Cheng Le, Bai Haoyue, Zhang Mingfang, Yang Fengping, Ren Difeng, Du Yunpeng
Institute of Grassland, Flowers and Ecology, Ornamental & Edible Lily Engineering Research Center of National Forestry and Grassland, Beijing Academy of Agriculture and Forestry Sciences, 100097, Beijing, China.
College of Biological Science and Technology, Beijing Key Laboratory of Forest Food Processing and Safety, State Key Laboratory of Efficient Production of Forest Resources, Hebei Province Key Laboratory of Sustainable Utilization and Development of Forest Food Resources, Beijing Forestry University, Beijing, 100083, China.
Curr Res Food Sci. 2025 Apr 25;10:101062. doi: 10.1016/j.crfs.2025.101062. eCollection 2025.
The emerging technology of inhibiting polyphenol oxidase (PPO) is crucial for preventing enzymatic browning in food. This study aimed to investigate the effects of 4.5 kJ/m ultraviolet (UV)-C radiation and 0.02 mg/mL L-cysteine (L-cys) treatment on the enzyme activity, physico-chemical properties, thermal properties, structure, and molecular microstructure of PPO. UV-C/L-cys decreased PPO activity and had the highest aggregation index and turbidity of PPO. UV-C/L-cys further reduced the denaturation temperature point and increased the denaturation enthalpy of PPO. UV-C/L-cys turned the α-helix to random coil of PPO and destroyed the tertiary structure. This combined treatment aggregated the microstructure of PPO, which led to covering the active center of the enzyme, leading to its inactivation. Molecular docking simulation confirmed that L-cys bound to PPO through hydrogen bonding and ionic contact. This study established a foundation for the application of UV-C radiation and L-cys treatment to control food browning.
抑制多酚氧化酶（PPO）的新兴技术对于防止食品中的酶促褐变至关重要。本研究旨在探讨4.5 kJ/m紫外线-C（UV-C）辐射和0.02 mg/mL L-半胱氨酸（L-cys）处理对PPO的酶活性、理化性质、热性质、结构和分子微观结构的影响。UV-C/L-cys降低了PPO活性，且PPO的聚集指数和浊度最高。UV-C/L-cys进一步降低了PPO的变性温度点并增加了其变性焓。UV-C/L-cys使PPO的α-螺旋转变为无规卷曲并破坏了三级结构。这种联合处理使PPO的微观结构聚集，导致酶的活性中心被覆盖，从而使其失活。分子对接模拟证实L-cys通过氢键和离子接触与PPO结合。本研究为应用UV-C辐射和L-cys处理来控制食品褐变奠定了基础。
