科研之友
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摘要
Oleuropein is an antioxidant olive constituent, but it is liable to degrade into hydroxytyrosol. Oleuropein extract was hydrolyzed by hemicellulase and the results presented that 14 phenols were identified in the ethyl acetate extract of enzymatic hydrolysate by HPLC-MS. Antioxidant activities (DPPH, ABTS, total reducing power, FRAP, and Fe2+ chelating ability) of phenols were all added with the samples concentration increased, and dose-effect relationship also existed. 14 phenols all possessed certain inhibition effect against selected bacteria, and they had better inhibition effect against tested Gram-positive bacterium (Staphylococcus aureus) than Gram-negative bacterium (Escherichia coli). Finally, hydroxytyrosol, oleuropein, eugenol, caffeic acid, and 3,4-dihydroxybenzoic acid could present excellent antioxidant and antibacterial effect, and the two activities mainly had close relationship. @@@ Practical applications @@@ From the previous study we could know enzymatic biotransformation from oleuropein to HT was a promising method. Therefore, HT preparation from enzyme has attracted great attention of researcher. If that, a lot of enzymatic hydrolysate would be produced in the process. So, present study was to use fully the ethyl acetate extract of enzymatic hydrolysate, and to determine the chemical composition of phenolic compounds in EAE by HPLC-MS, and to evaluate their antioxidant and antimicrobial capacity. The result was shown that phenols of oleuropein extract after enzymatic process, therefore, may be suitable as a source of powerful antioxidants and bacteriostatic due to their stronger antioxidant and antibacterial activities. They could be widely applied in functional food industry for preservation.
