The effect of sonication and heat treatment on the physicochemical, nutritional and microbiological properties of different sugarcane variants

Red sugarcane (RS) is a lesser bred of sugarcane variant in Malaysia compared to yellow sugarcane (YS), thus less data is available regarding this species. In this study, the physicochemical and microbiological properties of RS was determined and compared with YS under different conditions. Both sugarcane variants were subjected to heat and sonication treatments for 5 and 15 minutes as a method for preservation. RS contains a higher degrees Brix (15) compared to YS (14), and was unchanged while YS demonstrated a significant reduction. Furthermore, RS displayed a superior fructose (+802%), glucose (+119%) and sucrose (+17.91%) levels in all samples and they were largely preserved during both treatments. However, RS was sensitive to colour changes, as darker juice (decrease in lightness and increase in redness) was produced after treatments. RS possessed lower phenolic content (-31.15%) and antioxidant activity (-11.51%) than YS, and was significantly affected by both treatments. Sonication was more effective in reducing the microbial content than heat in both treatments. These findings indicated that RS is better at retaining its physicochemical properties under preservation treatment, but less resistant in preserving its appearance and nutritional values.