Study On The Storage Qualities And Preservation Technology Of Fresh-Cut Carrots

Fresh-cut fruits and vegetables are harder to maintain its quality than full fruits and vegetables due to the destruction of the organizational structure, so its shelf life is greatly shortened. Therefore,study on the storage qualities and preservation technology of fresh-cut fruits and vegetables is important.With fresh-cut carrots as material, aimed at the quality problems of fresh-cut carrots during storage, this study researched the shelf life prediction and preservation technology of fresh-cut carrots. Main contents include: physiological and biochemical changes and their correlation of fresh-cut carrots during storage,establishment and evaluation of shelf life prediction model about fresh-cut carrots, main enzymes activity and influence factors of carrots, effect of chemical preservatives on quality of fresh-cut carrots,and effect of high oxygen modified atmosphere packaging on quality of fresh-cut carrots. Main results and conclusions are as follows:(1) With the extension of storage time, regulation of L value, a value, whiteness value, weightlessness rate and PPO, POD, PAL activity of fresh-cut carrots were: L value, a value decreased during the storage, whiteness value, weightlessness rate increased, PPO, POD, PAL activity increased and then decreased. By grey correlation analysis found that PAL is the leading cause of those lead to fresh-cut carrots changing white.(2) Studied the texture index of fresh-cut carrots during storage by TPA test, the results show that: The first cycle firmness, second loop firmness, chewiness decreased during the storage, cohesiveness and flexibility had changed little. Through correlation analysis, found that the first cycle firmness between the loop firmness, elasticity, hardness, cohesiveness, chewiness were strong linear correlation. Therefore, the first cycle firmness can be used as a representation of the important parameters for its quality.(3) Established the shelf life prediction model which was about firmness of fresh-cut carrots. The relative error of the actual value and the predicted value of the shelf life prediction model established in this experiment obtained in less than 10%. So it can be used to predicte the remaining shelf life of fresh-cut carrots based on the firmness within the temperature range 277-293 K.(4) Different concentrations of citric acid and ascorbic acid on PPO, POD, PAL activities of fresh-cut carrots all have different degrees of inhibition, and the inhibition degree increase with the increase of concentration of inhibitors.The optimal temperature of POD has two, guess the isoenzyme POD existed in fresh-cut carrots.(5) The optimal fresh-keeping agent for controlling the white blush were:0.8% citric acid + 0.4% Vc + 0.2% calcium chloride, in which the dominant factor was citric acid. best combination of 0.8%, Keep the texture index of fresh-cut carrots was calcium chloride.(6) Modified atmosphere containing 40% O2 is not suitable for fresh-cut carrots. Modified atmosphere containing 100% O2 had the best fresh-keeping effect on fresh-cut carrots. Packaging with 60% O2 and 80% O2 also had the fresh-keeping effect on fresh-cut carrots, but it could not match the effect of packaging with 100% O2.