Division of Agricultural Engineering, ICAR-IISR, Lucknow, India.
Division of Plant Physiology and Biochemistry, ICAR-Indian Institute of Sugarcane Research (IISR), Lucknow, India.
J Sci Food Agric. 2024 Sep;104(12):7130-7142. doi: 10.1002/jsfa.13536. Epub 2024 Apr 26.
Sugarcane juice, which has a short shelf life, is a popular thirst-quenching and rejuvenating beverage worldwide. The limited shelf life is a result of changes in polyphenol oxidase (PPO) activity, total plate count (TPC) and color attributes (L*, a* and b*-values). We hypothesized that chemical kinetics and thermodynamics of blanched sugarcane cane juice causing alterations in PPO, TPC, and L, a* and b*-values will address the challenges of sugarcane juice preservation.
Sugarcane billets were blanched at variable time-temperature combinations in the range 0-20 min and 70-90 °C. Reaction rates increased with increasing temperature; PPO activity, TPC and colour followed first-order kinetics. PPO activity had an activation energy (Ea) of 81 kJ mol. The half life (t) dropped from 16.5 to 3.47 min and decimal reduction time (D-values) dropped from 54.83 to 11.52 min. Thus reactions were temperature-sensitive. Thermodynamic studies indicated an endothermic (positive enthalpy values, ΔH > 0; 78.10 kJ mol) and reversible process (negative entropy values ΔS < 0; -0.044 kJmol K). Michaeli-Menten constant (K) and maximum velocity (V) of PPO activity were determined by adding variable lemon juice concentrations in sugarcane juice. As the Km values increased (from 5.53 to 15.81 mm) and V values decreased (from 666.67 to 384.61 UmL), a Lineweaver-Burk plot suggested decreased PPO affinity of sugarcane juice.
The results of the present study indicate that studies on chemical kinetics and thermodynamics (PPO, TPC and L, a* and b*-values) of blanched sugarcane cane juice shall mitigate challenges of sugarcane juice preservation. © 2024 Society of Chemical Industry.
甘蔗汁的保质期很短，是一种在世界范围内受欢迎的解渴和恢复活力的饮料。有限的保质期是由于多酚氧化酶（PPO）活性、总平板计数（TPC）和颜色属性（L*、a和 b-值）的变化造成的。我们假设烫漂甘蔗汁的化学动力学和热力学会导致 PPO、TPC 和 L、a和 b-值的变化，从而解决甘蔗汁保存的挑战。
甘蔗坯料在 0-20 分钟和 70-90°C 的范围内以不同的时间-温度组合进行烫漂。反应速率随温度升高而增加；PPO 活性、TPC 和颜色遵循一级动力学。PPO 活性的活化能（Ea）为 81 kJ mol。半衰期（t）从 16.5 分钟降至 3.47 分钟，十进制减少时间（D 值）从 54.83 分钟降至 11.52 分钟。因此，反应对温度敏感。热力学研究表明这是一个吸热（正焓值，ΔH > 0；78.10 kJ mol）和可逆过程（负熵值ΔS < 0；-0.044 kJmol K）。通过在甘蔗汁中添加不同浓度的柠檬汁来确定 PPO 活性的米氏常数（K）和最大速度（V）。随着 Km 值的增加（从 5.53 到 15.81 mm）和 V 值的降低（从 666.67 到 384.61 UmL），Lineweaver-Burk 图表明甘蔗汁中 PPO 的亲和力降低。
本研究结果表明，对烫漂甘蔗汁的化学动力学和热力学（PPO、TPC 和 L、a和 b-值）的研究将减轻甘蔗汁保存的挑战。© 2024 化学工业协会。
