【摘要】 目的:探讨远红外辐射加热对山药多酚氧化酶活性及构象的影响。方法:采用不同的远红外辐射温度对山药进行预处理，研究不同远红外辐射温度对山药多酚氧化酶(PPO)活性、褐变度、总酚含量及PPO构象的影响。结果:当辐射温度为260℃时，处理11 min后PPO酶活仍未钝化，辐射温度高于260℃时，PPO在3～7 min内即可失活；褐变度与总酚含量不随辐射温度的升高和处理时间的增加而规律性变化。经远红外预处理后，随着辐射温度的升高，无规则卷曲和α-螺旋含量有轻微的变化，β-转角减少、β-折叠增加，表明远红外改变了PPO的二级结构。PPO紫外光谱蓝移，荧光光谱红移，表明PPO三级结构发生改变。结论:远红外辐射加热能改变山药中PPO构象并有效钝化PPO活性。更多还原

【Abstract】 Objective: This study aimed to investigate the effect of far infrared radiation heating on the oxidase activity and conformation of polyphenol oxidase(PPO) of yam. Methods: By using different far infrared radiation temperatures, the effects of different far infrared radiation temperatures on yam PPO activity, browning degree, total phenol content and PPO conformation were studied. Results: When the radiation temperature is 260 ℃ PPO enzyme is not deactivated after 11 min. When the radiation temperature is higher than 260 ℃, PPO can be inactivated within 3～7 min. However, the browning degree and total phenol content did not change regularly with the increase of radiation temperature and treatment time. After far-infrared pretreatment, the contents of random curling and α-helix changed slightly with the increase of radiation temperature, while β-angle decreased and β-folding increased, indicating that far-infrared radiation changed the secondary structure of PPO. The ultraviolet spectrum of PPO shifted blue and fluorescence spectrum shifted red, indicating that the tertiary structure of PPO changed. Conclusion: Far-infrared radiation heating can change the conformation of yam PPO and eventually deactivate it.更多还原