| Summary: | 碩士 === 國立嘉義大學 === 食品科學系碩士班 === 92 === Abstract
This study was to investigate the antioxidative and whiting effects of permeate and retentate of mulberry white root extract separated using membrane processing. Permeate and retentate were obtained after processing the extracts of mulberry white root using either a microfiltration membrane (0.45μm) or one of four cut-off size ultrafiltration membranes (UK200, UK50, UP20, UK10) to reach various weight concentration ratio (WCR: 1.5, 2, 3, 4). The effects of membrane process on the physiochemical characteristics, antioxidant ability, whiting ability, and the contents of active compounds in permeate and retentate were evaluated.
Experimental results showed that permeate flux and resistance of fouling layers formed(αpCB) membrane was: 0.45μm＞UK200＞UK50＞UP20＞UK10. pH in permeate and retentate showed slightly changes (4.12~4.23). However, the color indexes of L value (93~96) increased expect treated with UK10 in permeate, which indicated that mulberry white root extract was clarified and became light. The total solids and viscosities of retentate increased as an increasing concentrated fold (WCR). Antioxidative capability showed that permeates were better scavengers of 1,1-diphenyl-2-picryl hydrazyl (DPPH‧) radical. The values of IC50 (50% inhibitory concentration) on scavenging of permeate were 6.92~7.46 mg/mL, especially processing with 0.45μm membrane (IC50=6.92 mg/mL), which was lower than that of feed (IC50=8.72 mg/mL). Total antioxidant ability and reduction power effect of permeate treated with 0.45μm membrane were also the best treatment (IC50= 3.89 mg/mL; 1.43 mg/mL). The IC50= 0.45μm and 1.50 mg/mL of permeate treated with 0.45μm membrane required to inhibit tyrosinase activity and to reduce copper ions, respectively, which indicated that it may be the best treatment for whiting. Furthermore analysis of the main active compounds demonstrated that most active compounds existed in permeate. The contents of active compounds were followed the pattern: chlorogenic acid＞ρ-hydroxybenzoic acid＞ferulic acid. The higher contents of active compounds in permeate may explain the capability of antioxidantive and whiting.
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