Effect Of Edible Film On Quality In Fresh-Cut Fruit

Fresh cut fruit which have a characteristics of natural, nutrition, fresh, convenient and satisfy the demand for food, nutrition, has a huge development potential. This paper focus on quality preservation problem,takes peach and pear as test materials,studies on its preservative effect of edible coating on fresh cut fruit.It selects the appropriate coating materials, and screenes through the orthogonal experiment of the optimum ratio of composite color protecting coating preservation liquid and on the basis of this study, the changes of color, hardness, weight loss rate, PPO activity and total phenolic content of fresh cut fruits were studied. the research also study the water vapor and microstructure of composite coatingfor the technical support of fresh cut fruits, the main research contents and results are as follows:Through the study of 9 kinds of liquid membrane（chitosan, chitosan oligosaccharide, CMC, sodium alginate, carrageenan, soy protein, whey protein, konjac glycoside polysaccharide, pullulan polysaccharide） disposewith fresh cut peach and pears, found konjac glucomannan film coating liquid treatment of fresh cut peach effect better, and carrageenan coating processing of fresh cut pears effect is better.On the basis of the previous chapter,by single factor and orthogonal konjac glucan-mannan glycan, carrageenan, potassium sorbate, V_C, citric acid and anhydrous calcium chloride compound preservative film composition proportion was studied,and the results showed that 2.0% of KGM + 1.5% V_C + 0.1% citric acid + 1.0% calcium chloride can significantly maintain fresh-cut peach hardness, color and other physical and chemical properties, sensory variety in flavor and texture remain optimal level. The best fresh-cut pear composite preservative formulation is 1.5% carrageenan + 0.1% V_C + 0.15% potassium sorbate + 1.0% calcium chloride, using the composite of edible film can significantly maintain pear pieces in optimal level.At the same time, the effects of spraying, brushing and soaking on fresh cut peach and pear color, hardness, weight loss rate, soluble solids content, PPO activity and total phenol content were studied, the results show that compared with the control group, three coating process of fresh cut fruit effects are significantly better（P < 0.05）. Compared between the each treatment group which is better than that of control group, the quality of fresh peach is significantly better than spraying treatment and brush treatment（P < 0.05）, while spraying treatment and brush between overall difference is not obvious difference（P > 0.05）, which can be concluded that soaking the coating process of fresh cut peach effect is best; With the method of spraying process on the quality of fresh cut pear significantly better than other coating methods（P < 0.05）, between the soaking treatment with brush is also significant difference（P < 0.05）, the spraying process of fresh-cut pear block effect is best.Finally, the water vapor and microstructure of the composite coating were studied to showed that, the water vapor presenceof Amorphophallus konjac glucomannan composite coating is 0.14×10⁸ g/m²*24h and water vapor permeability coefficient of thatis 0.015g*mm/cm²*S*Pa. And by scanning electron microscopy（SEM） the microstructure of the coatings were observed and found the film cross-section smooth, dense and uniform and non porous; the water vapor permeance of carrageenan film is 0.92×10⁴g/m²*24h and water vapor permeability coefficient of that is 4.7×10^-8g*mm/cm²*S*Pa. The microstructure of the coating was observed by scanning electron microscope, and the cross section of the film was irregular cross-section, fine and loose network structure.