Shin-Kyo Chung

An antioxidant hispidin from the mycelial cultures of Phellinus linteus.

In the course of screening for reactive oxygen species scavengers from natural products, an antioxidant was isolated from the mycelial culture broth ofPhellinus linteus and identified as hispidin. The hispidin content was reached its maximum level at 12 days after onset of inoculation. About 2.5 mg/mL of hispidin was produced byP. linteus in a yeast-malt medium (pH 5.8, 25°C). Hispidin inhibited 22.6 and 56.8% of the super oxide anion radical, 79.4 and 95.3% of the hydroxyl radical, and 28.1 and 85.5% of the DPPH radical at 0.1 and 1.0 mM, respectively. The positive control oc-tocopherol scavenged 25.6 and 60.3%, 74.6 and 96.3%, and 32.7 and 77.5% of each radical, respectively, at the same concentrations. However, hispidin showed no significant activity on the hydrogen peroxide radical.

Antiobesity effects of wild ginseng (Panax ginseng C.A. Meyer) mediated by PPAR-γ, GLUT4 and LPL in ob/ob mice

The antiobesity effect of wild ginseng (WG; Panax ginseng C.A. Meyer) in male obese leptin‐deficient (B6.V‐Lepob, ‘ob/ob’) mice was evaluated. WG was administered orally to mice at doses of 100 mg/kg and 200 mg/kg daily for 4 weeks. The WG‐treated ob/ob mice showed a loss of body weight and a decrease in blood glucose levels compared with control mice. WG regulated the mRNA expression level especially, it increased peroxisome proliferators‐activated receptors‐γ (PPAR‐γ) and lipoprotein lipase (LPL) in adipose tissue, as well as glucose transporter 4 (GLUT4) and insulin receptor (IR) in the skeletal muscle and liver. Taken together, these results suggest that WG may play a vital role in the antiobesity effect in ob/ob mice; this has importance in insulin sensitivity. This may prove to be of clinical importance in improving the management of obesity and related metabolic syndromes. Copyright

Enhancing polyphenol extraction from unripe apples by carbohydrate-hydrolyzing enzymes

The effects of process variables such as enzyme types, enzyme ratio, reaction temperature, pH, time, and ethanol concentration on the extraction of unripe apple polyphenol were investigated. The results indicated that Viscozyme L had the strongest effect on polyphenols extraction and was selected to study the polyphenol composition. The ratio of enzyme (Viscozyme L) to substrate (2 fungal beta-glucanase units (FBG)) at 0.02, reaction at pH 3.7, 50 °C for 12 h, and ethanol concentration of 70% were chosen as the most favorable extraction condition. Total phenolic content (TPC), reducing sugar content (RSC), and extraction yield increased by about 3, 1.5, and 2 times, respectively, compared with control. The contents of p-coumaric acid, ferulic acid, and caffeic acid increased to 8, 4, and 32 times, respectively. The enzyme-aided polyphenol extraction process from unripe apples might be applied to food industry for enhancing bioactive compound production.

Antioxidant capacities and polyphenolics of Chinese cabbage (Brassica rapa L. ssp. Pekinensis) leaves

Chinese cabbage (Brassica rapa L. ssp. Pekinensis) is a green leafy vegetable used mainly in kimchi, salted and fermented dishes. Consumer preference for the leaf portion differs according to the type of dishes. In this study, Chinese cabbage was divided into three parts, and their antioxidant activities were investigated through in vitro assays. The total phenolic contents (TPC), total flavonoid contents (TFC), and vitamin C contents were also determined as indicators of antioxidant contents. The phenolic acids and flavonoids were separated and identified using high performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry (LC/MS). The outer leaf had the strongest antioxidant activity with the maximum antioxidant contents, followed by the mid- and inner leaves. Principal component analysis (PCA) revealed that outer leaf is positively related to caffeic acid, p-coumaric acid, ferulic acid, and myricetin contents, whereas the mid- and inner leaves are negatively related to sinapic acid contents.

A prolyl endopeptidase-inhibiting antioxidant from Phyllanthus ussurensis.

A prolyl endopeptidase inhibitor was isolated from the ethyl acetate soluble fraction ofPhyllanthus ussurensis. The active compound was identified as an ellagitannin, corilagin. It was shown to non-competitively inhibit prolyl endopeptidase (PEP) with the IC50 value of 1.17x10-6 μM. TheKi value was 6.70x10-7 M. Corilagin was less inhibitory to other serine proteases such as chymotrypsin, trypsin, and elastase, indicating that it was relatively a specific inhibitor of PEP. Corilagin also effectively inhibited reactive oxygen species such as hydroxide and superoxide anion radical, hydrogen peroxide, and DPPH. Especially, corilagin showed potent scavenging activity on the superoxide anion radical in the ESR method (IC50 = 3.79x10-6 M) as well as xanthine oxidase system.

Comparison of Antioxidant Activities of Radish Bud (Raphanus sativus L.) According to Extraction Solvents and Sprouting Period

The purpose of this study is to investigate the total polyphenol and antioxidant activities of radish buds (Raphanus sativus L.) based on sprouting periods and extraction solvents in order to present basic data that are needed for using the radish buds as functional food material. The antioxidant activities were assessed by using various antioxidant models (DPPH, TBARS, Rancimat method, POV). The total polyphenol contents according to the extraction solvents were 84.11 and 296.51 mg/g, and the ethanol extract on day 4 of showed the highest value as 296.51 mg/g. As for DPPH radical-scavenging activity, on the day 4 of sprouting, water extracts indicated the highest scavenging activity by 86.67%, and the acetone extracts indicated a rather low scavenging activity as 77.23%. As for TBARS measurement of the radish bud extracts on day 4 of sprouting the extract of 70% ethanol was highest (71.48%). On day 8 of sprouting the TBARS value was increased and the methanol extract was highest (78.99%). As for the oxidative induction period on day 4 of sprouting in Rancimat measurement, the methanol extract was highest (6.07 hours) on day 4 and the antioxidant index was 1.16. On day 12 of sprouting, the general oxidative induction period tended to be reduced to 5.25 to 5.91 hours. In the peroxide value measurement on day 4 of sprouting and beginning of the storage, the extracts showed no difference between 3.02 meq/kg oil and 4.12 meq/kg oil, and on the day 60 of storage, the water extract (43.83 meq/kg oil) and the methanol extract (45.42 meq/kg oil) were lowest with higher antioxidant effect. In conclusion, the radish bud extract with higher total polyphenol contents and antioxidant activities may serve as functional material for food additives, such as natural antioxidants and food preserving agents.

Optimization of enzymatic hydrolysis of persimmon peels for vinegar fermentation

Response surface methodology (RSM) was used to determine the treatment conditions of optimal enzymatic hydrolysis for vinegar preparation from persimmon peel. Persimmon peel was hydrolyzed with different concentrations of Viscozyme L (0–4%) at different temperatures (40–60°C) for different lengths of time (2–10 h) followed by vinegar fermentation. Reducing sugar and soluble solids of the hydrolyzed juice were significantly affected by the hydrolysis conditions. Optimal condition was obtained with the enzyme concentration of 2.38 g/100 mL, reaction temperature of 49.19°C, and reaction time of 6.32 h. The titratable acidity of vinegar prepared from the juice hydrolyzed under the optimized condition increased by 276% (4.25 g/100 g). Acetic acid, citric acid, oxalic acid, and succinic acid were identified in the vinegar. Results suggest that the enzymatic hydrolysis pretreatment could be used for increasing the yield of the vinegar fermentation.

Effect of wild Korean ginseng (Panax ginseng) extract on blood glucose and serum lipid contents in rats with multiple low-dose streptozotocin-induced diabetes

Anti-diabetic effects of wild Korean ginseng extracts on multiple low-dose streptozotocin (STZ)-induced diabetic rats were investigated. Rats were administered extracts at rates of 100, 200, and 300 mg/kg of body weight for 8 weeks. Body weight was significantly (p<0.05) lower in ginseng untreated diabetic rats than in ginseng treated rats in spite of significantly (p<0.05) higher food and water intake than for ginseng treated rats. Blood glucose levels were significantly (p<0.05) higher but plasma insulin levels were significantly (p<0.05) lower in 200 and 300 mg/kg of body weight ginseng treated diabetic rats than in rats treated with 100 mg of ginseng and in untreated control rats. The plasma aspartate aminotransaminase level was not significantly (p>0.05) affected; however alanine aminotransaminase and alkaline phosphatase levels were reduced significantly (p<0.05) in higher ginseng dosage rat groups. Anti-diabetic effects were elicited by administration of wild Korean ginseng extracts in multiple low-dose STZ-induced diabetic rats.

Phenolics enrichment process from unripe apples

Unripe apples contain significant amount of phenolics with various health benefits. A pilot scale enrichment process of unripe apple phenolics with Viscozyme L extraction and XAD-7 sorption process, based on the total phenolic content (TPC), phenolics content by high-performance liquid chromatography analyses, and antioxidant activities were studied. Antioxidant activities were tested by measuring oxygen radical absorbing capacity (ORAC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, and ferric-reducing antioxidant power (FRAP). The phenolics-rich final product, apple antioxidant phenolics (AAP) has 771-fold higher TPC and 600-fold higher antioxidant activity of unripe apples. Through XAD-7 sorption AAP showed 52, 87, 70 and 44-fold increases in TPC, ORAC, DPPH and FRAP values, respectively. AAP showed more than 95% stability at the temperature range of 20 to 120°… and pH range of 1.47 to 8.5. Apple phenolics extraction process of Viscozyme L extraction coupled with XAD-7 sorption could be applied to the production of health benefit antioxidants.

Effects of egg shell calcium treatments on the short-term storage of cut Kimchi cabbage

This study was conducted to investigate the effects of egg shell calcium treatments on short-term storage of cut Kimchi cabbage. Egg shell ash powder (ESP-2) had the greatest calcium contents. Calcium solubility was greater in citric acid than acetic acid and ascorbic acid. Cut Kimchi cabbages (3×3 cm) were treated with 0.5%, 1.0%, and 2.0% egg shell powder (ESP-1), and egg shell ash powder (ESP-2), and 0.5% citric acid, put inside polyethylene (PE) bags, and stored at 5°C for 6 weeks. Weight loss was about 99.85-99.90%, and the ratio was the lowest upon 0.5% ESP-2 treatment (p<0.05). The reduction ratios of soluble solids were 21.3-43.4%, and decreased in the order of 1.0% ESP-2 treatment and 0.5% ESP-1. The L* values decreased, whereas a* and b* values of Hunter colorimetry increased in all treatments. ΔE values were lowest upon 0.5% ESP-2 treatment. 0.5% ESP-2 treatment showed better quality characteristics than other treatments. Thus, egg shell calcium treatments could effectively enhance the shelf-life of cut Kimchi cabbage.