Department of Food Engineering. Universidade Federal de São João del Rei, Sete Lagoas, Brazil; School of Chemical Engineering. Universidade Federal de Uberlândia, Uberlândia, Brazil.
Department of Chemical Engineering, Escola Politécnica, Universidade de São Paulo, São Paulo, Brazil.
Food Chem. 2021 Mar 30;341(Pt 2):128287. doi: 10.1016/j.foodchem.2020.128287. Epub 2020 Oct 2.
Microwave heating has been considered a promising technology for continuous flow thermal processing of fluid foods due to better retention of quality. Considering the importance of açai-berry pulp and its perishability, the inactivation kinetics of peroxidase (POD) and polyphenol oxidase (PPO) were investigated under conventional and microwave heating. First-order two-component model was well fitted to the data, indicating the presence of at least two fractions with different resistances. POD was more thermally resistant (90% inactivation for 40 s at 89 °C) and could be considered as a processing target. Inactivation curves dependency on heating technology suggests specific effects of microwaves on the protein structure. Additionally, the dielectric properties of açai-berry pulp were evaluated at 915 and 2,450 MHz for temperatures up to 120 °C. Power penetration depth dropped with temperature at 915 MHz (from 29 to 11 mm), but was less affected at 2,450 MHz (between 8 and 11 mm).
微波加热由于能更好地保持质量，因此被认为是一种有前途的连续流动热加工流体食品的技术。考虑到草莓浆的重要性及其易腐性，研究了过氧化物酶（POD）和多酚氧化酶（PPO）在常规加热和微波加热下的失活动力学。一级双组分模型很好地拟合了数据，表明至少存在两种具有不同抗性的分数。POD 的耐热性更强（在 89°C 下 40 秒即可达到 90%的失活率），可以作为加工目标。失活动力学曲线对加热技术的依赖性表明，微波对蛋白质结构有特定的影响。此外，还评估了草莓浆在 915 和 2450 MHz 下的介电特性，温度高达 120°C。在 915 MHz 时，功率穿透深度随温度下降（从 29 毫米降至 11 毫米），但在 2450 MHz 时受影响较小（在 8 至 11 毫米之间）。
