Substrate Specificities of Glycosidases from Aspergillus Species Pectinase Preparations on Elderberry Anthocyanins

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• 作者：Sina Pricelius ; Michael Murkovic ; Philip Souter ; Georg M. Guebitz
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2009
• 出版时间：February 11, 2009
• 年：2009
• 卷：57
• 期：3
• 页码：1006-1012
• 全文大小：225K
• 年卷期：v.57,no.3(February 11, 2009)
• ISSN：1520-5118

文摘

Attractive color is one of the most important sensory characteristics of fruit and berry products, and elderberry juice is widely used as natural colorant. When pectinase preparations were used in the production of elderberry juice for clarification, a concomitant decrease of anthocyanins and thus a color loss were observed. This paper demonstrates that this is due to side glycosidase activities contained in commercial pectinase preparations from med-content content-type="genus-species" type="simple">Aspergillusmed-content> sp. Using LC-MS, sequential deglycosylation of cyanidin-3-sambubioside, cy-3-glucoside, cy-3-sambubioside-5-glucoside, and cy-3,5-diglucoside was found to be catalyzed by specific glycosidases contained in the pectinase preparations. There was no big difference in the deglycosylation rate between monoglucosidic or diglucosidic anthocyanins. However, the degradation rate was decreased when rutinose was attached to cyanidin, whereas the structure of the aglycone itself had almost no influence. Pure β-glucosidases from med-content content-type="genus-species" type="simple">Agrobacteriummed-content> species and med-content content-type="genus-species" type="simple">Aspergillus nigermed-content> and the β-glucosidase N188 from A. niger did not show any conversion of anthocyanins, indicating the presence of specific glycosidases. Thus, an activity gel based assay was developed to detect anthocyanin-specific glycosidase activity in enzyme preparations, and according to LC-MS peptide mass mapping of digested bands, homologies to a β-glucosidase from med-content content-type="genus-species" type="simple">Aspergillus kawachiimed-content> were found.