Study On The Effect Of Chitosan Straight Chain Cornstarch Cinnamaldehyde Composite Film On Strawberry Preservation

Fragaria ananassa Duch.is a perennial herb of the family Rosaceae.However,the strawberry is delicate and has a high water content.It has no hard skin to protect the flesh,and it is easily rotten and deteriorated.Meanwhile,strawberry is a non respiratory climacteric fruit.Its respiratory enhance with subsequent ripening increase,and its metabolism accelerates.Its shelf-life is usually 1～2 D,and loss of commodity value.This experiment prepared chitosan amylose corn starch cinnamaldehyde oil film according to determination of the tensile strength,elongation,water vapor permeability,haze and transmittance,biodegradability,colour difference and bacteriostasis of strawberry dominant.The films prepared was applied to preservation of strawberry,and determinated soluble solids content,Vc content,titratable acidity,weight loss,hardness,decay index and sensory evaluation of strawberry during the storage.Present study was designed to prepare a preservative film that can protect strawberry through a green,safe,effective,economic and simple way.Present study can also provide some theory evidence for later research.The main achievements obtained through this experiment are as follows:(1)The single factor experiment was used to determine the tensile strength,the elongation at break and the vapor transmission coefficient,and the single factor ratio of chitosan,straight chain corn starch and glycerol was 2.5%,6% and 1%,respectively.(2)Orthogonal experiment was carried out according to the results of single factor experiment.The orthogonal experiment was designed with 3 factors and 3 levels.The criterion was the tensile strength,the elongation at break and the water vapor transmission coefficient,and the main factors were glycerin,chitosan and direct corn starch.The ratio of three were 2.5%,7% and 0.5%,respectively.(3)The compound film of essential oil was prepared by adding cinnamaldehyde oil of 0.4%,0.8%,1.6%,2%,2.5%,3.2% and 6.4% to chitosan straight chain corn starch glycerol solution.The lowest bacteriostasis of strawberry predominant Staphylococcus ash was14.11 mm,the maximum bacteriostasis was 27.90 mm,and Rhizopus to Rhizopus Rhizopus.The bacteria low bacteriostasis was 11.99 mm,the maximum bacteriostasis was 32.08 mm,the lowest bacteriostasis of Escherichia coli was 3.45 mm,and the maximum bacteriostasis was43.81 mm.The added value of special essential oil had obvious bacteriostasis effect in 1.6%and greater value.At the same time,the TS value of the essential oil is 6.4%,the minimum value is only 4.79 MPa,the E value of the essential oil 3.2% is 0.95%,the 2% of the delta E is1.6%,187.60%,the color difference of 2.5% is 254.25% and the color difference is significant(p<0.01).At the same time,the fog value of 1.6% is lower than that of the three,the lower the fog is,the lower the fog value package.The more beautiful,based on the above analysis,choose 1.6% cinnamaldehyde essential oil.(4)Through the infrared test,it is shown that in the process of film forming,the chitosan /starch / cinnamaldehyde solution produces hydrogen bonds between the three,and there is a crosslinking effect between the molecules.The physical and chemical properties of the film can be enhanced and some cinnamaldehyde molecules are embedded.The film has the function of the release of essential oil.(5)The chitosan starch cinnamaldehyde composite film has a remarkable preservation effect on three kinds of brand strawberries,which can reduce the loss of its nutritional value.For the soluble solids of the three kinds of strawberries,the content of Vc,the titratable acid value and the weight loss rate,the essential oil group has a certain inhibitory effect on the reduction of the strawberry,and can effectively keep the strawberry nutrition value.(6)The chitosan starch cinnamaldehyde composite film has significant preservation effect on three kinds of brand strawberries,which can reduce the decay rate.The decaying grade of the essential oil film group in the seventh test is grade III.Compared with the CK group,the effect of inhibiting the strawberry decay rate is significant.In the sensory evaluation,the essential oil film group can be compared to the CK group from the appearance,color and smell.Effectively preserve strawberry flavor,delay strawberry senescence,and ensure strawberry commercial value.