The Preparation Of Curdlan And Chitosan Composite Membranes And Its Application On Chilled Meat

Edible packaging film is defined as membrane,which is formed by interacting between different molecules and come from nature and edible material such as protein,polysaccharide,cellulose land derivatives,et al.In recent years,edible packaging film become a hotspot with its safey,biodegradability and other characteristics.As a new type of green packaging materials,edible packaging film has certain defects in some performance,so that its scope of application is limited.It could improve the application ability of edible packaging film if blend in variety of membrane material to optimize the physical and barrier properties of the composite membranes.Chilled meat is the most reasonable processing mode after livestock and poultry were slaughtered.It has some advantages,such as safety and hygiene,good sensory quality and high nutritional value.However,there are still some microbial growth and reproduction in low temperature,the shelf life is less than one week under normal circumstances.At present,the main packaging methods of chilled meat are vacuum packaging,atmosphere packaging,coating packaging and so on,but these conventional methods are difficult to achieve in storage and transportation,and even affect the smell and color of chilled meat.To solve the above problems,this study prepared edible films which could be applied in the chilled meat preservation with curdlan and chitosan.The following research results were obtained:1.Process conditions of the curdlan/chitosan composite membrane were determined.To study the effects of the concentration of curdlan and chitosan,the ratio of blend and heat treatment on the properties of the composite membranes.The optimum preparation process was as follows:1.5%of the available curdlan and chitosan mother liquor 4:1 ratio was mixed at 60?,the pH of the mixed membrane solution was adjusted to 4.5,adding a certain amount of glycerol to final concentration of 40%,stirring and ultrasonic degassing,pouring into the teflon plate(18cm × 18cm),stripping the membranes after dry 24h in 25?,RH50%.2.Add tea polyphenols to improve the antioxidant capacity of composite dmembranes.To study the effects of adding tea polyphenols on the properties of the curdlan-/chitosan composite membranes and the antioxidant capacity of the composite membranes.The performance of curdlan/chitosan composite membranes also was studied,including mechanical properties,water vapor transmission coefficient,water content and thermal stability.The results showed that the addition of tea polyphenols reduced the mechanical properties and improved the water vapor transmission coefficient of the composite membranes.The SEM and FT-IR analysis of curdlan/chitosan composite membranes showed that there was good compatibility between the components.The composite membranes with tea polyphenols had antioxidant capacity,and the scavenging ability of DPPH free radical was up to 87.72%when adding 50mg tea polyphenols compound membranes.3.To achieve the applications of curdlan/chitosan composite membranes on chilled meat.The curdlan/chitosan composite membranes containing tea polyphenols were used to wrap chilled meat.The results showed that the composite membranes containing tea polyphenols could effectively improve the indicators of chilled meat and extend the shelf life of cold meat for four days.