• Korean Journal of Plant Resources
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• v.23 no.2
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• pp.123-130
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• 2010

Present studies were conducted to investigate the effects of autoclaving on antioxidant activities of Achillea alpina and Solodago virgurea. At early April, young leaves of 2 species were collected, subjected to autoclaving ($121^{\circ}C$, 1.2 atmospheric pressure, 15 minutes), freezed-dried, grinded, and extracted with 80% ethanol. The same process was repeated with unautoclaved control. Total polyphenol and flavonoid contents, scavenging activities on DPPH and ABTS radicals and ferrous ion chelating effects were analyzed. Extraction yield of autoclaved S. virgurea was 39.55% and A. alpina 28.15%. In both species, autoclaving significantly reduced scavenging activities on DPPH and ABTS radicals. On the contrary, ferrous ion chelating effects increased after autoclaving, especially in young leaves of A. alpina. Autoclaving resulted in decrease of polyphenol and flavonoid contents, especially in the A. alpina. The present experiments demonstrated that autoclaving had negative effects on antioxidant activities of A. alpina and S. virgurea, except in ferrous ion chelating effects. Young leaves of former species were unstable to heat treatment, resulting in big lose of antioxidant activity.

• Food Science and Preservation
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• v.22 no.3
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• pp.428-436
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• 2015

Five extraction conditions (AE, autoclave extraction; OE, oven extraction; HWSE, hot water and sonication extraction; HWASE, hot water acidified with 0.5% (v/v) acetic acid and sonication extraction; and BE, boiling extraction) were examined to compare the effects of different hot water extraction methods on the antioxidant properties of blueberries. The extraction yields of the AE, OE, HWSE, HWASE, and BE were 7.94%, 8.35%, 8.55% 9.15%, and 8.50%, respectively. The polyphenol and flavonoid contents of AE were 3.47 mg GAE/g and 1.59 mg RE/g, respectively, which were highest centents among others. Those of OE were ranked second to the highest. The total anthocyanin content of HWSE (5.29 mg/g) was significantly higher than that of others whereas that of AE showed the lowest content (0.96 mg/g). The order of ABTS radical and alkyl radical scavenging activities was as follows: AE > BE > OE > HWSE > HWASE. The antioxidant properties were considerably correspondent with the total polyphenol and flavonoid content. DPPH radical scavenging activity was quite high in HWSE, AE, and BE extraction, however, there were no significant differences among the five extraction methods in the aspect of $Fe^{2+}$ ion chelating activities. Moreover, AE showed the highest SOD activity, and protected the dermal fibroblast the best against $H_2O_2$-induced cytotoxicity. In conclusion, it was suggested that the autoclave extraction (AE) would be the most effective method for preparing blueberry hot water extracts with relatively high antioxidant activities.