Identification of principal constituents in enzymatically hydrolyzed coix extract

The structural elucidation of the main constituents in enzymatically hydrol yzed coix extract, a natural food preservative, was carried out. After pera cetylation, five compounds, namely peracetylated forms of glucose, maltose, maltotriose, maltotetraose, and maltopentaose were isolated. The structure s were determined by PFG HMQC and HMBC experiments. In addition, by using H PLC with an RI detector, the main components of this coix extract were iden tified as a mixture of oligosaccharides having one to seven glucose units c oupled through alpha-(1-->4) linkages. Since this extract showed no antimic robial activity, its preservative effect may be caused by its covering of t he food surface, thereby blocking contact with air.