Preparation Of Lactobacillus Plantarum X3-2B Powder And Its Application In Fermented Mutton Jerky

For this study,Lactobacillus plantarum X3-2B was used to prepare the powder,and its freeze-drying protectant formulation would be optimized by response surface methodology,which was applied to the fermented lamb jerky.The studies were grouped into a single protectant group（skim milk）,a composite protectant group（skim milk+algae）and a control group（natural fermentation）.The effects of the bacteriological powder prepared by single and compound protectants on the physicochemical indexes,volatile flavor substances and biogenic amine content of fermented dried lamb were studied in depth by gas chromatography-mass spectrometry（GC-MS）and high performance liquid chromatography（HPLC）to provide a certain data base for the preparation of fermentative bacteriological powder for commercial meat products.The results of the study are as follows.The freeze-dring protectant formulation which was optimized by single-factor test and response surface test,while the storage period of bacterial powder was determined.With the formulation that 15%skim milk powder,10%algae sugar,1:1.2 mass ratio of slime to protectant,85.58%freeze-drying survival rate;When the composite protectant freeze-drying powder was observed upon scanning electron microscopy,the overall structure that was smooth and the bacterium wrapping effect which was perfect;the powder could be stored in vacuum at 4℃for 90 d.The number of viable bacteria that could be stored was 3.1×10¹⁰CFU/g,which had a survival rate of 58.5%.The quality of fermented lamb jerky which was affected by Lactobacillus plantarum X3-2B powder.When fermented,the p H value of 4.74 was significantly lower（P<0.05）in the composite protectant group when compared to the control group.After the baking is completed,the water activity of both the single protectant group and the composite protectant group that were below 0.6 and which were significantly lower than the control group（P<0.05）;the nitrite residues and TBA values of 0.437 mg/kg and 0.12 mg/100g of the composite protectant group that were significantly lower than those of the control group（P<0.05）,The e value of the composite protectant group that was significantly higher than the other two groups（P<0.05）,the hardness of the dried meat that was significantly lower and the elasticity that was enhanced,and all the indexes of the composite protectant group which were superior to the single protectant group.After the baking is completed,51 and 47 flavor substances which were significantly more than 41 in the control group were detected in the composite protectant group and single protectant group,respectively（P<0.05）.Analysis by thermogram clustering showed that the flavor substances in the composite protectant group were dominated by 2,3-butanediol（14.766μg/g,butyl aroma）,nonanal（125.925μg/g,greasy aroma）,methyl valerate（31.130μg/g,pine aroma）,and 3-hydroxy-2-butanone（12.962μg/g,milk aroma）were predominantly expressed in the heat map and with significantly higher content than the other groups（P<0.05）,where they contributed to the overall flavor.The histamines and tyramine of fermented lamb jerky were inhibited by bacterial powder.After the baking is completed,the contents of histamine and tyramine in the composite protectant group were 1.914 mg/kg and 1.897 mg/kg,respectively,and the contents of histamine and tyramine in the single protectant group were 2.168 mg/kg and2.108 mg/kg,respectively,both of which were significantly lower than the control group（P<0.05）.