The Effects Of Polysaccharides From Dendrobiumhuoshanense On Physiological Characteristics Of Lactobacillus Acidophilus And The Application To Fermented Milk

Dendrobium huoshanense is one of the precious wild medicinal plant in China.Polysaccharides are one of the main bioactive constituents in Dendrobium huoshanense.According to modern pharmacology,polysaccharides from Dendrobium huoshanense have effect of being immune modulation,anti-tumor,anti-oxidant,hypoglycemic,and anti-cataract.Lactobacillus acidophilus is one of the most important probiotics in the intestine of the body.It has many beneficial efficacy,such as regulating intestinal microbial flora,inhibiting pathogens,enhancing immunity and reducing blood lipids.The effects of polysaccharides from Dendrobium huoshanense on the physiological metabolism of Lactobacillus acidophilus were investigated,and technology of fermented milk adding polysaccharides from Dendrobium huoshanense was optimized.1.The effect of polysaccharides from Dendrobium huoshanense on the growth of Lactobacillus acidophilus.The effect of polysaccharides from Dendrobium huoshanense on the growth of Lactobacillus acidophilus was studied.The changes of biomass,pH and utilization of reducing sugar,protein and lactic acid synthesis were analyzed at the optimum polysaccharide concentration.The kinetic model of growth and matrix consumption of Lactobacillus acidophilus was established after adding polysaccharides from Dendrobium huoshanense.The results showed that when the concentration of polysaccharides from Dendrobium huoshanense was 6 g/L,the growth of Lactobacillus acidophilus was the best,and the biomass,acid production,growth rate of Lactobacillus acidophilus were significantly improved compared with the control.At the same time,the utilization of reducing sugar and protein and lactic acid content were higher than that of the control.The fitting results of the kinetic equation and the matrix consumption kinetic equation were good.And the results showed that R2 was 0.9771 and 0.9532.2.Effects of polysaccharides from Dendrobium huoshanense on physiological correlate enzyme activities of Lactobacillus acidophilus.The enzyme activities of P-galactosidase,GOD,LDH,SOD and GSH-Px in Lactobacillus acidophilus were studied at 6 g/L polysaccharide concentration in medium.The results showed that the activity of ?-galactosidase increased by 0.8 U/mL and the activity of LDH was significantly higher than that of the control.LDH activity of the experimental group reached the maximum(65.90U/mL)at about 24h,and the control group had a maximum activity at about 36h(43.4 U/mL).The activities of SOD and GSH-Px were higher than those in the control group at each growth stage.GOD activity had a certain inhibitory effect by the addition of polysaccharides.3.Effects of polysaccharides from Dendrobium huoshanense on the tolerance of Lactobacillus acidophilus to simulated gastrointestinal environment.The hydrolysis of polysaccharides from Dendrobium huoshanense and its effect on the tolerance of Lactobacillus acidophilus in simulated gastrointestinal environment were investigated.It was found that the hydrolysis degree of polysaccharides from Dendrobium huoshanense was below 5%treated for 6 h in the simulated gastric juice and intestinal fluid,which reached the reference standard of prebiotics hydrolysis degree.Polysaccharides from Dendrobium huoshanense could effectively reduce the damage of Lactobacillus acidophilus in the gastrointestinal adverse environment and improve its survival rate.4.The optimized parameters of a fermented milk made with polysaccharides from Dendrobium huoshanense and Lactobacillus acidophilus.The concentration of polysaccharides,inoculation amount of Lactobacillus acidophilus and the fermentation time were chosen as 3 factors in single factor experiments.The optimized conditions for the fermented milk made with polysaccharides from Dendrobium huoshanense and Lactobacillus acidophilus by a L9(33)orthogonal experiments were 5 g/L of polysaccharide concentration,5%inoculation amount,14 h of fermentation time and 4%of sucrose.In this combination,milk quality was good.The acidity of fermented milk was about 88 °T,water holding capacity was 40.20%,the diacetyl content was about 13.67 ?g/mL,and the number of viable cells after ripening was about 1.2×109 cfu/mL.The changes in acidity,water holding capacity,diacetyl and viable count of fermented milk under optimal combination were investigated during the storage period.The results showed that the increase of acidity was less and the viable count was lower in the polysaccharide group than that of the control.Water holding capacity and diacetyl content change was relatively stable.Polysaccharides from Dendrobium huoshanense had a certain effect on the quality of fermented milk during the storage period.