Song Hwan Bae

Preparation of angiotensin I converting enzyme inhibitor from corn gluten

Hydrolysates were prepared from corn gluten containing powerful angiotensin I converting enzyme (ACE) inhibitory activity with low bitterness. Among six commercial proteases, Flavourzyme showed the highest ACE inhibitory activity (IC50: 0.18 mg solid). Flavourzyme (complex type), Pescalase (endo-type), and Protease A (exo-type) were used to evaluate corn gluten hydrolysates according to the enzyme specificity. ACE inhibitory activities of the hydrolysates had the same trend as protein content. Flavourzyme and Pescalase showed high ACE inhibitory activity (IC50: 0.18 mg solid and IC50: 0.17 mg solid, respectively) after 8 and 1 h of hydrolysis, respectively. However, Protease A showed no changes of ACE inhibitory activity after 1 h of hydrolysis. A mixture of Pescalase and Protease A (1:1, w/w) was applied to the preparation of corn gluten hydrolysate. The hydrolysis time using the enzyme mixture was reduced from 8 to 4 h compared with Flavourzyme. Surface hydrophobicity of the hydrolysate with the enzyme mixture was lower than that of the hydrolysate with Flavourzyme, but there was no significant difference at P<0.05. Average hydrophobicity (Q value) of the hydrolysates with the Flavourzyme and the enzyme mixture was to be less than 1400 kcal/mol. It was assumed that there was no difference in bitterness between the hydrolysate with Flavourzyme and that with the enzyme mixture.

The bioavailability of red ginseng extract fermented by Phellinus linteus.

For the improvement of ginsenoside bioavailability, the ginsenosides of fermented red ginseng by Phellinus linteus (FRG) were examined with respect to bioavailability and physiological activity. The polyphenol content of FRG (19.14±0.50 mg/g) was significantly higher (p<0.05) compared with that of non-fermented red ginseng (NFRG, 11.31±1.15 mg/g). The antioxidant activities in FRG, such as 2,2’-diphenyl-1-picrylhydrazyl, 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid, and ferric reducing antioxidant power, were significantly higher (p<0.05) than those in NFRG. The HPLC analysis results showed that the FRG had a high level of ginsenoside metabolites. The total ginsenoside contents in NFRG and FRG were 41.65±1.53 mg/g and 50.12±1.43 mg/g, respectively. However, FRG had a significantly higher content (33.90±0.97 mg/g) of ginsenoside metabolites (Rg3, Rg5, Rk1, compound K, Rh1, F2, and Rg2) compared with NFRG (14.75±0.46 mg/g). The skin permeability of FRG was higher than that of NFRG using Franz diffusion cell models. In particular, after 3 h, the skin permeability of FRG was significantly higher (p<0.05) than that of NFRG. Using a rat everted intestinal sac model, FRG showed a high transport level compared with NFRG after 1 h. FRG had dramatically improved bioavailability compared with NFRG as indicated by skin permeation and intestinal permeability. The significantly greater bioavailability of FRG may have been due to the transformation of its ginsenosides by fermentation to more easily absorbable forms (ginsenoside metabolites).

Changes of Ginsenoside Content by Mushroom Mycelial Fermentation in Red Ginseng Extract

To obtain microorganisms for the microbial conversion of ginsenosides in red ginseng extract (RGE), mushroom mycelia were used for the fermentation of RGE. After fermentation, total sugar contents and polyohenol contents of the RGEs fermented with various mushrooms were not a significant increase between RGE and the ferments. But uronic acid content was relatively higher in the fermented RGEs cultured with Lentus edodes (2155.6 μg/mL), Phelllinus linteus (1690.9 μg/mL) and Inonotus obliquus 26137 and 26147 (1549.5 and 1670.7 μg/mL) compared to the RGE (1307.1 μg/mL). The RGEs fermented by Ph. linteus, Cordyceps militaris, and Grifola frondosa showed particularly high levels of total ginsenosides (20018.1, 17501.6, and 16267.0 μg/mL, respectively). The ferments with C. militaris (6974.2 μg/mL), Ph. linteus (9109.2 μg/mL), and G. frondosa (7023.0 μg/mL) also showed high levels of metabolites (sum of compound K, Rh1, Rg5, Rk1, Rg3, and Rg2) compared to RGE (3615.9 μg/mL). Among four different RGE concentrations examined, a 20 brix concentration of RGE was favorable for the fermentation of Ph. linteus. Maximum biotransformation of ginsneoside metabolites (9395.5 μg/mL) was obtained after 5 days fermentation with Ph. linteus. Maximum mycelial growth of 2.6 mg/mL was achieved at 9 days, in which growth was not significantly different during 5 to 9 days fermentation. During fermentation of RGE by Ph. linteus in a 7 L fermenter, Rg3, Rg5, and Rk1 contents showed maximum concentrations after 5 days similar to flask fermentation. These results confirm that fermentation with Ph. linteus is very useful for preparing minor ginsenoside metabolites while being safe for foods.

Stimulation of osteoblastic differentiation and mineralization in MC3T3‐E1 cells by yeast hydrolysate

In a previous study, it was reported that yeast hydrolysate (YH) was effective in promoting bone growth in Sprague‐Dawley (SD) rats. To further clarify the mechanism of YH, the effects of YH on proliferation, differentiation and gene expression in vitro were investigated using osteoblastic cell lines (MC3T3‐E1). Cell proliferation increased significantly as much as 110% of the basal value when cells were treated with 100 µg/mL of YH. Alkaline phosphatase (ALP) activity increased significantly with a YH concentration of 25–100 µg/mL, and the activity increased 152% that of the control at 100 µg/mL. The calcium content increased as much as 129% at 100 µg/mL YH. The gene expression levels of ALP and collagen type II (COL II) significantly increased approximately 1.3‐fold and 1.7‐fold of control, respectively, at 100 µg/mL. YH increased significantly the mRNA level of bone sialoprotein (BSP) but not in a dose‐dependent manner. The mRNA levels of bone morphogenetic proteins (BMP)‐2, BMP‐4, collagen type I (COL I) and osteonectin (ON) did not increase. In summary, YH increased the proliferation of osteoblasts and directly stimulated ALP and bone matrix proteins (e.g. BSP, COL II), and these increases trigger osteoblastic differentiation (e.g. mineralized nodule formation). Copyright

Yeast hydrolysate induces longitudinal bone growth and growth hormone release in rats.

This study investigated the growth promoting effects of yeast extract (YH) fed to Sprague‐Dawley male rats (3 weeks old) for 4 weeks. The negative (N)‐control and positive (P)‐control groups were given a daily oral administration of saline and foremilk (1 g/kg of BW), respectively, and the YH‐1 and YH‐2 groups were given daily administrations of YH (0.5 and 1 g/kg of BW, respectively). After 4 weeks, the YH‐1, YH‐2 and P‐control groups showed significant differences in the body weight gain compared with the N‐control group (p < 0.05). The YH‐1 and YH‐2 groups also had significantly different tibial bone growths (0.47 and 0.49 mm/day, respectively) and femur bone growths (0.52 and 0.53 mm/day, respectively) compared with the N‐control group (0.37 mm/day of tibial growth and 0.42 mm/day of femur growth) (p < 0.05). The YH‐1 and YH‐2 groups had significantly different growth plate (proximal epiphysis) height increments (0.62 and 0.56 mm, respectively) compared with the N‐control group (0.17 mm) (p < 0.05). Lastly, the YH‐1 and YH‐2 groups presented different growth hormone (GH) levels (1.77 and 2.10 ng/mL, respectively) than the N‐control group (0.82 ng/mL) (p < 0.05). YH administration increased longitudinal bone growth and GH secretion in rats. Consequently, YH may offer an improved ability to treat GH deficiency‐related disorders. Copyright

Anti-complementary activity of enzyme-treated traditional Korean rice wine (Makgeolli) hydrolysates

BACKGROUND Makgeolli brewed from rice contains about 150 g kg(-1) alcohol and has a fragrance as well as an acidic and sweet taste. During the brewing process, by-products such as rice bran and brewery cake are produced. At the end of fermentation the matured mash is transferred to a filter cloth and the Makgeolli is squeezed out from the cake, leaving the lees of the mash. These by-products have continued to increase every year, resulting in an ecological problem. It is therefore important to develop new uses for them. The objective of this study was to use the by-products from the brewing of Makgeolli as a valuable functional food or nutraceutical. RESULTS The anti-complementary activities of crude polysaccharides isolated from Cytolase hydrolysates of Makgeolli lees at concentrations of 1000 and 500 µg mL(-1) were 84.15 and 78.70% respectively. The activity of polysaccharide krestin (PSK) was 60.00% at 1000 µg mL(-1). The active polysaccharide obtained with Cytolase comprised mainly glucose and mannose (molar ratio 1.00:0.62). CONCLUSION Glucose- and mannose-rich crude polysaccharides were isolated from the Cytolase hydrolysate of Makgeolli lees. The polysaccharides retain anti-complementary activity to enhance the immune system as a functional food or nutraceutical.

Acute and subacute toxicity of yeast hydrolysate from Saccharomyces cerevisiae

The objective of this study was to obtain data on the safety-in-use of yeast hydrolysate in 10-30 kDa molecular weight as a dietary supplement by assessing its acute and subacute oral toxicity in female and male Sprague-Dawley (SD) rats. The single oral dose of the hydrolysate at 5000 mg/kg did not produce mortality or significant changes in the general behavior and gross appearance of the internal organs of rats. In subacute toxicity study, the hydrolysate was administered orally at a dose of 1000 mg/kg/day for a period of 14 days. The satellite group was treated with the hydrolysate at the same dose and the same period and kept for another 14 days after treatment. There were no significant differences in organ weights between control and treated group of both sexes. Hematological analysis and blood chemistry revealed no toxicity effects of Saccharomyces cerevisiae hydrolysate. Pathologically, neither gross abnormalities nor histopathological changes were observed. These results show that the hydrolysate possesses very low toxicity as indicated in SD rat model.

Debittering of corn gluten hydrolysate with active carbon

Corn gluten hydrolysates were treated with active carbons to remove the bitterness. After treatment with active carbons, the ACE (angiotensin-converting enzyme) inhibitory activity decreased in the order of active clay, Junsei (fine and granule) and Koent CPG (67.2, 65.4 and 64.9% respectively) in TP 10K. In addition, that of PP 10K treated with Junsei (fine and granule) and active clay decreased to 75.6, 72.2 and 74.7% respectively. In PP 10K, Koent PWA and active clay effectively reduced the bitterness. PP 10K treated with Koent PWA and active clay was reported to taste as trace of bitterness to slightly bitter. TP 10K treated with Koent RC and CPG tasted as trace of bitterness to slightly bitter, and that treated with Koent PWA and Junsei (granule) tasted as slightly bitter to bitter. After treatment with active carbons, the amounts of T-N (total nitrogen) in PP 10K and TP 10K reduced from 148 and 135 mg to 136–42 and 134–108 mg respectively. Before treatment with active carbons, PP 10K and TP 10K consisted of peptides with APLs (average peptide lengths) 14.4 and 12.8 respectively. After Junsei (fine) treatment, the APLs of PP 10K and TP 10K were 16.9 and 16.2 respectively. After treatment with the other active carbons, the APLs of PP 10K and TP 10K were 14.4–2.78 and 14.4–3.5 respectively. Before treatment with active carbons, the surface hydrophobicities of PP 10K and TP 10K were 38 and 29.9 respectively. However, after treatment with active carbons, the surface hydrophobicities of PP 10K and TP 10K were reduced, except for PP 10K treated with active clay. In PP 10K, treatments with Koent PWA and active clay markedly reduced the surface hydrophobicity from 38 to 13.3 and 14.2 respectively. The surface hydrophobicity of TP 10K treated with Koent RC and CPG was markedly reduced from 29.9 to 9.9 and 11.1 respectively. © 2000 Society of Chemical Industry

Effects of yeast hydrolysate on hepatic lipid metabolism in high-fat-diet-induced obese mice: yeast hydrolysate suppresses body fat accumulation by attenuating fatty acid synthesis.

Aims: We observed whether the anti-obesity activity of yeast hydrolysate (YH) was due to the alteration of lipid-regulating enzyme activities. Methods: Male ICR mice were divided into four groups: a normal diet group (ND; 4.2% fat), a high-fat diet group (HF; 27.7% fat), an HF group treated orally with 0.5% or 1% YH in the drinking water (HF+YH0.5; 27.7% fat and HF+YH1; 27.7% fat). Results: After 5 weeks, the YH groups (HF+YH0.5 = 3.92 ± 0.17 g/100 g BW and HF+YH1 = 3.76 ± 0.13 g/100 g BW) had significantly lower levels of epididymal fats compared to the HF group (4.91 ± 0.29 g/100 g BW; p < 0.05). YH supplementation produced a decrease in serum triglycerides and low-density lipoprotein cholesterol concentrations and body weight gain, and produced a dose-dependent significant increase in serum ghrelin compared with the HF group (p < 0.05). Hepatic glucose-6-phosphate dehydrogenase (G6PD) activity was inhibited by YH supplementation compared with the HF group, and mice treated orally with 1% YH exhibited a significant decrease in hepatic malic enzyme (ME) activity compared to obese mice treated with the vehicle (HF = 10.44 ± 2.74 nmol/min/mg protein vs. HF+YH1 = 6.68 ± 2.23 nmol/min/mg protein; p < 0.05). Conclusions: YH supplementation suppressed body fat accumulation by attenuating fatty acid synthesis through the downregulation of hepatic G6PD and ME activities.

Yeast Hydrolysate Protects Cartilage via Stimulation of Type II Collagen Synthesis and Suppression of MMP-13 Production

Type II collagen (COL II) is one of the primary components of hyaline cartilage and plays a key role in maintaining chondrocyte function. COL II is the principal target of destruction, and matrix metalloproteases (MMPs) have a major role in arthritis. In the present study, we investigated the chondroctye protection effects of specific fraction of yeast hydrolysate ((10–30 kDa molecular weight peptides). The mRNA expression of COL II was significantly increased in the YH‐treated group compared to the control at concentrations above 50 µg/ml, respectively. The 200 µg/ml YH‐treated group (3.43 ± 0.23 µg/ml) showed significantly reduced glycosaminoglycan (GAG) degradation relative to that in the interleukin‐1β (IL‐1β)‐treated control group (4.72 ± 0.05 µg/ml). In the YH‐treated group, MMP‐13 level was significantly decreased in a dose‐dependent manner compared to the IL‐1β‐treated group without YH treatment. However, MMP‐1 and MMP‐3 level were not different from that of control. Under the same conditions, we also examined mRNA levels of COL II. The mRNA expression of COL II was significantly higher in the YH‐treated group than in the IL‐1β‐treated control group at concentrations above 100 µg/ml. In conclusion, YH stimulated COL II synthesis and significantly inhibited MMP‐13 and GAG degradation caused by IL‐1β treatment. Copyright