High Density Culture And Drying Technology Of Lactobacillus Rhamnose Research

Lactobacillus rhamnosus LGG?Lactobacillus rhamnosus GG?is one of the most widely used probiotic strains.Currently in medicine,daily food and health care products and other major areas have been applied.However,probiotics are very fragile,resulting in the loss of activity of the strains in the processing,handling,transportation and marketing so as to reduce or even lose their original efficacy.How to obtain high vitality probiotics has always been a bottleneck in the field of probiotics.In this study,Lactobacillus Rhamnus LGG was used as an experimental strain to study the culture medium of the bacterium and the protective agent of freeze-drying.The culture medium is optimized to enable lactobacillus rhamnosus LGG to carry out high-density culture with lower cost,and the Lactobacillus rhamnosus composite freeze-drying protective agent with high freeze-drying survival rate is determined,and high-activity Lactobacillus rhamnosus powder is obtained,and the preservation activity of the bacterium is improved.On the basis of MRS medium,seven nutrition factors,such as sucrose,lactose,pumpkin juice,glucose,golden flower sunflower,flour and milk powder,were selected by single factor test.To optimize the medium of Lactobacillus rhamnoides by the determination of absorbance and number of live bacteria.Data show that milk powder,pumpkin juice and sunflower sunflower have the most obvious effect on bacteriostasis.The proportion of several substances was further optimized by single factor method,and the response surface was optimized.The results were as follows:?jinhuakui14.2%+pumpkin juice8%+milk powder2.9%?.In the optimized MRS medium fermentation broth,the colony count was higher than that of the original MRS medium fermentation broth,and the total number of LGG colonies could reach 5.3×10¹¹cfu/mL.Three kinds of protective agents,glucose,D-galactose and ascorbic acid with good freeze-drying protective effect were screened out.The orthogonal analysis of 3 factors3 level L 9?3³?was carried out for 3 kinds of protective agents obtained from single factor experiment.The results showed that the dosage of 7%glucose had the most significant effect on Lactobacillus rhamnosus as protective agent in the freeze-drying process,The compound lyophilized protectant was determined as?7%glucose+2%D-galactose+4%ascorbic acid?.The freeze-drying survival rate of Lactobacillus rhamnose reached 84%.