Studies On The Key Technologies Of No-additive Sugar Kiwi Preserved Fruit During Processing

To produce preserved kiwi without adding sugar by using Chinese gooseberry as raw materials,xylitol as sweetener,which replacing sucrose as candied sugar permeability matrix,the critical produce process of no-additive sugar preserved kiwi were studied,including pre-treatment procedures(peeling and color-protecting),shaping technology,shelf technology and drying technology.The main research results were as follows:(1)Research on the soda peeled process of preserved kiwi fruitThe suitable hardness of kiwi for producing preserves was about 10 kg/cm2 and the significant effect factors of kiwi lye peeling were temperature of peeling treatment,concentration of sodium hydroxide and treatment time in sequence.To obtain a good quality fruit of smooth bare surface,hard flesh and remaining green color without any impurities or odors,the optimum process parameters of kiwi peeling were soaked the kiwi with 15%concentration of sodium hydroxide at 92 ? in 120s.Under these treatment conditions,peel and pulp of kiwi were separated sufficiently and maintained the shape preferably.(2)Research on the color-protecting technology of preserved kiwi fruitJudging the effect of color-protecting technology by the PPO enzyme activity inhibition,the affect factors of kiwi PPO enzyme activity were followed by blanching temperature,citric acid additive content and blanching time.The optimum parameters of blanching process were adding 0.2%concentration of citric acid at 90 ? in 80s,and then it showed a 98.3%of enzyme inactivation rate achieved with lightness color of preserved kiwi.(3)Research on the shaping technology of no-additive sugar preserved kiwi fruitThe suitable additive amount of xylitol was 30%,and the ratio of composite polysaccharide excipient of CMC:pectin was 1:1,and the optimum additive content was 0.14%.The body of preserved kiwi was fully under these conditions,and the cell structure was similar with those traditional high-sugar preserved fruit after drying.(4)Research on the shelf technology of no-additive sugar preserved kiwi fruitThe study on the shelf technology indicated the appropriate water content was 20%and the secure water activity of storage was under 0.68.The suitable Aw-lowing reagents were composed by glycerine,sodium chloride and sodium lactate.Through the rotary quadratic combination design by factors of the above three kinds of Aw-lowing reagents and the index of reduce Aw(?Aw),with statistically analyzed at a significant level(? = 0.05),the simplified regression equation was established as belows:Y=0.0417+0.00841X1+0.01161X2+0.00751X3In the model,FR=6.266>F0.01(9,13)=4.19,which means the regression was significant,and FLf=0.523<F0.05(5,8)=6.63,which means the fitting was not significant.Therefore,it showed the model had a certain correlation to reflect the relationship of actuality.The factors of influencing the ?Aw were followed by the sodium chloride content,the sodium lactate content,and the glycerine content.Each factor was reached a most significant level.(5)Research on the drying technology of no-additive sugar preserved kiwi fruitThe optimum parameters of combining the drying process in no-additive sugar preserved kiwi was by the initial drying in 14min at Mass ratio of microwave power 2w/g,then transferring to hot air drying at 60 ? in 180min.In conclusion,the total drying time last 194min.The equation of initial microwave drying was described by MR=exp(-ktn),and the equation of later hot air drying was described by Henderson and Pabis model MR = Aexp(-kt).The whole drying progresses mathematical model equations of no-additive sugar preserved kiwi fruit were as follows:(?)...