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A steam explosion pretreatment process followed by methanol extraction has been applied for releasing and extracting phenolic compounds, as well as other effective components, from barley bran. The steam explosion treatment was performed at different temperatures ranging from 210 to 250 °C, with a residence time of 30 s. The effect of residence time was also studied in the range 10 s to 120 s at 220 °C. The extracts were evaluated for their total soluble phenolic content (TSPC) including total free phenolic acids (TFPC) and total soluble conjugates (TSC), identified phenolic acids, total antioxidant capacity (TAC), water-soluble carbohydrates (WSC) and total methanol extracts (TME). High-performance liquid chromatography (HPLC) coupled with a photodiode array detector (PDA) was used in this study for the analysis of p-coumaric acid and ferulic acid in barley bran before and after steam explosion. Our results indicate that TSPC and TAC increased with residence time. They also increased dramatically with temperature up to 220 °C. After steam explosion at 220 °C for 120 s, the TSPC reached 1686.4 gallic acid equivalents mg/100 g dry weight, which was about 9-fold higher than that of the untreated sample. The TSPC and TAC obtained were highly positively correlated (r = 0.918-0.993), which meant that the increase of TAC for the steam explosion pretreated barley bran extracts was due, at least in part, to the increase of TSPC in the methanol soluble fraction. Also, under optimum conditions, the WSC in aqueous solution was 5 times as much as that of the untreated sample, which demonstrated that steam explosion also hydrolyzes carbohydrates into water-soluble sugars. It can be concluded that a proper and reasonable steam explosion pretreatment could be applied to release the bound phenolic compounds and enhance the antioxidant capacity of barley bran extracts.
Many studies indicate that an anthocyanin-rich diet has beneficial effects preventing metabolic disease. In the present study, the molecular mechanism underlying the antiobesity effect of consuming blackberry anthocyanins (BLA) and blueberry anthocyanins (BBA) was investigated in high-fat-diet- (HFD-) fed C57BL/6 mice. Sixty mice were administered a low-fat diet (LFD), a HFD, or a HFD plus orlistat, and BLA or BBA in their daily food for 12 weeks. As a result, the consumption of BLA and BBA inhibited body weight gain by 40.5% and 55.4%, respectively, in HFD-fed mice. The BLA and BBA treatments markedly reduced serum and hepatic lipid levels and significantly increased hepatic superoxide dismutase and glutathione peroxidase activities. In addition, the treatments effectively increased fecal acetate and butyrate levels and significantly attenuated expression of tumor necrosis factor TNF-α, interleukin-6, and nuclear factor-kappaB genes. Moreover, gas chromatography time-of-flight mass spectroscopy results suggested that BLA and BBA significantly affected the hepatic lipid and glucose metabolic pathways, including glycerophospholipid metabolism, glutathione metabolism, and the insulin-signaling pathway. Therefore, BLA and BBA ameliorated diet-induced obesity by alleviating oxidative stress and inflammation and accelerating energy expenditure.
This study investigated the phenolic compounds of 15 Chrysanthemum morifolium Ramat cv. ‘Hangbaiju’, including 6 ‘Duoju’ and 9 ‘Taiju’, using high performance liquid chromatography (HPLC). The antioxidant activities of these ‘Hangbaiju’ were estimated by DPPH, ABTS and FRAP assays. Results show that a total of 14 phenolic compounds were detected in these flowers, including 3 mono-caffeoylquinic acids, 3 di-caffeoylquinic acids, 1 phenolic acid and 7 flavonoids. ‘Duoju’ and ‘Taiju’ possess different concentrations of phenolic compounds, and ‘Taiju’ exhibits higher caffeoylquinic acids and stronger antioxidant activities than ‘Duoju’. Caffeoylquinic acids show a strong correlation with the antioxidant activities of the samples. Principal component analysis (PCA) reveals an obvious separation between ‘Duoju’ and ‘Taiju’, using phenolic compounds as variables. Apigenin-7-O-glucoside, 3,5-di-O-caffeoylquinic acid, luteolin and acacetin were found to be the key phenolic compounds to differentiate ‘Duoju’ from ‘Taiju’.
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