Study Of The Microencapsulaton Technology Of Lactobacillus Acidophilus

With the continuous improvement of people's living standard,the awareness of health is also growing.Dairy products contain almost every essential nutrients that maintain health and growth.L.acidopholus is one of probiotics which are researched and developed in the Lactic acid bacterium at present,as thethird generation fermented lactic cultures,is an important gut microbiota.But research shows the amount of L.A in diary products is hardly to live up to the minimum amount of 10⁶ cfu/g which recommended by International Dairy Foundation.And during the fermentation process,the concentration of metabolic products will increase and will inhibit the growth of L.A.And the separation of the products during fermentation is quite complicated.All of these set a limit to the substantial application of L.A.This paper studies the microencapsulation of L.A by spray drying and impulsive electrostatic droplet technique.The main content of this study is the influence of the key operational parameters of spray drying and impulsive electrostatic droplet technique on the bacteria survival rate,diameter and membrane property and its growth condition.Some key operational parameters,such as the inlet air temperature,the feed flow rate, the ratio of the wall material are determined to some extent by the single factor analysis. Furthermore,the optimum condition of spray-drying is achieved by orthogonal experiment, including inlet air temperature of 140℃,the feed flow rate of 12.5ml/min,the ratio of 1:10 for materials gum arabic and the bacteria survival rate reaches 63%.The microcapsules prepared with 1.5%alginate,2%calcium,2g/L-3g/L Fe₃O₄,10000-12000V voltage have fine sphere,particle size and smooth surface.The embedding rate of Fe₃O₄ is 88%-91%.The microcapsules membrane is most steady when the concentration of chitosan is 3g/L,and the membrane formation time at 20 mins.The growth of L.A in microcapsules are well,the microcapsules become balck and solid after12hs culturing.The growth curve of L.A shows "S" shape,the steady stage is easily observed.The concentration of L.A between free culture and by microencapsulation is minor. There is no inhabitation effect on the growth of L.A in microcapsules.