Attribution Analysis of Lactuca sativa Var. Angustata Enzymatic Browning

To analyze the main contributory factors to enzymatic browning of Lactuca sativa var. angustata,browning degree,total phenol content,polyphenol oxidase(PPO)activity,peroxidase(POD)activity of Lactuca sativa var. angustata head,stem and root in 0,4,8,20,30,48 h and their increasing rates in each time period,the correlation coefficients between browning degree and total phenol content,PPO activity,POD activity in different parts and in different times were respectively investigated with peeled spring moss. The results showed that the browning degree of Lactuca sativa var. angustata improved significantly between 8~30 h(p<0.05),the browning degree of the head was much higher than the stem and root of Lactuca sativa var. Angustata,so the head was the important part to control the browning. Total phenol content increased at first and then decreased with time,and it achieved the peak value at 20 h;The activity of PPO and POD increased gradually with the time progress,while the increasing rate of PPO and POD activity reached highest level respectively in 8~20 h and 20~30 h. The correlation coefficients showed that both PPO activity and POD activity had extra significant correlation with browning degree of Lactuca sativa var. angustata head,stem and root(p<0.01);Total phenol content had significant correlation with browning degree at 0,30 h after peeled(p<0.05);PPO activity and POD activity had extra significant correlation with browning degree at 48(p<0.01);PPO activity and POD activity were the key factors of Lactuca sativa Var. Angustata enzymatic browning.