Effects of Dual-Frequency Ultrasound with α-amylase on the Properties and Structure of Mung Bean Starch

Abstract

In this paper, we focus on the effects of dual-frequency ultrasound (40 and 80 kHz) with a-amylases (5U/g) on the properties and structure of mung bean starch. The reducing sugar value and starch solubility in the treated starch slurry under ultrasound enzyme were studied. Scanning electron microscopy (SEM) and Fourier transform infrared spectrometer (FTIR) were used to measure the apparent structure and crystal texture of starch. The results indicated that compared with the results of single-frequency ultrasound treatment, dual-frequency ultrasound promoted the starch hydrolysis by amylase and increased the starch solubility remarkably. More channels and holes were found on the surface of treated starch granule by SEM. The results of FTIR analysis showed the FTIR peak shape of ultrasonic treated starch was different from that of the control starch.