Preparation Of Curdlan/bacterial Cellulose/Cinnamon Essential Oil Composite Film And Its Application In Chicken Preservation

Biodegradable film is a kind of biodegadable film with protective function,barrier function and preservation function,which is made from natural renewable materials.To some extent,it can relieve environmental pressure by replacing the currently used synthetic polymer film.Curdlan(CD)is a kind of polysaccharide produced by fermentation in microbial bacteria.It is soluble in alkali and insoluble in water at room temperature.However,it will gradually form a flexible gel under heating conditions.It has good thermal stability.Nowadays,CD is widely used in food industry.Bacterial cellulose(BC)is a general name of cellulose synthesized by microorgnisms such as acetic acid bacteria under different conditions.It has fine network structure,high mechanical strength,good water absorption and water retention.This paper studied the formation of composite membrane by adding BC into the CD solution.Based on the original properties of the CD membrane,bacterial cellulose was used to improve the film formation and mechanical properties of the CD membrane.In addition,cinnamon essential oil(CEO)with antibacterial and antioxidant effects was added to the membrane to endue the membrane with antibacterial and antioxidant properties,and to improve the barrier properties of the membrane.To increase the shelf life of the chilled meat,the composite membrane was applied to wrap the chilled meat and store it at 4?.The results of this experiment are asfollows:1.The effects of adding bacterial cellulose on the membrane properties of curdlan were studiedTake the mechanical strength index as a reference,the optimal addition amount of BC was determined to be 2%of dry matter.The CD/BC composite film was prepared by Water soluble method and alkali soluble method,and the final process was determined as follows:A.water soluble method:Add mass fraction 4.0%CD in distilled water,mxing with 2%BC(ratio of dry matter,w/w),20%glycerol(ratio of dry matter,w/w)and 20%of Tween 80(ratio of dry matter,w/w).Hydrochloric acid was used to adjust the pH to 4.0.After homogenization,50 ml of the membrane solution was poured into the PTFE mold plate(18 cm×18 cm),heated at 100? for 2 min,and then dried for 24 h under the conditions of humidity 50%and temperature 25?.B.alkali soluble method:Add mass fraction 2.0%CD in 0.25 mol/L NaOH,mixing with 2%BC(ratio of dry matter,w/w),20%glycerol(ratio of dry matter,w/w)and 20%of Tween 80(ratio of dry matter,w/w).Hydrochloric acid was used to adjust the pH to 4.0.After homogenization,100ml of the membrane solution was poured into the PTFE mold plate(18cm×18cm),and then dried for 24h under the conditions of humidity 50%and temperature 25?.After the preparation of composite film,the physical and chemical indexes were analyzed.The results showed that when the addition amount of BC was 2%(ratio of dry matter,w/w),the tensile strength of the water-soluble and alkali-soluble films will increased by 22%and 42%,the thermal stability and crystallinity of the film were improved.In addition,the addition of BC inproved the water resistance performance of CD film,reduced the moisture content of CD film,and a certain amount of BC improved the brightness of the film.Conpared with water-soluble CD membrane,alkali-soluble CD membrane has higher tensile strength,better thermal stability and lower moisture content,but water-soluble CD membrane has better elongation-at-break and water resistance.2.The effects of adding cinnamon essential oil on the properties of CD/BC composite film were studiedThe addition amount of BC was 2%(ratio of dry matter,w/w),and 0%,5%,10%,and 15%(ratio of dry matter,w/w)of CEO were added to the membrane solution to study the influence of cinnamon essential oil on the performance of CD/BC composite film.The results showed that when the CEO concentration was 10%(ratio of dry matter,w/w),the tensile strength of water-soluble and alkali-soluble films increased by 5%and 19%,the elongation-at-break increased by 36%and 27%.The water resistance and optical performance of the composite film were also improved,but the crystallinity and thermal stability of the CD/BC composite film decreased after the CEO was added.The alkali soluble CD/BC/CEO composite film has higher tensile strength and better thermal stability than the water soluble CD/BC/CEO composite film,but the water soluble CD/BC/CEO composite film has better fracture elongation,optical properties and water resistance properties.3.The preservation effect of composite film on chilled meat was studiedThe composite films were prepared by adding 2%BC(ratio of dry matter,w/w)and 10%CEO(ratio of dry matter,w/w)to the pure CD membrane.Refrigerated chicken mince are wrapped in composite film and stored at 4?.The results showed that the preservation performance of the composite film was effectively improved after the CEO was added,and the growth of microorganisms in chicken mince was inhibited,and the time when the TVB-N exceeded the limit was extended from 6d to 9d,delaying the spoilage of chicken mince.