Using combined optimization and vacuum freeze drying technology to prepare directed vat set starter for 'Niuganba,' a fermented beef

摘要

Niuganba (NGB), fermented beef meat, is a traditional delicacy of China. Directed vat set starters can regulate the quality and shorten the fermentation time of NGB. In this study, the Box-Behnken experiment and a single factor test were used to prepare a directed vat set starter containing Lactobacillus pentosus MT-4, Staphylococcus xylosus, and fragrant yeast for fermentation. The concentration of trehalose, mannitol, and sodium glutamate in the most effective formulation of the protective agent were 9.27%, 6.57%, and 4.73% for freeze-dried fragrant yeast, 10.66%, 6.19%, and 5.77% for the freeze-dried S. xylosus, and 10.02%, 6.19%, and 4.76% for the freeze-dried L. pentosus MT-4, respectively. Under the optimal freeze-drying conditions, the highest survival rates of fragrant yeast, S. xylosus, and L. pentosus MT-4 after freeze-drying were 89.76%, 84.46%, and 89.4%, respectively. NGB fermented using directed vat set starters required less fermentation time and had enriched flavor than traditionally fermented beef.