Synthesis Of Multifunctional Bio-protein Coating And Its Application In Fresh-cut Fruits

As the pace of human life is getting faster and faster,the fresh-cut fruit industry has risen rapidly in recent years,but the problem of the short shelf life of fresh-cut fruit has been exposed,which has become another major problem facing humankind.At this stage,the preservation of fresh-cut fruits mainly depends on plastic wrap,but the large amount of plastic wrap will cause serious environmental pollution.In this article,a fresh-keeping method which is green,easy to operate,low in cost and can be applied to most common fruits in the market to extend the shelf life of fresh-cut fruits at room temperature has been proposedFirstly,the reduction reaction between lysozyme and cysteine has been used to form a phase transition solution,which could form a two-dimensional film on the food surface by self-assembly.The two-dimensional film could be coated on almost any substrate with strong adhesion properties,and control the loading and release of various molecules on demand.On this basis,pectin was added to the phase-inversion solution in order to enhance the functionality of the membrane.This two-dimensional film could encapsulate pectin on the surface of fresh-cut fruits,and extend the shelf life of fresh-cut fruits at room temperature.Secondly,in order to verify the function of the film,the fresh-cut fruit was immersed in the preservative to form a two-dimensional film on the surface of the fruit to explore the fresh-keeping ability of the two-dimensional film on the fresh-cut fruit.Through dip coating experiments of various fruit,we have demonstrated that the fresh-keeping liquid could form a film on the surface of fresh-cut fruits to help preserve the fresh-cut fruits,which could extend the shelf life of fresh-cut fruits at room temperature,with an elongation rate of 75%-900%.This article takes fresh-cut apples as an example to study the effects of preservatives on the physical and chemical properties of fruit weight loss,hardness,browning,etc.It was found that compared with the control group,the preservatives could reduce the weight loss rate of the experimental group by 60%;malondialdehyde content decreased by 39.19%;PPO content decreased by 28.57% in the control group,POD content decreased by 29.27% in the control group;hardness was 4 times of the control group;browning index decreased by 31.15% in the control group;and The content of Vc and soluble solids was not changed basically.At the same time,it could inhibit the reproduction of fungi on the fruit surface with no cytotoxicity,and would not affect the normal growth of mice.The preparation method of this preservation liquid was very simple with low cost(500 m L preservation liquid cost only RMB 3 for the fresh-keeping of 40 apples),which could effectively reduce breathing and the browning degree of fresh-cut fruits,and maintain hardness and Vita min C content etc.to extend the shelf life of fresh cut fruits.At the same time,cytotoxicity experiments and animal experiments were performed on the system,which proved that the system was non-toxic and did not affect the growth of mice.Consequently,the preservation system we studied in this article could be a promising method to extend the shelf life of processed fruits.