Study On White-blush Of Fresh-cut Carrot And Control It With Coating

Basing on the carrot"F1",three parts were studied:physiological indexes and correlation of white blush of fresh-cut carrot during strorage,peroxidase and phenylalanine ammonia-lyase activity and influence factors of carrot,effects of alginate complex coating on white blush of fresh-cut carrot,the main results were as follow:1,Regulation of WI,lignin content,weight loss,soluble solid content,respiration rate,total carotene content,POD activity,PAL activity of fresh-cut carrot during storage were:WI,lignin content,weight loss,POD activity increased as storage time increased,soluble solid content,respiration rate and PAL activity increased and then decreased,total carotene content decreased during the storage.The correlation between WI and lignin content,weight loss,POD activity was positive and very significant,there was a significant negative correlation between WI and total carotene content,respiration rate had no correlation with WI.2,Enzymatic properties of POD and PAL of carrot showed that the optimum pH were 5.0and8.4,the rules of their activities under the different pH were similar to the rules of their tolerance,the optimum temperature of POD was 30℃, activity of PAL come to the peak during 40℃～50℃.When volume of PAL was 1.6mL,reaction rate come to the highest, and peaks appeared when volume of POD was 1.0mL.When substrate concentration of POD and PAL were 44.8×10^-6mol/L and 0.02mol/L,reaction rate come to maximum.10mmol/L,1mmol/L,0.1mmol/L Na⁺,l0mmol/L Ca²⁺,0.1mmol/L NH₄⁺,10mmol/L,1mmol/L,0.1mmol/L Mg²⁺ could obviously inhibit activity of POD and PAL simultaneously.3,Based on the single factor experiments,effects of alginate complex coating on white blush of fresh-cut carrot were studied,used fresh-cut carrot as material.The mathematic model were built by Central Composite Design in Design Expert software.The result showed that the regression equation fit well,the optimal complex coating compositions for controlling the white blush were:concentration of alginate 10.28g/L,gelatin concentration 4.98g/L,sodium stearate concentration 2.55g/L.Under this condition,white index of fresh-cut carrot was 30.64.The mathematic model could exactly forecast white index of fresh-cut carrot.