Preliminary Study On The Technique And Mechanism Of Pre-cutting Treatment To Inhibit Fresh-cut Potato Browning

Fresh-cut potato is one of the main fresh-cut products with great demand in China.However,fresh-cut potato is prone to browning which shortens the shelf life.The common methods of inhibiting browning were either complicated or unsafe.Pre-cutting treatment,as an easy and safe method,was studied to prevent the browning of fresh-cut potato in the paper.Prior to ftesh-cut process,pre-cutting was conducted with cutting off the peel(3-4 cm in length and 1-2 cm in width)at both ends of potatoes and then stored at 5 and 20℃ for a while.The influence of pre-cutting on browning-related enzymes and substrates were studied.To investigate the browning inhibition mechanism of pre-cutting,the gene expression of protease inhibitor,the activity of proteinase and the contents of free amino acids were also studied.The results were as followed:1.Pre-cutting significantly inhibited the browning of fresh-cut potato.The results showed that potatoes stored at 20℃ for 18 h exhibited the least browning degree during the storage of fresh-cut potato.Compared with control,stored at 20℃ for 18 h prolonged the shelf life from 1 d to 5 d.2.The browning inhibition of pre-cutting was achieved by enhancing the antioxidant activity and lowering the metabolism of phenolics and membrane permeability.Compared with control,pre-cutting(18 h)significantly inhibited the activity of PPO and PAL,and the content of total phenolics and MDA,and increased the activity of SOD and POD and the total antioxidant activity.3.The results of qRT-PCR,protease activity and free amino acids showed that pre-cutting upregulated the gene expression of 10137,increased the activity of Kunitz and Bowman-Birk trypsin inhibitor,decreased the total protease activity and free amino acids content.