| Summary: | 碩士 === 國立屏東科技大學 === 食品科學系 === 88 === Abstract
The objectives of this research were to investigate the antioxidative properties of methanolic extracts from grape (cv. Black Queen) seeds and skin in Taiwan. The study items including antioxidative characteristics, antioxidative activity in different lipid peroxidation systems, contents of some antioxidant, the estimation of their toxicity, and mutagenicity by Ames test.
The methanolic extracts of grape seeds (MEGSE) and skin (MEGSK) exhibited higher extract yield and showed greater antioxidative activity than n-hexane and ethyl-acetate extracts. The antioxidation activity of MEGSE and MEGSK at 400 ppm was lower than butylate hydroxyanisole(BHA), however, stronger than α-tocopherol. The MEGSE and MEGSK were slected to be experimental materials.
The antioxidative characteristics of MEGSE and MEGSK were investigated. MEGSE and MEGSK exhibited remarkable antioxidative activity inhibited 90.1% and 75.3% peroxidation of linoleic acid at 400 ppm, respectively. MEGSE and MEGSK showed 88.2% and 75.7% scavenging effect onα,α-diphenyl-β-picryhydrazyl(DPPH) at 100 ppm, respectively. The scavenging effects of MEGSE and MEGSK on superoxide anion were 88.2% and 75.7% at 100ppm, and on hydroxyl radical were 25.3% and 24.2% at 1mg/mL, and on hydrogen peroxide were 40.0% and 38.7% at 1mg/mL, respectively. In addition, the reducing power of MEGSE was higher than 10-fold concentration MEGSK. The chelating ability on Fe+2 of MEGSE was near to the 2-fold concentration MEGSK.
Antioxidative activity of MEGSE and MEGSK were determined using different linoleic acid peroxidation systems that
included by various prooxidants (including autoxidation, Fe+2, Fe+3, Fe+2/H2O2, and Fe+3/H2O2/ascorbic acid). MEGSE and MEGSK exhibited the high antioxidative activity in autoxidation
system than in other induced systems. The inhibition of peroxidation in Fe+3 system of MEGSE and MEGSK were higher than those induced by Fe+2, Fe+2/H2O2, and Fe+3/H2O2/ascorbic acid at 400 ppm. When concentration was 1000 ppm, the inhibition of peroxidation of MEGSE and MEGSK was also in order of Fe+3 > Fe+2/H2O2 > Fe+3/H2O2/ascorbic acid > Fe+2. The inhibition of peroxidation(%) of MEGSE was better than MEGSK in any peroxidation system and in any concertration, but it were increased with the increasing of concentration in various peroxidation systems.
The contents of ascorbic acid, flavonoid, total phenol and β-carotene in MEGSE were 3.4 ppm, 67.4 mg/100g, 702.9 mg/g and 36.8 ppm, and in MEGSK were 172.2 ppm, 353.0mg/100g, 53.1 mg/g and non-detectable, respectively. The contents of -α, -β, -γ, and -δ form tocopherol in MEGSE were 91.8, 4.3, 2.0 ppm, and non-detectable, and in MEGSK were 11.3, 3.3, 15.8, and 3.2 ppm, respectively. The content of total tocopherol in MEGSE was 3-fold MEGSK.
No toxicity and mutagenicity were found in MEGSE and MEGSK toward Salmonella choleraesuis subsp. choleraesuis CCRC 12377 and CCRC12378 (ordered from food industry research and development institute) with or without S-9 mix at tested dosage (0.5-5.0 mg/plate) by Ames test. The results indicated that MEGSE and MEGSK can passed the microorganism gene toxicology and mutagenic test.
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