| Beef meaty peptide (BMP) is one of the main component of beef flavor, which has a good synergistic taste with sodium glutamate, can enhance the beer flavor, and has good thermal stability, suitable for the requirements of heat treatment in food industrial production. This work studied the expression of different copy number of beefy Meaty Peptide (4BMP、8BMP、12BMP、16BMP) in Pichia pastoris, with the fermentation broth without BMP and beef soup for the control respectively, Preparation of Beef Flavoring Essence by Maillard Reaction. Sensory evaluation of flavor on Beef Flavoring Essence Prepared with different copy number of BMP, Optimized Maillard reaction components and reaction conditions by single factor experiments, then selected a rich flavor of beef meat flavor peptide, and determine the optimum process conditions. Finally, analysis and identify of aroma components of products.In the research of expansion fermentation with fermentor, firstly, this study investigated BMP expression and the target protein expression levels of4copies,8copies,12copies and16copies, respectively. a three-step fermentation strategy were used for BMP expression, which include the glycerol culture phase, glycerol fed-batch culture phase and the methanol fed-batch culture phase. The glycerol fed-batch speed of15mL/L·h for4hours, which is conducive to the expression of exogenous proteins. Since the methanol fed-batch control based on dissolved oxygen, using restrictive fed methanol strategy by adjusting the feeding cycle and the pulse which can make the rate of methanol added equal to the rate of consumption, and the dissolved oxygen were controlled at10%-25%.BMP with different copy number were concentrated by hollow fiber ultrafiltration and vacuum rotary evaporator, and analyzed by SDS-PAGE and Quantity One. Determination of total protein concentration by Coomassie brilliant blue. BMP content ratio of different copy numbers in equal volume were:16BMP:12BMP:8BMP:4BMP=36.42:24.74:21.32:17.52. The beef flavor characteristic of Beef Flavoring Essence Prepared with the fermentation broth without BMP is not obvious, Meat flavor is relatively weak. The beef flavor characteristic of Beef Flavoring Essence Prepared with the beef soup is obvious, but meat flavor is relatively weak too. The beef flavor characteristic of Beef Flavoring Essence Prepared with the different copy number of beefy Meaty Peptide is obvious, and meat flavor is relatively Strong. Among, beef flavor characteristic of Beef Flavoring Essence Prepared with8BMP、12BMP、16BMP is Outstanding, more obvious meat flavor, and Weight score variance analysis showed that the three peptide producing the overall flavor of the beef Flavoring Essence was no significant difference. But the Beef flavor which was Prepared by4BMP is poor relatively,pills only to discover serious.In the study of Maillard reaction taste, Ultrafiltration to concentrate16BMP as reaction base, determine the best tasting flavor reaction formula by single factor experiments and Sensory evaluation experiments is:Beef flavor peptide ultrafiltration concentrate50.00%(V/V), water50.00%(V/V), xylose10.00%(M/V),1.00%cysteine (M/V),1.0%thiamine Su (M/V),2.00%tallow (M/V),3.75%taurine (M/V),0.70%compound amino acid (M/V),5.0%of the HVP (M/V),2.00%NaCl (M/V).Maillard reaction conditions determined by orthogonal test were:reaction time90min, the reaction temperature is100℃, initial reaction pH5.0, The Beef Flavoring Essence which was prepared by this method have flavor characteristics of the outstanding beef aroma, mellow taste, the meat feel strong, fragrant long time.Finally, the quality and quantity of flavor volatiles from cooked beef meat and maillard reaction product were ditermined by Head Space Solid Phase MicroExtraction(HS-SPME). In the retention time of50min,15volatiles were identified in the cooked beef meat, and33volatiles in the Maillard Reaction product. And there were13volatiles In the Maillard Reaction product were same as the cooked beef meat. |
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