乙醇冷藏处理对鲜切马铃薯酶促褐变的抑制及其机理研究

Mechanism of ethanol refrigeration treatment on inhibition of fresh-cut potatoes enzymatic browning

以鲜切马铃薯为原料,研究了乙醇处理对其多酚氧化酶(PPO)活性、过氧化物酶(POD)活性、褐变指数(BI)和丙二醛(MDA)含量的影响,以及酶促褐变底物L-酪氨酸和L-多巴的紫外和红外光谱图的变化来研究乙醇处理对鲜切马铃薯酶促褐变抑制机理。结果表明,分别用4%、5%、6%体积分数的乙醇溶液处理后的鲜切马铃薯在贮藏过程中,PPO活性、POD活性、BI值和MDA含量均低于对照组,且5%体积分数的乙醇溶液处理对酶促褐变的抑制效果最优;通过酶促褐变底物的紫外及红外光谱图可知,乙醇溶液处理对马铃薯酶促褐变的底物的结构没有产生影响,由此可知,乙醇溶液是通过抑制PPO、POD等相关酶的活性来抑制鲜切马铃薯的酶促褐变。

Fresh cut potatoes were used as raw material to investigate the effects of ethanol treatment on polyphenol oxidase(PPO)activity,peroxidase(POD)activity,browning index(BI)value and malondialdehyde(MDA)content. The mechanism of ethanol treatment on enzymatic browning of fresh-cut potatoes were investigated by measuring the changes in the ultraviolet and infrared spectra of the enzymatic browning substrates L-tyrosine and L-dopa. Results showed that PPO activity,POD activity,BI value and MDA content of fresh-cut potatoes treated with 4%,5%,6% ethanol solution were lower than that of the control group;and 5% ethanol treatment had the best inhibitory effect on enzymatic browning during the whole storage period. The ethanol treatment had no effect on the substrate structure of potato enzymatic browning according to ultraviolet and infrared spectrum. It indicated that the inhibition of enzymatic browning was due to the inhibition of enzyme activity,such as PPO and POD.