• Food Science and Biotechnology
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• v.18 no.6
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• pp.1435-1438
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• 2009

Hydrothermal treatment of rice hull was hydrothermal carried out at 105, 110, $121^{\circ}C$ for 15, 30, 60 min, respectively, using a conventional autoclave. Antioxidant activity of the hydrothermal treated rice hull extract was evaluated by determining total phenol contents (TPC), 1,1-diphenyl-2-picylhydrazyl (DPPH) radical scavenging activity (RSA), reducing power, and ABTS RSA. TPC, DPPH RSA, reducing power, and 2,2-azinobis(3-ethylenebenzothiozoline-6-sulfonic acid) (ABTS) RSA of the extract were significantly increased with increasing treated temperature and time. For example, hydrothermal extracts at $121^{\circ}C$ for 60 min increased the TPC, DPPH RSA, reducing power, and ABTS RSA to 0.840 mg/mL, 64.77%, 1.437, and 92.11%, respectively, while those of the extracts treated at $105^{\circ}C$ for 60 min were 0.508 mg/mL, 51.23%, 0.819, and 45.22%, respectively. The results indicated that hydrothermal treatment of rice hull was very effective to increase phenolic compounds and antioxidant activity of rice hull extract.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.6
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• pp.774-779
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• 2006

The commercial green tea leaves were packaged with polyethylene film and irradiated by electron beam at doses of 0, 5, 10, 20, and 30 kGy. After irradiation, green teas were prepared by soaking the leaves in water (1 g/100 mL) at $75^{\circ}C$ for 10 min, and the physicochemical characteristics of green tea were determined. Electron beam irradiation decreased total phenol contents (TPC), total flavanol contents (TFC), ascorbic acid contents (AAC). Irradiation at dose of 20 kGy decreased TPC, TFC, and AAC from 223.46, 32.50, and 6.03 mg/g to 202.88, 31.16, and 5.57 mg/g, respectively, compared with non irradiated control. Electron beam irradiation also decreased catechins, caffeine, and nitrite scavenging activity of green tea. However, the changes of overall color and radical scavenging activity of irradiated green tea were negligible.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.1
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• pp.131-134
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• 2005

The effect of far-infrared (FIR) irradiation on the antioxidant activity of extracts from rice hulls was evaluated. Rice hulls (9 g) were placed in Pyrex petri dishes (8.0 cm diameter) and irradiated at 80, 90, 100, 110, 120, 130 or 14$0^{\circ}C$ for 10,20,30,40,50 or 60 min with a FIR heater, respectively. After FIR irradiation, methanol extract of rice hulls was prepared, and total phenol contents (TPC) and radical scavenging activity (RSA) of the extracts were determined. FIR irradiation of rice hulls at 11$0^{\circ}C$ for 60 min increased TPC of the methanol extract from 51.6 $\mu$M to 104.3 $\mu$M compared to those of non-irradiated control. The irradiation at 12$0^{\circ}C$ for 60 min also increased RSA of the extract from 16.23% to 69.40%. These results indicated that appropriate FIR irradiation onto rice hulls could liberate the covalently bound phenolic compounds that have antioxidant activities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.9
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• pp.1580-1583
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• 2004

The effect of far-infrared (FIR) radiation on the antioxidant activity of extracts from Citrus unshiu peels (CPs) was evaluated. CPs (5 g) were placed in Pyrex petri dishes (8.0 cm diameter) and irradiated at 150$^{\circ}C$ for 10, 20, 30, 40 or 50 min with a FIR heater. After FIR irradiation, 70% ethanol extract of CPs were prepared and total phenol contents (TPC), radical scavenging activity (RSA) and reducing power of the extracts were determined. FIR radiation of CPs at 150$^{\circ}C$ for 30 min increased the TPC and RSA of ethanol extract from 71.9${\mu}$M to 133.9 ${\mu}$M and from 29.64% to 51.27%, respectively, and reducing power was increased from 0.451 to 0.675, compared to those of non-irradiated control. These results indicated that FIR radiation onto CPs could liberate and activate covalently bound phenolic compounds that have antioxidant activities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.10
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• pp.1392-1396
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• 2009

Antioxidative effects of rice hull extracts pre-treatment with various organic acids were evaluated. After incubating rice hull in 50 mM of five different organic acid solutions (acetic, citric, lactic, phosphoric, and tartaric acid) for 18 hours at room temperature, hydrothermal treatment at $121^{\circ}C$ for 30 min was carried out. Antioxidant activity of the rice hull extract was evaluated by determining total phenol contents (TPC), DPPH radical scavenging activity (RSA), reducing power (RP), and ABTS RSA. Pre-treatment with 50 mM phosphoric acid significantly increased TPC, DPPH RSA, and RP, while it decreased ABTS RSA. The effect of phosphoric acid concentration was also determined. TPC and DPPH RSA of rice hull extract increased with concentration of pre-treated phosphoric acid; in contrast, RP showed the reverse pattern. The results indicated that pre-treatment of rice hull with organic acid was very effective for increasing phenolic compounds and antioxidant activity of rice hull extract.

• Journal of Food Hygiene and Safety
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• v.28 no.4
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• pp.337-341
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• 2013

After it was known that an antioxidant function was associated with a reducing risk of cancer and cardiovascular disease, a large number of plant have been investigated for their antioxidant activity. However, lacking of the extensive antioxidant data in vegetables, a few natural antioxidant was used in the food industry. Therefore, this study was carried out to provide some scientific antioxidant activity data in the various vegetables. The samples (n = 275) including 24 kinds of vegetables were examined for antioxidant activity. Total Phenol Contents (TPCs) were measured colorimetric determination method using the Folin-Ciocalteu reagent by gallic acid as the control group. DPPH radical scavenging activity were also investigated using calculation of $IC_{50}$(concentration of extracted needed to inhibit 50% of the DPPH radical). The contents of TPCs were $0.32{\sim}49.26{\mu}g/kg$ and DPPH radical scavenging activity ($CI_{50}$) was 0.0~2.43 mg/mL in vegetables. The best antioxidant effect was shown in Garlic for both antioxidant assay methods.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.10
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• pp.1619-1624
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• 2005

The effect of far-infrared (FIR) irradiation on the antioxidant activity of extracts from grape seed (GS) was evaluated. GS (5 g) were placed in Pyrex petri dishes (8.0 cm diameter) md FIR irradiated at 150$^{\circ}C$ for 10, 20, 30, 40 or 60 min with a FIR heater. After FIR irradiation, water extract (WE) (1.0 g/10 mL), methanol extract (ME) (1.0 g/10 mL) and 70$\%$ ethanol extract (EE) (1.0 g/10 mL) of GS were prepared, and total phenol contents (TPC) and radical scavenging activity (RSA) of the extracts were determined. The antioxidant activities of GS extracts increased as FIR irradiation. For example, FIR irradiation of GS at 150$^{\circ}C$ for 10 min increased the TPC and RSA of WE from 0.95 mM to 1.84 mM and 33,87$\%$ to 58.55$\%$, respectively, compared to non-irradiated control. In the case of ME at the same conditions of FIR irradiation (150$^{\circ}C$ for 10 min), the TPC and RSA also increased from 3.4 mM to 4.52 mM and 76.55$\%$ to 89.41$\%$, respectively. The TPC and RSA of EE increased from 2.65 mM to 4.82 mM and 66.89$\%$ to 84.62$\%$, too. According to the GC/MS analysis, several low-molecular-weight phenolic compounds such as vanillic acid and 3,4-hydroxy benzoic acid were newly formed in the EE after FIR irradiated at 150$^{\circ}C$ for 10 min. There were slight differences in the kinds of phenolic compounds between EE of non irradiated control and FIR irradiated samples. These results indicated that FIR irradiation onto GS could enhance antioxidant activities of its extracts with increasing the amount of phenolic compounds.

• Applied Biological Chemistry
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• v.48 no.4
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• pp.400-403
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• 2005

The effect of far-infrared (FIR) irradiation and heat treatment on the antioxidant activity of extracts from defatted soybean meal (DSM) was evaluated. DSM were placed in pyrex petri dishes (8.0 cm diameter) and irradiated at $150^{\circ}C$ for 5, 10, 15, 20, 40 or 60 min with a FIR heater or simple heater. After FIR irradiation or simple heat treatment at same conditions, methanol extracts of DSM were prepared and total phenol contents (TPC), radical scavenging activity (RSA) and reducing power of the extracts were determined. The antioxidant activities of the extracts increased as the time of heating or FIR-irradiation increased. When DSM were FIR-irradiated at $150^{\circ}C$ for 15 min, the values of TPC, RSA, and reducing power of the extracts increased from 31.62 mg/ml to 57.51 mg/ml, 11.6% to 53.1%, and 0.068 to 0.147, respectively, compared to the untreated controls. Simple heat treatment of DSM under the same conditions ($150^{\circ}C$ for 15 min) also increased the TPC, RSA, and reducing power of the extracts from to 58.04 mg/ml, 65.2% and 0.160, respectively. The results indicated that appropriate FIR-irradiation or heat treatment on DSM increased the antioxidant activities of methanolic extracts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.1114-1117
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• 2005

The effects of far-infrared (FIR) irradiation and heat treatment on the antioxidant activity of extracts from peanut shells was evaluated. Peanut shells were placed in pyrex petri dishes (8.0cm diameter) and irradiated at $150^{\circ}C$ for 5, 10, 15, 20, 40 or 60min with a FIR heater. After FIR irradiation or simple heat treatment at same conditions, methanol extracts of peanut shells were prepared and total phenol contents (TPC), radical scavenging activities (RSA) and reducing powers of the extracts were determined. The antioxidant activities of the extracts increased as the time of heating or FIR-irradiation increased. When peanut shells were FIR­irradiated at $150^{\circ}C$ for 5 min, the values of TPC, RSA, and reducing power of the extracts increased from 40.17mg/mL to 42.30mg/mL, $67.7\%\;to\;76.3\%$, and 0.569 to 0.639, respectively, compared to the untreated controls. Simple heat treatment of peanut shell under the same conditions $(150^{\circ}C\;for\;5min)$ also increased the TPC, RSA, and reducing power of the extracts from 40.17mg/mL to 43.52mg/mL, 67.7\%\;to\;79.3\%$ and from 0.569 to 0.623, respectively. The results indicate that appropriate FIR-irradiation or heat treatment on peanut shells could increase the antioxidant activities of methanolic extracts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.12
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• pp.1628-1632
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• 2007

The present study describes the preliminary evaluation of antioxidant activities and antigenotoxic effect of Rhododendron mucromulatum Turcz. flowers (RMF). The samples were prepared by extracting RMF with four different solvents (methanol, ethanol, acetone, and water), and antioxidant properties were evaluated by determining total phenolic contents (TPC), DPPH radical scavenging activity (RSA), and reducing power (RP). Water extract showed the highest total phenol content (328.1 mg/g gallic acid equivalents). Acetone extract showed the most potent RSA and RP. The $IC_{50}$ for RSA and RP in the acetone extract were 78 mg/mL and 454 mg/mL, respectively. The 200 mM $H_2O_2$ induced DNA damage, measured by Comet assay, was inhibited with water, methanol and acetone extract in dose dependent manner in human leukocytes. The inhibition rates were 42, 62, and 52% at the concentrations of 50 mg/mL of water, methanol and acetone extracts, respectively. These results suggest that R. mucromulatum Turcz. has significant antioxidative activity and protective effect against oxidative DNA damage.