Papers by Author: Guo Wei Shu

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 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: 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.

Abstract: This study demonstrates that the type of nitrogen sources has an important influence on the growth of Streptococcus thermophilus.at the same time ,viable counts was studied by in the medium containing various nitrogen sources (peptone, yeast extract, meat extract, tryptone，soya peptone and casein hydrolysate). The results indicated that soya peptone was the most efficient nitrogen source and and the influence of different concentrations of soya peptone on growth was determined. The results indicated that viable bacteria were stimulated by the high soya peptone concentration (30g/L).

Abstract: Four different prebiotics including fructo-oligosaccharide isomalto-oligosaccharide, inulin and xylo-oligosaccharide were screened for their effects on survival of Bifidobacterium bifidum during freeze-drying. The additions of prebiotics (v/v) were all 4%, 8%, 12%, 16% and 20%. The results showed that prebiotics could act on Bifidobacterium Bifidum. The optimum concentration of fructo-oligosaccharides (FOS) in samples for surival of Bifidobacterium bifidum was 12% and for viable count was 20％. Addition of xylo-oligosaccharides (XOS) played a significant role in promoting cell viablity when it was in low level. The optimum concentration of isomalto-oligosaccharides (IMO) for surival of Bifidobacterium bifidum was 16% and for viable count was 12％, while inulin in samples for surival and viable cell of Bifidobacterium bifidum both was 4％.

Abstract: Effect of Galaeto-oligosaccharide (GOS) and Isomalto-oligosaccharide (IMO) on growth of Lactobacillus acidophilus, Bifidobacterium longum and L. rhamnosus was studied. The addition of each substance (w/v) was 0.0%, 0.1%, 0.5%, 1.0% 1.5% and 2.0%.The methods were analyzed titratable acidity (°T), pH and enumeration that using reconstituted skim goat milk media as the control. All samples were incubated at 37 C for 18h. Results were as follows: addition of GOS has the significant inhibition on the growth of L. acidophilus and promotion on the growth of L. rhamnosus, while the effect on the growth of B. longum was not obviously. Addition of IMO could promote the growth of L. acidophilus, especially in low level. The growth of B. longum was increased with increase in IMO. While the effect on the growth of L. rhamnosus by adding IMO was inhibited and obviously in the high concentration.

Abstract: In the present study, the experiments were investigated with effecting of sucrose, lactose, glucose, maltose on survival of Lactobacillus acidophilus during freeze-drying. In order to reach sufficient numbers viable cells, so different concentrations of protective agents were designed in the experiment, which as 3%, 6%, 9%, 12% and 15%, respectively. Measuring the survival ratio of Lactobacillus acidophilus and number of viable cells after completed drying. There were significant differences in survival during freeze-drying. Results showed that the protective agent was a critical factor affecting the survival of Lactobacillus acidophilus. In the experiments, the highest survival rate was soluble starch as the protective agent, and when the protective agent as galactose the number of viable cells was largest.