Study On The Production Technology Of Lactobacillus Antifungal Active Peptide Powder

The country is developing increasingly vigorously.In the food industry,from the initial solution of food and clothing to the pursuit of high standard food quality,the word "safety" has been deeply rooted in the hearts of the people.The abuse of chemical preservatives has always been the worst stubborn disease of food safety problems,which not only makes crazy attempts on the edge of breaking the law,but also seriously affects human health.In such an environment,the continuous deepening of the research on antimicrobial peptides means that relevant people have sought answers in the direction of natural preservatives.The purpose of this study is to develop a biological preservative,take a Lactobacillus ALAC-4 with broad-spectrum fungicidal properties as the research object,optimize the type and formula of natural culture medium,fermentation process and drying process,so as to prepare highly active antibacterial peptide powder,and lay a foundation for its application in food,feed and other industries.The main results are as follows:1.seven kinds of natural culture media were selected for fermentation.The whey culture medium was selected as the fermentation medium by measuring the antibacterial activity of Lactobacillus fermentation broth;After further optimization of the medium,the optimal formula of fermentation medium was determined as follows: whey 500 ml/l,water 500 ml/l,glucose 1 g/l,yeast powder 2 g/l,enzyme hydrolyzed casein 5 g/l.2.lactobacillus was inoculated with the best medium for fermentation.Through single factor test,the effects of fermentation time,fermentation temperature,initial p H value of medium and inoculation amount on the production of antibacterial substances by lactic acid bacteria were studied.On the basis of single factor experiment,response surface optimization was carried out for three parameters: fermentation time,inoculum amount and initial p H value of culture medium by box Behnken design.The results showed that the three parameters had significant effects on antibacterial substances produced by Lactobacillus,and the interaction between inoculum amount and initial p H value was strong.The regression equation was as follows: bacteriostatic circle diameter(mm)=17.10-0.31a-0.075b-0.44c+0.22ab-0.25ac+0.075bc-1.80a2-1.88b2-1.85c2.The optimum technological conditions were determined as follows: fermentation time 24 h,inoculation amount 4% and initial p H value 7.0.After verification,it was found that under this condition,the antibacterial circle of Lactobacillus producing antibacterial substances reached 17.33 mm±0.17 mm.3.the lactobacillus fermentation broth was centrifuged,concentrated and dried to prepare antifungal peptide powder.The effects of spray drying and freeze drying on the organoleptic and antibacterial properties of antimicrobial peptides powder were studied.The results showed that spray drying had the best effect,and the optimal conditions for spray drying were as follows: the atomization speed was 300 r/s,the inlet temperature was 90 ℃,and the feed flow was 1 l/h.4.the antifungal peptide obtained by the optimal process has a uniform light yellow luster;The microstructure is dry and uniform powder,loose and with good fluidity;The mixed antibacterial peptide solution has no aggregative flocs,;The flavor has frankincense flavor and unique light flavor after lactic acid bacteria fermentation,and the sensory score is 90 points.The water content is 3.4%(w/w),the bulk density is 0.30 g/ml,the solubility is 87 g/100 g,and the p H value of the solution after water dissolution is 4.5.Antibacterial peptide powder has broad-spectrum antibacterial properties and can be widely used in food processing as a biological preservative.