Preparation Of Compound Essential Oil Microcapsule Antibacterial Film And Its Application In Low Sodium Bacon

With the improvement of people’s health awareness and environmental protection awareness,people have higher and higher requirements for food preservatives.Besides extending the shelf life of food and maintaining the original quality and nutrition of food,they are also required to have other advantages,such as green,safe,no potential toxic and side effects,and not increasing the environmental burden.Therefore,we choose to combine the packaging materials with green antibacterial active substances to achieve the preservation of food instead of adding preservatives to food to extend the shelf life of food,which can not only meet the needs of consumers for food health and safety but also reduce the environmental pollution and resource waste caused by food packaging.In this paper,the antibacterial effect of essential oil and the synergistic antibacterial effect of different essential oil combinations were studied.The composite essential oil with a better antibacterial effect was microencapsulated as the core material,and the composite essential oil microcapsules were mixed with carboxymethyl cellulose and whey protein to obtain the composite microcapsule membrane with an antibacterial effect.The shelf life of low sodium salt-cured meat can be prolonged by coating the prepared microcapsule composite membrane solution on the surface of low sodium salt-cured meat.The main conclusions are as follows:1.The four essential oils of cinnamon,oregano,galangal and bamboo leaf with good antibacterial activity against the test bacteria were screened by the filter paper sheet method and the two-fold dilution method.The combination of cinnamon and oregano essential oils was determined to have good synergistic antibacterial effect by tessellation analysis,and the best antibacterial effect could be obtained by compounding in a 6:4 volume ratio during use.The main chemical components in the combination of essential oils were analyzed by gas chromatography-mass spectrometry（GC-MS）and includedγ-pinene,linalool,trans-cinnamaldehyde,thymol and eugenol,which are the main active substances in the combination of essential oils to exert the antibacterial effect.2.At the same time,the compound essential oil was treated with different temperatures and different times ultraviolet irradiation to observe the change of antibacterial effect and analyze the thermal stability and light stability of the compound essential oil.The results showed that the compound essential oil still had a good antibacterial effect on Staphylococcus aureus and Escherichia coli under different temperature treatments and different ultraviolet irradiation at the same time.It showed that the compound essential oil did not change its properties due to the increase of composition and content,and had good stability.3.The potentials of Arabic gum and gelatin at different pH values were determined respectively,and the optimum pH of the microcapsule coacervation process was determined to be 3.0.The single factor experiment was used to determine the optimal rotational speed of essential oil dispersing in wall material solution was 10000 r/min.Based on the single-factor experiment,the best parameters of preparing composite oil microcapsule were determined by response surface analysis,which was as follows:the ratio of wall to the material was 1.06:1,the ratio of core to the wall was 1.44:1,the complex coagulation temperature was 53.40℃,the curing time was 6.44 H.In the actual experiment,according to the optimization results,the ratio of wall to the material is 1:1,the ratio of core to the wall is 1.5:1,the complex coagulation temperature is 53℃,and the curing time is 6.4 h.under these conditions,the embedding rate and yield of the composite oil microcapsules are 89.61%and 89.78%,respectively,which shows that the response surface model has a good fitting effect.4.The microcapsules prepared by response surface optimization were analyzed by scanning electron microscope（SEM）.The results showed that the microcapsules with the particle size of 20-30μm were slightly concave and irregular round.Compared with the wall material and empty capsule,the morphology of the composite oil microcapsules changed significantly.The formation of the composite oil microcapsules was verified from the side.The Fourier transform infrared（FTIR）,thermogravimetric（TG）,and differential scanning calorimetry（DSC）curves of wall material physical mixture,empty capsule,and microcapsule samples were analyzed.The results showed that the compound essential oil was successfully coated into the wall material to form a microcapsule,and the active substances in the microcapsule were well protected,and the overall structure was stable.5.Using sodium carboxymethyl cellulose and whey protein as film-forming matrix materials,based on a single-factor test,through orthogonal test and AHP subjective weighting method analysis,the optimized scheme is as follows:glycerol dosage is 0.5 m L,microcapsule particle dosage is 1.5 g,drying temperature is 40℃,the tensile strength of the microcapsule composite membrane is 18.8%The results show that the elongation at break is 61.14%,the oxygen permeability is 3.5 cm³·cm/cm²·s·PA,and the transparency is 43.79.6.The surface morphology of the blank film,essential oil film,and microencapsulated bacteriostatic film were observed under the electron microscope,and it was found that the surface of the blank film was smooth and flat;the surface of the essential oil film had more cracks and the oil droplets were aggregated but not uniformly dispersed in the matrix material;the surface of the microencapsulated composite film was rougher and slightly raised,but the overall morphology was uniform and stable.Analysis of the Fourier infrared curve and thermogravimetric curve changes of the blank film,essential oil film,and microencapsulated inhibition film,the results show that the inhibition film in the microcapsule particles uniformly distributed in the network structure of the matrix material,did not destroy the original film-forming substrate between the hydrogen bond and force,but with the formation of the film-forming matrix material to form a new force,the structure of the resulting microencapsulated inhibition film is stable,with a strong inhibition effect.7.After the microencapsulated composite film was coated on the surface of the low sodium salt bacon（A₂）,the pH,TBARS and total bacterial colony of the low sodium salt bacon showed a more moderate trend during storage compared with the blank control group A₀,indicating that the coating of the microencapsulated composite film had a preservative effect on the low sodium salt bacon;compared with group A₁,the low sodium salt bacon in the microencapsulated composite film group also did not show a significant increase at a later stage,saying that the composite essential oil in the line microencapsulation showed a better slow release effect and could achieve a longer preservative effect.