Study Of Effect Of Super High Pressure On Quality Of Fresh-cut Potatoes

Products are processed and sensory indicators are evaluated by using fresh cut potato silk as raw material, ultra high pressure at 100,200,300,400,500,600MPa and holding time for 5,10,15 and 20 min respectively, the optimal treatment conditions are confirmed in combination with the browning degree of 11d stored under 4 degrees, the total number of colonies, texture evaluation results; On such basis, the improvement of calcium, ion on product hardness by combining the treatment of calcium chloride is studied; and enzymes, phenols and micro structure of browning of 12d stored under 4 degrees with regard to fresh-cut potatoes are measured. The results are as follows:(1) According to the sensory evaluation, the treatment conditions of the super high pressure are respectively 300MPa and 500MPa for 10min.(2) With the expansion of holding time, the hardness remarkably decreases regarding 400MPa, other pressures are compared by using both 10 min and 5min with great drop and no significant change is seen after 10 minutes. Pressure is from100 to 600MPa with10min treatment. Compared with the control group, the retention rates of hardness are respectively 97.78%,97.05%,90.22%,75.43%,73.23% and 69.33%.(3) Following 10min treatment, the browning degree under 400MPa increases significantly compared with the control group, and the browning degree of the rest decreases. The total number of colonies is significantly inhibited under above 400MPa, previously the inhibition effect is not obvious. In the storage period, the total number of colonies and browning degree under above 400MPa show a weak momentum of growth. There is significant difference in comparison with control group.500MPa and 10min are the treatment condition of super high pressure by summarizing 1,2 and 3.(4) Products are processed by using calcium chloride with a concentration of 0.4%, 0.6%,0.8%,1.0% and 1.2%,coupled with super high pressure. With an increase of concentrations, products are increasingly hardening. The product smells bitter withl.2% of the calcium chloride, as a result, this experiment processes the product by selecting 1.0% calcium chloride for hardening as the super high pressure. After processing, hardness for the first cycle increases from 73% to 88%, the electrolyte permeability decreasing. Evaluated by microbial indicators, product could be preserved lOd at 4℃.(5) During the storage period, PPO, POD and PAL are three categories of enzyme, whose change regarding enzyme activity and total phenolic content is significantly lower than the control group, showing that super high pressure changes browning degrees by inhibiting the enzyme activity. Super high pressure process lead to the deformation for part of cells, causing certain damage to the tissue cells of product.