Thermal and Thermosonication Blanching of Sugarcane Billets: Enzyme Kinetics and Quality Assessment

ABSTRACT Sugarcane juice is an ultimate health‐promoting elixir however its high susceptibility to deterioration due to enzymatic, microbial and chemical reactions paves a barrier in its commercialization. The objective of this study was to compare the effectiveness of thermal (TB) and thermosonication blanching (SB) of sugarcane billets on the polyphenol (PPO) enzyme inactivation kinetics and quality of sugarcane juice. The temperature–time combination of 70°C, 80°C, 90°C for 0, 3, 6, 9, 12, 15, and 18 min were employed for both the blanching treatments. The results showed that out of four mathematical models employed to describe the inactivation kinetics of PPO in sugarcane billets, the weibull model was found best in both the blanching treatments ( R 2 ≥ 0.994). The efficiency of SB was found to be evident as the residual activity reduced by less than 10% in 12 min as compare to TB in 15 min at 90°C. The activation energy of PPO inactivation was 37.29 and 44.37 kJ/mole in TB and SB treatments. At blanching temperature of 90°C, the juice yield dropped 7.2% and 16.3% in SB and TB respectively with respect to unblanched sample (Control). Total soluble solids (TSS) decreased significantly in both the blanching treatment. The other physicochemical parameters namely pH, ascorbic acid, total phenolic content and color was best retained in juice obtained from SB treated sugarcane billets. Overall, the findings suggest that thermosonication blanching of sugarcane billets at 90°C for 12 min was found optimum for inactivation of PPO enzyme with improved juice quality.