The objective of this study was to evaluate the effect of fermentation time on the antioxidant activity of tempeh, a fermented product from soybean. Rhizopus oligosporus was used to ferment soybean for 0, 1, 2, 5 and 10 days. Lyophilised tempeh powder was extracted with hexane followed by petroleum ether, ether, 95% ethanol and water. Antioxidant activities of the extracts were evaluated with various models including a,adiphenyl-b-pricryl-hydrazyl (DPPH) and superoxide-scavenging activities, reducing power and inhibitory activity towards lipid peroxidation. The results revealed that tempeh showed greater antioxidant activities than unfermented soybean. On behalf of a DPPH scavenger, water extracts were as good as 95% ethanol extracts. In comparison of superoxide anion-scavenging activity, inhibition of lipid peroxidation and reducing power, 95% ethanol extracts were superior to water extracts. Tempeh fermented with R. oligosporus for 10 days exhibited the highest antioxidant activities than the others.

Abstract:A graph is C 5 -saturated if it has no five-cycle as a subgraph, but does contain a C 5 after the addition of any new edge. We prove that the minimum number of edges in a C 5 -saturated graph on n ≥ 11 vertices is sat(n, C 5 ) = 10(n−1)/7 −1 if n ∈ N 0 = {11, 12, 13, 14, 16, 18, 20} and is 10(n−1)/7 if n ≥ 11 and n ∈ N 0 .

A graph is C5‐saturated if it has no five‐cycle as a subgraph, but does contain a C5 after the addition of any new edge. We prove that the minimum number of edges in a C5 ‐saturated graph on n≥11 vertices is sat(n, C5)=⌈10(n−1)/7⌉−1 if n∈N0={11, 12, 13, 14, 16, 18, 20} and is ⌈10(n−1)/7⌉ if n≥11 and n∉N0. © 2009 Wiley Periodicals, Inc. J Graph Theory

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