Enzymatic hydrolysis of steryl ferulates and steryl glycosides
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چکیده
Steryl ferulates (SF) and steryl glycosides (SG) are phytosterol conjugates found characteristically in cereals. Currently, little is known about their properties with respect to enzymatic hydrolysis. SF and SG were extracted and puriWed from rye and wheat bran. Their percentages of hydrolysis with diVerent enzymes were studied using normal phase HPLC with UV detection for steryl ferulates and evaporative light scattering detection for steryl glycosides. Steryl ferulates were hydrolysed by mammalian digestive steryl esterases. It was further demonstrated that a mixture of steryl ferulates from rye and wheat was hydrolysed much more eVectively than a steryl ferulate mixture from rice (commonly known as -oryzanol), suggesting greater bioavailability in non-rice steryl ferulates. Steryl glycosides were hydrolysed by a commercial microbial -glucosidase preparation (cellobiase), but were not eVectively hydrolysed by two other highly puriWed -glucosidases. These results demonstrate for the Wrst time the potential use of enzymes as a replacement for acid hydrolysis in analytical procedures for SG and also provide insights about the potential bioavailability of these sterol derivatives in human digestive systems.
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تاریخ انتشار 2007