Research And Application Of Fresh Cut Water Chestnut Fresh-keeping Packaging And Antibacterial Polyethylene Packaging Film

Water chestnut is a kind of vegetable with high nutritional value.It is not only edible,but also medicinal.Although water chestnut is loved by consumers,its cleaning and peeling are more troublesome and it is not durable for storage.At present,consumers pay more and more attention to food safety and packaging quality.How to meet the needs of industrial peeling while guaranteeing the taste and quality of water chestnut and extend its shelf life.,which is the current fruits and vegetables fresh-keeping researchers have been studying the hot spot.Fresh-cut water chestnut after peeling treatment will cause mechanical damage,the pulp contact with air and microorganisms,not only prone to a variety of biochemical reactions that are not conducive to fresh-keeping and storage,but also easy to grow and reproduce microorganisms contaminated in the air,resulting in deterioration of the quality of fresh-cut water chestnut,shortening its shelf life,thus greatly limiting the market of fresh-cut water chestnut.In this study,fresh-cut water chestnut was pretreated with household condiments such as salt,sugar and white vinegar as fresh-keeping liquid,then modified with potassium sorbate,modified SD resin,calcium propionate and other modifiers on polyethylene as base material and made antimicrobial fresh-keeping film.Then,fresh-keeping liquid and antimicrobial packaging thin were studied.The effects of membrane on fresh-cut water chestnut at room temperature were as follows:1.The effect of fresh-keeping liquid on fresh-cut water chestnutThe fresh-cut water chestnut was soaked and pretreated with salt,sugar and white vinegar,then packaged and stored at room temperature(25?).The hardness,weight loss,total color difference,polyphenol oxidase activity,total phenol content and soluble solids of fresh-cut water chestnut were determined in a specific time.Number and sensory evaluation of odor and bagging were carried out.The following conclusions were drawn: the soaking treatment of fresh-cut water chestnut can effectively delay the deterioration of fresh-cut water chestnut quality during storage.The best combination of fresh-keeping solution was 80g/LSalt + 3g/L sugar + 100g/L vinegar + soaking time for 15 minutes.Compared with the control group,the fresh-cut water chestnut can be extended for 6 days.2.Effect of Different Additives on Modified Low Density Polyethylene FilmsLow density polyethylene(LDPE)was used as the base material.The modified polyethylene particles were prepared by blending potassium sorbate,modified SD resin,calcium propionate and other modifiers with LDPE through twin screw extruder.Then the modified polyethylene particles were mixed with polyethylene resin for extrusion casting to prepare calcium propionate modified polyethylene bacteriostatic film.The optical properties,mechanical properties,water vapor permeability,permeability,microstructure and bacteriostatic properties of the film were tested and analyzed.The results showed that the proportion of additives in the films still affects the properties of the films.When the mass fraction of calcium propionate is 2% and that of modified SD resin is 2%,the films obtained have the best properties.3.Effect of additives of different quality on modified polyethylene filmIn order to improve the barrier and freshness-keeping properties of antimicrobial films,the linear low density polyethylene(LLDPE)was used as the base material.First,the modified polyethylene particles were prepared by blending calcium propionate and other twin-screw extruders.Then,the modified polyethylene particles were mixed with polyethylene resin to produce calcium propionate modified polyethylene antimicrobial film.The optical properties,mechanical properties,water vapor permeability,air permeability,microstructure and bacteriostatic properties of the films were tested and analyzed.The results show that the proportion of additives in the films still affects the properties of the films.When the mass fraction of calcium propionate is 2% and that of modified SD resin is 2%,the films obtained have the best properties.4.Effect of different packaging methods on fresh-cut water chestnutThe The fresh-keeping solution and calcium propionate modified bacteriostatic film were applied to fresh-cut water chestnut packaging under normal temperature.The total color difference,hardness,weight loss,soluble solids content,polyphenol oxidase activity and sensory evaluation of fresh-cut water chestnut were measured.It was found that the fresh-keeping effect of composite fresh-keeping solution combined with calcium propionate modified bacteriostatic film packaging on fresh-cut water chestnut was better than that of single bacteriostatic film treatment and control group during storage.The storage period of fresh-cut water chestnut could be prolonged 10 days by synergistic treatment of the two methods.