Study On Black Tomatoes Preservation And Lowsugar Preserves Processing Technology

Black Tomatoes are rich in anthocyanins,vitamin C,vitamin E and other antioxidants,especially anthocyanins only substance in black tomato among ordinary tomato.Black tomatoes have the function of anti-radiation,anti-cardiovascular disease,improving vision,lowering blood sugar and so on,which have the title of “Functional Fruit”.So the in-depth study of black tomatoes and development of its processing product will have broad prospects.Firstly,this paper studied preservation effect of edible composite film.1.5% of chitosan and 2.5% of chitosan ratio with 0.5% of sodium alginate and 1% of sodium alginate respectively.During the storage at room temperature(22?),treatment groups were compared with the control group(without film),and changes in physical and chemical properties of fruit were measured.The composite films showed the better properties on the composition of 1.5% chitosan and 0.5% of sodium alginate.Then this paper studied the making of low-sugar preserved black tomatoes with fresh black tomatoes.This studied on the technological process and parameters such as heating,hardening,composite filler selection,vacuum permeability,composite sweetener selection and so on.The results showed that:(1)The crack size,sensory and hardness of preserved fruit had the best property at the condition of heating temperature at 75?,3% of ?-glucono-delta-lactone.(2)on the basis of single factor experiment,the optimum composite fillers were obtained by response surface methodology: 0.22% of carrageenan,0.18% of sodium carboxymethyl cellulose and 0.17% of sodium alginate.Under this condition,water losing of black tomato fruit is 53.2396%.(3)The optimum sugar permeability process was obtained by orthogonal experimentaland economic cost consideration: 0.1 MPa of vacuum,vacuum time of 40 min,vacuum temperature at 50 ?.Through sensory evaluation and fuzzy comprehensive evaluation,20% of sugar was the final concentration,the optimum ratio of composite sweeteners—sorbitol: xylitol: sucrose = 1: 1: 1.(4)Referring to the Peleg model,trying to use it to study the temperature and vacuum impact of sugar permeability: Peleg equation fitting curves had a good fitting,the correlation coefficients of K values in temperature test were above 0.96,the correlation coefficients of K values in vacuum test were above 0.95,and predicted values and experimental values were used to calculate the relative error,the values of E(%)were both less than 10%.