Effects of ultraviolet C, controlled atmosphere, and ultrasound pretreatment on free ferulic acid in canned sweet corn kernels.

Abstract

Because canned sweet corn kernel (CSCK) products are subject to high market competitiveness, producing them with a higher content of free ferulic acid (FFA), a functional ingredient, using non-thermal and green technologies may be an alternative solution for Thai exporters. This study aimed to investigate the effects of pre-canning ultraviolet C (UVC), controlled atmosphere (CA), and ultrasound treatments on the FFA content, texture, and colour of CSCKs. UVC irradiation (0, 1.94 and 4.01kJ/m2) was tested in combination with storing corn under CA at %O2:%CO2:%N2 ratios of 21:0.03:78, 3:10:87, and 3:15:82 before canning. Based on the FFA content, two UVC-CA pretreatments were selected for the ensuing experiment. The effects of the selected UVC-CAs in combination with 0, 10, or 20min of 35kHz ultrasound before canning were measured. The FFA content, moisture, texture, and colour of the CSCKs treated with the nine UVC-CA combinations were not significantly different. Corn irradiated with 1.94kJ/m2 UVC and stored under 3:15:82 %O2:%CO2:%N2 before canning exhibited the highest FFA content, followed by corn treated with no UVC and stored at 3:15:82 %O2:%CO2:%N2. Corn treated with ultrasound combined with the two selected UVC-CA treatments showed no differences in FFA content, moisture, texture, or colour. Corn kernels treated with UVC-CA-ultrasound had a higher FFA content than untreated kernels. UVC-CA-ultrasound pretreatment showed a trend of increasing CSCK FFA content with no change in physical properties. Thus, UVC-CA-ultrasound pretreatment appears to be an alternative process that might add value to CSCKs by increasing FFA content.