groups. Serum proteins differed significantly (p<0.01) among the three groups. The activity of serum enzymes AST, ALT, ALP and LDH were also statistically non significant (p<0.05) among treatments. The weight of abomasal lymph nodes (ALN) in T group was higher (p<0.05) than in C group. Treatment group had lower (p<0.05) total worms and fecal egg count compared to control group. It may be concluded that dietary supplementation of CT through LMM significantly improved the N retention, and inhibited the different developmental stages of Haemonchus contortus in experimental sheep.

• Korean Journal of Community Nutrition
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• v.24 no.2
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• pp.152-162
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• 2019

Objectives: The purpose of this study was to investigate the food, nutrient intake, and diet quality of postmenopausal women at high risk of osteoporosis (OP) and cardiovascular disease (CVD) compared with those of control subjects. Methods: A total of 1,131 post-menopausal women aged over 45 years, who took the 2010-2011 Korean National Health and Nutrition Examination Survey (KNHANES), were included for analysis. These participants were classified into the following groups: the OP group, with a risk of OP (n=135); the CVD group, with a risk of CVD (n=373); the OP+CVD group, with a risk of OP and CVD concurrently (n=218); and the control group (n=405) according to bone mineral density (BMD) and CVD risk. Anthropometric measurements, blood profiles, dietary intake, and dietary quality indices were measured and compared among the four groups. Results: Waist circumference, total body fat percentage, blood pressure, fasting plasma glucose, total cholesterol, triglyceride, and LDL-cholesterol were higher, and HDL-cholesterol and BMD were lower in the OP+CVD group than in the control group. In the food frequency questionnaire, the OP+CVD group had significantly higher frequencies of grain (except for multi-grain) and lower frequencies of fruit and dairy product. The frequency of consumption of red meat, processed meat, and carbonated beverages was higher in OP+CVD group. In nutrient density analysis, proteins and vitamin $B_2$ levels were significantly lower in the OP+CVD group than in the control group. The nutritional quality index (INQ) values of calcium were in the order of 0.63, 0.58, 0.56, and 0.55 in each group, and it was urgent to improve the dietary intake for calcium in postmenopausal women. In addition, vitamin $B_2$ was inadequately consumed by all groups. Conclusions: These results suggest that it is necessary to increase the intake of vitamin $B_2$ and calcium and decrease the frequency of intake of red meat, processed meat, and carbonated beverages in postmenopausal women with the risk of OP and CVD.

• Korean Journal of Exercise Nutrition
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• v.13 no.1
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• pp.1-7
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• 2009

It has been shown that both caloric restriction and exercise, enhances glucose uptake through translocation of GLUT-4 protein. It remains unclear how exercise and caloric restriction affect the changes in VAMP (vesicle-associated membrane protein) in skeletal muscle and GLUT-2 in liver. This study investigated the effects of exercise training and caloric restriction on the expressions of glucose transport relating proteins in muscle and liver tissues in diabetic rats. Forty male Sprague-Dawley rats (250±10 g; 8 week in age) were assigned equally to four different groups; control (C), exercise only (E), dietary restriction only (D) and dietary restriction and exercise (DE). Daily food consumption was monitored to establish baseline intake. Both C and E groups consumed baseline food intake while D and DE groups were provided with only 60% of baseline total food intake. Forty-eight hours after intraperitoneal injection of STZ (50 mg/kg), diabetes was confirmed (8-hr fasting blood glucose levels ≥300 mg/dl). Rats in the E and DE groups exercised on a motorized treadmill for 30 min/d, 5 days/week for 4 weeks (5 min running at 3 m/min, 0% grade; 8 m/min for the next 5min, and then 15 m/min for 20 min). Rats were sacrificed 48 hrs after the last bout of exercise. Soleus muscle and liver were extracted to analyze for GLUT-4, VAMP-2, and GLUT-2, respectively. All variables were analyzed using the Western Blotting technique. All values were expressed as optical volume measured by optical density. A Two-way ANOVA was used to examine the difference between groups and applied Duncan's test for post-hoc. No significant differences in GLUT-2 expression were found among groups. However, E (280133±13228 arbitrary units{AU}) and DE (268833±14424 AU) groups showed significantly higher (p<.001) levels of GLUT-4 as compared with C (34461±2099 AU) and D groups (27847±703 AU). VAMP-2 protein expression increased (p<.001) in E (184137±7803 AU) and DE (189800±10856 AU) groups as compared to C (74201±8296AU) and D (72967±863 AU) groups. These results suggest that either exercise with or without caloric restriction increases the up-regulation of GLUT-4 and VAMP-2 in skeletal muscle of diabetic rats. However, GLUT-2 protein in liver was not affected by either exercise or exercise with caloric restriction.

• Korean Journal of Poultry Science
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• v.43 no.1
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• pp.47-54
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• 2016

The aim of this study was to investigate the expression patterns of key genes involved in lipid metabolism in response to dietary Coenzyme Q10 (CoQ10) in hens. A total of 36 forty week-old Lohmann Brown were randomly allocated into 3 groups consisting of 4 replicates of 3 birds. Laying hens were subjected to one of following treatments: Control (BD, basal diet), T1 (BD+ CoQ10 100 mg/kg diet) and T2 (BD+ micellar of CoQ10 100 mg/kg diet). Birds were fed ad libitum a basal diet or the basal diet supplemented with CoQ10 for 5 weeks. Total RNA was extracted from the liver for quantitative RT-PCR. The mRNA levels of HMG-CoA reductase(HMGCR) and sterol regulatory element-binding proteins(SREBP)2 were decreased more than 30~50% in the liver of birds fed a basal diet supplemented with CoQ10 (p<0.05). These findings suggest that dietary CoQ10 can reduce cholesterol levels by the suppression of the hepatic HMGCR and SREBP2 genes. The gene expressions of liver X receptor (LXR) and SREBP1 were down regulated due to the addition of CoQ10 to the feed (p<0.05). The homeostasis of cholesterol can be regulated by LXR and SREBP1 in cholesterol-low-conditions. The supplement of CoQ10 caused a decreased expression of lipid metabolism-related genes including $PPAR{\gamma}$, XBP1, FASN, and GLUTs in the liver of birds (p<0.05). These data suggest that CoQ10 might be used as a dietary supplement to reduce cholesterol levels and to regulate lipid homeostasis in laying hens.

• Journal of Nutrition and Health
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• v.46 no.3
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• pp.261-275
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• 2013

This study was designed to investigate the relationships of depressed mood with obesity, blood and urinary compositions, and dietary habits in Koreans at the age of 40, a critical transition to the middle adulthood stage. A total of 27,684 people who have taken the Life Transition Period Health Examination at the Korea Association of Health Promotion in 2011 were divided into two groups; the depressed mood group (DG) and the non-depressed group (NG) according to results of the primary questionnaire for mental health. The results were analyzed using the health examination criteria of the National Health Insurance Corporation. Women and medicaid recipients showed higher incidence of depressed mood than men and health insurance subscribers. People with underweight in BMI or abdominal obesity showed correlation with depressed mood, while there was no significant relationship with metabolic syndrome. Regarding blood and urinary compositions, DG was related to a higher level of hemoglobin and lower levels of HDL-cholesterol and triglyceride, although the relationships diminished after adjustment for other confounder effects. According to dietary habits, more people in DG were categorized as a group for "Needs Much Improvement", and the odds ratio of the depressed mood showed a significant increase. Significant difference regarding the frequency of food items such as milk products, animal proteins, Kimchi, and fruits was observed between DG and NG. In addition, a higher portion of subjects in DG did not consume regular meals and various kinds of food. In conclusion, the depressed mood of 40 year-old adults was significantly related to underweight, higher waist measurement, and undesirable dietary habits. Results of our study can be applicable as a basic resource for development of effective nutrition counseling and education programs for improvement of mental health promotion during the critical transition to the middle adulthood stage.

• Journal of Life Science
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• v.20 no.4
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• pp.528-534
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• 2010

Garlic (Allium sativum) has been well-known as a folk remedy for a variety of ailments since ancient times, and it is well documented that enhanced garlic consumption leads to a decrease in incidences of cancer. Tight junctions (TJs) are critical structures for the maintenance of cellular polarity, acting as paracellular permeability barriers and playing an essential role in regulating the diffusion of fluid, electrolytes and macromolecules through the paracellular pathway. Matrix metalloproteinases (MMPs) have been implicated as possible mediators of invasiveness and metastasis in some cancers. In this study, we investigated the potential effects of water extract of aged black garlic (ABG) on the correlation between tightening of TJs and anti-invasive activity in human gastric carcinoma AGS cells. The inhibitory effects of ABG on cell motility and invasiveness were found to be associated with increased tightness of TJs, which was demonstrated by an increase in transepithelial electrical resistance. Additionally, the activities of MMP-2 and -9 in AGS cells were inhibited by treatment with ABG, and this was also correlated with a decrease in the expression of their mRNA and proteins. Furthermore, RT-PCR and immunoblotting results indicated that ABG repressed the levels of the claudin proteins, major components of TJs that play a key role in the control and selectivity of paracellular transport. In conclusion, these results suggest that ABG treatment may inhibit tumor metastasis and invasion, and therefore may act as a dietary source to decrease the risk of developing cancer.