Preparation Of Collagen Film And Gelatin Film From Rana Skin And Their Freshkeeping Effect On Chilled Pork

Frozen pork is rich in nutrients,high water activity and good in sensory quality,but its shelf life is short and it is easy to spoil.Therefore,how to ensure the quality of chilled meat and develop green and safe fresh-keeping materials has become the focus of discussion by scholars at home and abroad.Edible film is a layer of edible film that adheres to the surface of food.It often uses protein,fat,polysaccharide and starch as film-forming carriers,including edible coating films and edible packaging films.The edible film is attached to the surface of the food,which can effectively reduce the loss of moisture and solutes of chilled meat,control microbial contamination,and thus achieve the purpose of extending the shelf life of meat products.In this experiment,collagen and gelatin extracted from the skin of Rana sylvatica were compounded with chitosan with strong anti-pathogenic ability and anti-oxidative ability,respectively,to make a coating liquid for the preservation of chilled pork,and to determine the sensory and pH value of pork,juice loss rate,TBARs value,total number of colonies,etc,and pick out the edible packaging film with better preservation effect,and measure the performance of the edible packaging film and the changes in pork preservation indicators.The results showed that:1.Taking TBARs as the evaluation index,single factor experiments and response surface optimization experiments were carried out on different concentrations of collagen,gelatin and chitosan: Collagen: 0.44g/100 mL,Chitosan: 2.06g/100 mL.Chitosan: 0.9g/100 mL,Chitosan: 2.08g/100 mL.2.The chilled pork was treated with collagen-chitosan coating solution and gelatinchitosan coating solution respectively and stored at 4 ?.The pH value,juice loss rate,TBARs value and total number of colonies of chilled pork were measured and sensory evaluation and other indicators,compared the fresh-keeping effect of the two coating liquids on chilled pork,the results showed that the two coating liquids can effectively reduce the total number of colonies,TBARs value,pH value,juice loss rate of chilled pork.And collagen-chitosan coating solution has better preservation effect on chilled pork than gelatin-chitosan coating solution.3.The gelatin-chitosan packaging film of rana wood skin was prepared,the basic properties of the packaging film were measured,and the preservation effect of the packaging film on chilled pork was studied by wrapping pork with collagen-chitosan packaging film.The results showed that the shelf life of chilled pork wrapped by collagen-chitosan film could be extended for 8d,and the TBARs value,pH value,total colony count and juice loss rate decreased significantly,which were all within the standard range of fresh meat.