College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China.
College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China.
Food Chem. 2018 May 15;248:173-182. doi: 10.1016/j.foodchem.2017.12.065. Epub 2017 Dec 18.
This paper is focused on the effects of radio frequency (RF) heating on the relative activity of polyphenol oxidase (PPO), weight loss, texture, color, and microstructure of potatoes. The results showed that pure mushroom PPO was almost completely inactivated at 80 °C by RF heating. The relative activity of potato PPO reduced to less than 10% with increasing temperature (25-85 °C). Enzyme extract showed the lowest PPO relative activity at 85 °C after RF treatment, followed by the potato cuboids and mashed potato, about 0.19 ± 0.017%, 3.24 ± 0.19%, and 3.54 ± 0.04%, respectively. Circular dichroism analysis indicated that RF heating changed the secondary structure of PPO, as α-helix content decreased. Both electrode gap and temperature had significant effect (P < .05) on weight loss, color, and texture of the potato cuboids. Microstructure analysis showed the changes of potato cell and starch during RF heating.
本论文研究了射频（RF）加热对多酚氧化酶（PPO）相对活性、失重率、质地、色泽和微观结构的影响。结果表明，纯蘑菇 PPO 在 80°C 时几乎完全被 RF 加热失活。随着温度（25-85°C）的升高，马铃薯 PPO 的相对活性降低至低于 10%。酶提取物在 RF 处理后 85°C 时显示出最低的 PPO 相对活性，其次是马铃薯方块和马铃薯泥，分别为 0.19±0.017%、3.24±0.19%和 3.54±0.04%。圆二色性分析表明，RF 加热改变了 PPO 的二级结构，α-螺旋含量减少。电极间隙和温度对马铃薯方块的失重率、色泽和质地均有显著影响（P<.05）。微观结构分析表明，在 RF 加热过程中，马铃薯细胞和淀粉发生了变化。
