Physicochemical properties and biological activity of extract from Dioscorea polystachya Turcz. bulbil by combined treatments of enzyme and ethanol

Abstract

The present study was performed to investigate the physicochemical properties and biological activity of extract from Dioscorea polystachya Turcz. bulbil (DPB), registered as novel food ingredients, via a combination treatment using enzyme and ethanol. The results indicated an increase in the degree of starch hydrolysis with an increase in the enzyme treatment time. Furthermore, the treatment time exerted a significant effect on the marked increase in browning index (BI), content of total soluble solids (TSS), and useful component content (p<0.001). The contents of total polyphenols (TP), total flavonoids, and crude saponin (CS) also increased with an increase in the enzyme treatment time (p<0.001). It was determined that enzyme treatment for more than 4 h was unnecessary. The increase in α-glucosidase inhibitory activity was affected by the presence of TP and CS during enzyme treatment. It was concluded that enzyme treatment was effective for a minimum of 30 min and a maximum of 4 h. The present work demonstrated the optimization of the useful and functional components of DPB via a complex treatment using enzyme and ethanol. These profiles provide valuable data in the selection and application of DPB for the development of functional food materials.