Papers by Author: He Chen

Abstract: Effect of biological materials including sucrose concentration and bacteria ratios on fermentation of goat yogurt was studied by measuring acidity, pH and viable counts. Sucrose concentration (v/v) was 4%, 6%, 8%, 10% and 12%. The ratios of Lactobacillus bulgaricus and Streptococcus thermophilus were 1:3, 1:2, 1:1, 2:1 and 3:1, respectively. The results were as follows: lower or higher sucrose concentration and bacteria ratios resulted in adversely influence on overall properties of goat yogurt. The optimum sucrose concentration in goat milk was 8% and bacteria ratios were 2:1, respectively.

Abstract: Effect of four emulsifiers including Tween 20, Tween 40, Tween 60 and Tween 80 on emulsifying effectiveness of phytosterol adding to milk was studied by single factor and orthogonal experiment. The concentrations of four emulsifiers were all 0.2%, 0.3%, 0.4%, 0.5%, 0.6% and 0.7%. The optimal emulsified conditions showed as follows: the optimal concentrations of Tween 20, Tween 40, Tween 60 and Tween 80 were 0.40%, 0.40%, 0.20% and 0.30%, respectively, the emulsification R reached 1.043 under the conditions mentioned above.

Abstract: Effect of hot water extract (HWE) from Fructus tribuli on growth of Lactobacillus casei, Lactobacillus reuteri, Lactobacillus rhamnosus and Lactobacillus bulgaricus with material properties was studied by measuring optical density at 600nm (OD₆₀₀) and pH using MRS media as the control. The addition of HWE (v/v) was 1%, 2%, 3%, 4% and 5%. Results were as follows: addition of HWE has the significant inhibition on growth of Lactobacillus reuteri and Lactobacillus bulgaricus and the significant promotion on growth of Lactobacillus casei and Lactobacillus rhamnosus. The optimum concentration of HWE in MRS media was 2% for Lactobacillus casei and 3% for Lactobacillus rhamnosus, respectively.

Abstract: effect of five materials including sucrose, lactose, skim milk, yeast, vitamin B₂ on survival rate of Lactobacillus bulgaricus during freeze-drying was studied by measured survival and the number of viable cells. Designed different concentrations of these different protective agents, respectively, freeze-drying perfectly and then counted the survival ratio of Lactobacillus bulgaricus and the number of viable cells. Results were as follows: addition of skim milk and yeast had significant effects while addition of vitamin B₂ had minimal impact on survival rate of Lactobacillus bulgaricus. The optimum concentration of single protective agent of Lactobacillus bulgaricus during freeze-drying was that 25% (W/V) sucrose, 20% (W/V) lactose, 25% (W/V) skim milk, 20% (W/V) yeast and 25% (W/V) vitamin B₂, respectively, and survival rate was 24.5%, 35.6%, 64.4%, 62.2%, and 16.3%.

Abstract: Effect of four materials including glycine, arginine, proline and sodium glutamate on survival of Bifidobacterium bifidum during freeze-drying was studied by measuring the viable counts of before and after freeze-drying. The addition of glycine, arginine, proline and sodium glutamate (%, w/v) were all 1.0%, 2.0%, 3.0%，4.0% and 5.0%. Results were as follows: addition of glycine, arginine, proline and sodium glutamate into B. bifidum paste could significantly improve the survival rate of B. bifidum and the number of viable cells of lyophilized powder. The optimal concentrations of glycine, arginine, proline and sodium glutamate were 4.0%, 4.0%, 3.0% and 2.0%, the survival of B. bifidum was 87.49%, 84.28%, 67.50% and 69.01%, respectively.

Abstract: Effect of MgSO₄, NaHCO₃, KH₂PO₄, K₂HPO₄ and ascorbic acid on the survival of Bifidobacterium bifidum and the number of viable cells of lyophilized powder was studied. Results were as follows: addition of MgSO₄, NaHCO₃, KH₂PO₄, K₂HPO₄ and ascorbic acid into B. bifidum paste could significantly improve the survival rate of B. bifidum and the number of viable cells of lyophilized powder. The optimal concentrations of MgSO₄, NaHCO₃, KH₂PO₄ , K₂HPO₄ and ascorbic acid were 0.20%, 0.60%, 1.80%, 1.40% and 2.20, the survival of B. bifidum was 78.31%, 77.92%, 77.80% ,79.82% and 71.62, respectively.

Abstract: Effect of NaH₂PO₄, Na₂HPO₄, MgSO₄, and Ascorbic acid on survival of Lactobacillus acidophilus was investigated before and after freeze-drying. Editing different concentrations of protective agents respectively during freeze-drying. After completion of the pilot, the survival ratio of Lactobacillus acidophilus and the number of viable cells were being measured. Results were as follows: the highest survival rate and the largest number of viable cells was Na₂HPO₄ as the protective agent.

Abstract: This study reports the encapsulation yield (EY) of B. bifidum BB28 encapsulated in different sodium alginate concentrations and in different proportion of BB28 and sodium alginate.It was studied by enumeration of viable cells after depolymerization of the capsules in 9mL trisodium citrate, followed by using MRS agar at 37°C for 48 h. The concentrations of sodium alginate was 1.5%, 2.0%, 2.5% and 3.0%.The proportion of cell suspension and sodium alginate was 1:5,1:10,1:15 and 1:20. Results were as follows: The optimum concentration of sodium alginate concentrations was 2.5% and the optimum proportion of cell suspension and sodium alginate was 1:10.

Abstract: In the present study, the experiments were investigated with the effecting of NaHCO3, KH2PO4, K2HPO4 and Sodium ascorbate on survival of Lactobacillus acidophilus during freeze-drying. Designing different concentrations of protective agents, respectively. The survival ratio of Lactobacillus acidophilus and the number of viable cells will be measured after completing drying. In the process, there were major differences between the different concentrations of protective agents in survival during freeze-drying. As the result, the protective agent was playing a key factor affecting the survival of Lactobacillus acidophilus. At present in the study of the experiments, the highest survival rate was NaHCO3 as the protective agent, and when the protective agent as K2HPO4 the number of viable cells was largest.

Abstract: Goat milk was fermented by different strains of lactic acid bacterias in anaerobic tube, strains with high angiotensin converting enzyme (ACE) inhibitory activity were screened from 28 probiotic Lactobacillus strains by the criteria of ACE inhibitory activity and pH. The results showed that 20 strains had ACE inhibitory activity and among them the activity of 4 strains were extremely high, they were Lactobacillus reuteri, Lactobacillus bulgaricus, Lactobacillus rhamnosu and Lactobacillus helveticu. In vitro experiments, the ACE inhibitory activity of goat milk fermented by these 4 strains reached 95.92%, 84.61%, 82.79% and 78.57%, respectively. After incubation, pH of them were 6.17, 3.88, 5.24 and 3.71, respectively.