Preparation Of Tartary Buckwheat Antibacterial Peptide/polysaccharide Composite Film And Its Application In Fresh-keeping Beef Mince

In this paper,bitter buckwheat powder was used as a raw material to prepare bitter buckwheat antimicrobial peptide(BAP)using aspergillus oryzae solid-state fermentation of buckwheat flour.The test results showed that the fermentation broth had good antibacterial activity against Staphylococcus aureus and E.coli.The fermentation broth was lyophilized by dialysis and then added to different membrane-forming matrices,and different composite active films were prepared by solvent evaporation.By examining the structural characterization,mechanical properties,water vapor transmission rate(WVTR),oxygen transmission rate(OTR)and antibacterial performance of composite membranes,the effects of different additive formulas and edible oil types on the performance of the composite membrane were examined.After determining the best film formulation,different plant edible oils were added and the mechanical properties,barrier properties and bacteriostatic properties were examined.Finally,the fresh-keeping effect of beef quail was studied using the prepared active compound membrane.The different formulations were studied by testing the changes of TBARS,TVB-N,color,pH value and volatile flavor substances in beef pupa for 18days at 4°C.The Effect of Composite Film on the Preservation Time of Beef Clam.The main research contents and results are as follows:1.Chitosan-Buckwheat Antibacterial Peptide Complex FilmsThe optimum formulation of the composite membrane of chitosan-buckwheat antimicrobial peptide complex films was determined by experiments:1.5%(w/v)chitosan was added to 1%(v/v)glacial acetic acid solution,and 40%(w/w)dry weight of chitosan glycerin was used as a plasticizer.Tea seed oil is 10%(v/w)dry weight of chitosan,Tween-80 is used as an emulsifier,and the addition amount is 0.2%tea seed oil(v/v),1%(w/w)dry weight of chitosan was added as a bacteriostatic active substance.600 rpm stir at room temperature for 4 hours,ultrasonic deforming for 1hour,pour into the glass plate mold and keep it horizontally,with the drying temperature of 40°C for 10 hours.After takeoff the films,the films was then placed in a desiccator containing saturated sodium chloride solution at the bottom,and the humidity was75.5%,and then balance for 24 hours.The resulting composite membrane was tested for properties,with a break Elongation of 42.18±2.48%,a tensile strength of 7.91±1.41MPa,a water vapor transmission rate of 582.42±15.37 g/m~2/day,and an oxygen transmission rate of 120.3597 ml/m~2/day.2.Starch-Buckwheat Antibacterial Peptide Complex FilmsThe optimum formulation of the starch-buckwheat antimicrobial peptide composite films was determined by experiments:2%(w/v)corn starch and 1%starch sodium octenyl succinate(w/v)were miscible,and 100°C high temperature gelatinized for 30min.After gelatinized the plasticizer glycerol was added,the amount of glycerol added is 40%(w/w)of the total dry weight of the starch.Ampicillin-bearing antibacterial peptides with a dry weight of 15%(w/w)of starch were added as antibacterial active substances.The mixture was stirred at 50°C.and 600 rpm for 30minutes and degassed by ultrasonic at 50°C.for 30 minutes.The film-forming solution was poured into a glass mold and kept horizontally,and then dried at 40°C.After removal of the film,the film was placed in a desiccator containing saturated sodium chloride solution at the bottom,and the humidity was 75.5%,and the balance was 24hours.The resulting composite film has a tensile strength of 17.69±1.59 MPa,an elongation at break of 21.88±1.21%,a water vapor transmission rate of 207.41±14.53g/m~2/day,and an oxygen transmission rate of 167.05±15.30 ml/m ~2/day.3.Pullulan-Buckwheat Antibacterial Peptide Complex FilmsThe optimum formulation of the pullulan-buckwheat antimicrobial peptide complex films was determined by experiments:3%(w/v)pullulan solution was prepared,and 40%(v/w)glycerol of the pullulan dry weight was added as the plasticizer.Buckwheat antimicrobial peptide at 15%(w/w)dry weight of pullulan was added as a bacteriostatic active substance.The mixture was stirred at room temperature at 600 rpm for 1 hour until the solution was clear and transparent and degassed by sonication at room temperature for 1 hour.The film-forming solution was poured into a glass mold and kept horizontally,and then dried at 40°C in the oven.After removal of the film,the film was placed in a desiccator containing saturated sodium chloride solution at the bottom,and the humidity was 75.5%,and the balance was 24 hours.The composite film obtained had a tensile strength of 38.67±2.84 MPa,an elongation at break of7.66±1.06%,a water vapor transmission rate of 112.88±12.84 g/m~2/day,and an oxygen transmission rate of 102.62±5.2 ml/m~2/day.4.Effect of Polysaccharide Composite Film on Preservation of ground BeefPolysaccharide films prepared using as the test group,compared to control group wrap film for commercial ground beef stored 18 days 4?preservation effect.By examining the changes in the total number of microbial colonies(MCN),total psychrophilic bacteria(PCN),volatile base nitrogen(TVB-N),lipid peroxidation(TBARS),and pH during the preservation of beef quail,In addition,the effect of different membranes on the preservation of beef quail was evaluated by comprehensive organoleptic evaluation of beef flavor substances and changes in color(C).Under the condition of refrigerating at 4°C,commercially available cling film and starch film and pullulan film can preserve ground beef for 6 days.Chitosan film without adding antibacterial peptide can extend the shelf life to 9 days.The 15%antibacterial peptide-chitosan films test group was added to extend the storage time of ground beef from 9days to 15 days.The 15%antibacterial peptide-starch films and 15%antibacterial peptide-pullulan films test group extended the shelf life to 12 days.