• Food Science of Animal Resources
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• v.29 no.4
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• pp.437-444
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• 2009

${\gamma}-Aminobutyric$ acid (GABA) producing lactic acid bacteria, Lactobacillus acidophilus RMK567 was cultivated in 50 L of sterilized MRS broth using a fermenter at $40^{\circ}C$ for 24 h. The cell number was increased to $10.04{\pm}0.13$ Log CFU/mL with a growth rate constant (k) of 0.454 generation/h and a generation time (g) of 2.303 h after a lapse of a lag phase (L) of 5.16 h. A total of 487 g of cell paste with 40.5% moisture was harvested with viable cell number of 12.48 Log CFU/g cell paste. The cell pastes after preparation with glycerol, glucose, and polydextrose as cryo-protectants were lyophilized under a vacuum of 84 m torr. A total of 408 g of freeze dried (FD) cell powders were mixed with a commercial strain of Streptococcus thermophilus to prepare of three types FD starter cultures with the viable cell numbers of 12.42 (FDA-GY), 12.60 (FDBGG) and 12.91 (FDC-GP) Log CFU/g. During preservation the FD cultures at -$18^{\circ}C$, the cell viability of the FD starter cultures were rapidly dropped to below 3.24% of the day of storage. No significant difference was found in the cell viabilities among three types of FD starters cultures, but significant difference (p<0.01) was found in storage periods. Yoghurts fermented through FD starter culture of L. acidophilus RMK567 were determined to contain $155.16{\pm}8.53$ ppm, $243.82{\pm}4.27$ ppm, and $198.64{\pm}23.46$ ppm of GABA, respectively. This study shows that GABA production activity of L. acidophilus RMK567 is not affected during the freeze drying process and would be available for commercial production of yoghurt containing high GABA content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.7
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• pp.839-845
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• 2009

Colorectal cancer is the third most common malignant neoplasm in the world. Much attention has been focused on reducing colon cancer risk through medical properties of natural compound that could act as anticarcinogens. In this study, we evaluated the antioxidant and antigenotoxic effects of Styela plicata (S. plicata) from in vitro experiments. S. plicata extracts showed antioxidant activity measured by TRAP assay and antigenotoxic effect in $200{\mu}M$ $H_2O_2$ induced DNA damage in human leukocytes. Especially, freeze-dried S. plicata extracted with methanol showed the highest level of TRAP (0.225 mM) and inhibition of DNA damage (66.8%). Additionally we observed the effect of S. plicata on the formation of aberrant crypt foci (ACF) induced by dimethylhydrazine (DMH) and DMH induced DNA damage (by comet assay) in male SD rats. The animals were divided into three groups and fed high-fat and low fiber diet (100 g lard+20 g cellulose/kg diet) without (normal control and DMH control) or with a 3% (w/w) of lyophilized S. plicata powder (DMH+S. plicata). One week after beginning the diets, rats were treated with DMH (30 mg/kg, s.c.) for 6 weeks except for normal control group, which was treated saline instead; dietary treatments were continued for the entire experiment. Nine weeks after DMH injection, administration of S. plicata resulted in reduction of ACF numbers, to 82.7% of the carcinogen control value ($7.67{\pm}2.04$ vs. $1.33{\pm}0.53$: p<0.01). S. plicata supplementation induced antigenotoxic effect on DMH-induced DNA damage in the blood cell (% tail intensity: $6.79{\pm}0.26$ vs. $6.13{\pm}0.22$). These data indicate that S. plicata extract has antigenotoxic and anticarcinogenic effects from in vitro experiments and S. plicata exerts a protective effect on the process of colon carcinogenesis, possibly by suppressing the DMH-induced DNA damage in blood cell and the development of preneoplastic lesions in colon.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.4
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• pp.435-441
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• 2017

The present study was carried out to evaluate the applicability of Tenebrio molitor larvae (mealworm) as a health functional food material in order to contribute to the development of the domestic insect industry and health functional food industry. Protein hydrolysates were prepared from mealworm powder by enzymatic hydrolysis using five different proteases (alcalase, bromelain, flavourzyme, neutrase, and papain), and the hydrolysates were then tested for their antioxidant activities. Based on available amino group contents and sodium dodecyl sulphate-polyacrylamide gel electrophoresis analyses, mealworms treated with alcalase ($4,781.39{\mu}g/mL$), flavourzyme ($5,429.35{\mu}g/mL$), or neutrase ($3,155.55{\mu}g/mL$) for 24 h showed high degree of hydrolysis (HD) value, whereas HD values of bromelain ($1,800{\mu}g/mL$) and papain-treated ($1,782.61{\mu}g/mL$) mealworms were much lower. Protein hydrolysates showing high HD values were further separated into > 3 kDa and ${\leq}3kDa$ fractions by a centrifugal filter system and then lyophilized, and the production yields of the low molecular weight protein hydrolysates (${\leq}3kDa$) by alcalase, flavourzyme, and neutrase were 42.05%, 26.27%, and 30.01%, respectively. According to the RC_{50} values of the protein hydrolysates (${\leq}3kDa$) obtained from three different antioxidant analyses, all three hydrolysates showed similar antioxidant activities. Thus, alcalase hydrolysates showing the highest production yield of low molecular weight protein hydrolysates were further tested for their inhibitory effects on peroxidation of linoleic acid by measuring thiobarbituric acid values, and the results show that peroxidation of untreated linoleic acid increased dramatically during 6 days of incubation. However, pretreatment with the hydrolysates ($100{\sim}800{\mu}g/mL$) significantly inhibited linoleic acid peroxidation in a dose-dependent manner over 6 days.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.10
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• pp.1164-1170
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• 2017

Protaetia brevitarsis larvae (PBL) has recently been registered as a temporary food in Korea, and this study evaluated the application potential of PBL proteins as health functional food materials. Protein hydrolysates were prepared from PBL powder by enzymatic hydrolysis using five different proteases (alcalase, bromelain, flavourzyme, neutrase, and papain), and based on the results from the peptide content and SDS-PAGE analyses, PBL treated with alcalase or flavourzyme showed a high degree of hydrolysis (HD) value, whereas the HD value of those treated with neutrase, bromelain, or papain was minimal. The protein hydrolysates showing a high HD value were separated further into the fractions of >3 kDa and <3 kDa by a centrifugal filter system and then lyophilized, and according to the $RC_{50}$ values of the protein hydrolysates (<3 kDa) obtained from three different antioxidant analyses; the alcalase hydrolysates showed the highest antioxidant activity. Therefore, the alcalase hydrolysates were tested further for their inhibitory effects on the peroxidation of linoleic acid by measuring the thiobarbituric acid values. The results showed that the peroxidation of untreated linoleic acid increased dramatically during 6 days of incubation, but a pretreatment with the hydrolysates ($100{\sim}800{\mu}g/mL$) significantly inhibited the linoleic acid peroxidation in a dose-dependent manner for 6 days. Our current studies are focused on the identification of active peptide sequences from alcalase hydrolysates.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.3
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• pp.211-221
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• 2017

This study was performed to investigate the functional properties and characteristics of Dolnamul (Sedum sarmentosum) as a cosmetic ingredient. Lyophilized sedum powder was extracted with ethanol and stored at $-20^{\circ}C$ for the following experiments. Total polyphenol compounds of the ethanol extract of sedum (SE) was $27.98{\pm}0.34g/kg$(dry weight): epicatechin ($162.14{\pm}5.07mg/kg$), epigallocatechin ($55.99{\pm}2.49mg/kg$), and kaempferol ($47.96{\pm}3.02mg/kg$) were contained in the SE. The SE had organic radical scavenging capacity ($78.43{\pm}1.08%$) and metal reducing power (FRAP value $2.54{\pm}0.12$). FTC and TBARS assays confirmed that the SE inhibited the early stage of lipid peroxidation ($62.03{\pm}0.38%$) as well as the final stage of lipid peroxidation ($55.36{\pm}2.05%$), respectively. The SE (5 mg/mL, dry weight) was proved to have antibacterial effect on the growth of Propionibacterium acnes. The inhibitory percentages of the SE on elastase and collagenase activities were $38.94{\pm}7.09%$ and $78.94{\pm}2.49%$, respectively. Compare to the control group, the SE treated group induced an increase of Col3A1 expression and collagen production ($58.11{\pm}1.07%$). The oil in water emulsion (0.5% SE adding group) showed pH 6.88 and 1.47 g/mL of density. The hardness changes of the SE adding emulsions were not detected during the stored periods at various temperatures ($-20-45^{\circ}C$) for four weeks. It is considered that the SE has antibacterial, antioxidant, and antiaging activities.