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Exopolysaccharides (EPS) can not only give food a unique texture but also has antioxidant capacities. To select the medium composition that influences the yield and antioxidative activity of EPS, Plackett–Burman (PB) design was employed to appraise the effects of carbon sources, nitrogen sources, and inorganic salts on yield and DPPH free radical scavenging (DPPH-FRS) rate of EPS in MRS medium fermented by Lactobacillus fermentum B62. The result indicated that sucrose (p<0.01), peptone (p<0.01), and KH2PO4 (p<0.001) had the most distinguishing comprehensive effects on yield and DPPH-FRS rate of EPS, and fructose also had a noticeable effect on the two factors (p<0.05, p<0.001, respectively). Additionally, glucose (p<0.05), soy protein (p<0.001), yeast extract (p<0.01), KH2PO4 (p<0.001) and Ca(H2PO4)2 (p<0.001) significantly positive affect the yield of EPS. And inulin (p<0.05), tryptone (p<0.001), beef extract powder(p<0.001), NaH2PO4 (p<0.01) and C2H3NaO2 (p<0.05) significantly positive affect the DPPH-FRS rate of EPS. Within the test ranges, sucrose, fructose, peptone and KH2PO4 all showed significant positive relativity to the yield and anti-oxidative activity of EPS. [ABSTRACT FROM AUTHOR]

In order to improve the survival rate of probiotics and produce probiotic goat milk from fermented goat milk of Lactobacillus casei L61 by spray drying. Spray drying has been applied to large-scale industrial production of milk powder due to its high efficiency and low cost. However, high temperatures in spray drying can result in the loss of large numbers of probiotic.The purpose of this paper is to study the effects of eight thermal protectants including skim milk, sucrose, glucose, β-cyclodextrin, gelatin, maltodextrin, glycerol, trehalose on the survival rate and viable counts of L.casei L61 after heat treatment by the single factor experiment. All protective agents have a positive effect on increasing the survival rate of L.casei L61 (p<0.05). The results indicated that the survival rates of L.casei L61 were up to the maximum of 10.94%, 1.13%, 3.04%, 0.21%, 6.97%, 0.075, 4.71% and 0.29%, while the additions of skim milk, sucrose, glucose, β-cyclodextrin, gelatin, maltodextrin, glycerol, trehalose were 20mg/L, 10%, 7%, 15%, 1.5%, 3%, 8mL/L, 10%, respectively; the viable counts after heat treatment are 19.69, 0.81, 1.78, 0.455, 12.2, 0.12, 2.75, 0.435(×106CFU/mL), respectively. This paper provides technical a reference for the development of probiotic goat milk powder. [ABSTRACT FROM AUTHOR]