Study On Fresh-keeping Technology Of Fresh-cut Yam

This paper by fresh yam as materials,the processing technology of preservation technology,through the different storage temperature and different heat treatment temperature,citric acid,ascorbic acid,and sodium chloride four stabilizer.color-protecting 1-cysteine preservation technology research,to study the pHysical and chemical indicators in the process of storage(weight loss rate,hardness,the L value,a value,b value,Browning degree and malondialdehyde),nutritional composition(moisture,starch,reducing sugar,protein,polypHenol)and Browning on the changes of enzyme(PPO enzyme activity,the activity of POD and PAL enzymes)change,the preservation conditions are determined,The control mechanism of Browning was also discussed from the key enzyme level.Main research contents and results are as follows:(1)under different storage temperature,review the pHysical and chemical properties change of yam,the results show that 4? low temperature environment can inhibit Browning of yam,reduce the respiration intensity of yam,prevent the loss of its internal material.(2)the different heat treatment conditions,about 45? heat treatment can kill microorganisms on the surface of the yam,and to a certain extent,reduce the activity of PPO and PAL enzyme activity,prevent the Browning.(3)the results showed that citric acid,ascorbic acid,1-cysteine and sodium chloride could inhibit Browning and enzyme activity of yam to some extent,such as:At the end of the storage period of 10 days,and without stabilizer.color-protecting processing of PPO,POD and PAL enzymes in the control group,compared with citric acid,ascorbic acid,L-cysteine and sodium chloride to the activity of PPO decreased about 40%?60%,the activity of POD decreased about 90%?110%,the activity of PAL decreased about 59%,in the process of storage,the enzyme activity of the three enzymes were gradually with the extension of storage time on the rise,and due to the increase of enzyme activity,so cause Browning degree increase.But after four stabilizer.color-protecting processing,three kinds of enzyme activity and Browning degree were declined,at the end of the storage period,stabilizer.color-protecting locked into the treatment group compared with control group,through the surface of yam,significantly observed in the control group on the surface of the odds and sensory changes,such as brown spots and processing group still had a white color,no obvious color change,indicating that four stabilizer.color-protecting are able to have a relatively good fresh color effect.(4)through orthogonal experiment,the order of primary and secondary factors of the color-protecting agent influencing the fresh yam preservation effect was determined as follows:Vc was the most influential,followed by NaCl and citric acid,and finally 1-cysteine.The best color protection formula is:citric acid concentration of 1.5%or 2%,Vc concentration of 0.8%,1-cysteine concentration of 0.1%,NaCl concentration of 1.5%.Compared with the control group,the Browning rate of yam decreased by 52%under the optimized process conditions.However,in the single-factor experiment with only four kinds of color protective agents,the inhibition rate of Browning of yam decreased by only about 40%,and the effect was not as good as that of orthogonal compound color protective agent.