Fermentation Characteristics For Lactic Acid Bacteria In Dendrobium Officinale Juice And Preparation Of Beverage With Lactic Acid Bacteria

Dendrobium officinale is a valuable Chinese herbal medicine,It mainly contains polysaccharides,alkaloids,phenols,amino acid,microelement and other active ingredients.The results showed in modern research that it had effects of lowering blood sugar,inhibiting tumor cells,resisting physical aging,enhancing human immunity,relieving fatigue,etc.In this paper,the lactic acid bacteria fermentation characteristics of Dendrobium officinale juice were studied,and lactic acid bacteria beverage of Dendrobium officinale juice was prepared.During the fermentation process,the composition changes of Dendrobium officinale juice were studied,the changes of antioxidant properties were analyzed,and the quality changes of the beverage during storage were evaluated.The main research results were as follows:(1)Fermentation characteristics and kinetics of lactic acid bacteria in Dendrobium officinale juice.The fermentation characteristics of Dendrobium officinale juice were studied by Lactobacillus acidophilus,Lactobacillus casei and compound lactic acid bacteria(Lactobacillus acidophilus,Lactobacillus casei).The results showed that the compound lactic acid bacteria was more suitable for Dendrobium officinale juice.When the fermentation time was 12h,the biomass of compound lactic acid bacteria reached 9.56×107cfu/mL,lactic acid of the fermentation medium was 0.98mg/mL,and the pH of the fermentation medium was 3.6.The characteristics of cell growth,product formation and substrate consumption in the fermentation process of Dendrobium officinale juice lactic acid bacteria were studied,and the fermentation kinetics model of Dendrobium officinale juice lactic acid bacteria was established,which laid the foundation for subsequent experiments.The following were fermentation kinetics model:Kinetic model of cell growth:X(t)=112.696e0.513t/106.455+1.048e0.513tKinetic model of product synthesis:P(t)=0.417+0.06(X(t)-1.048)-0.208 ln(106.455+1.048e0.513t/107.503)Kinetic model of substrate consumption:S(t)=5.226-0.029X(t)-0.029 ln(106.455+1.048e0.513t/107.50)(2)Optimization of lactic acid bacteria fermentation process of Dendrobium officinale juice and preparation of beverageThe suitable fermentation process was as follows:fermentation time 12h,temperature 37?,inoculum 3%.The suitable proportion of auxiliary materials was as follows:sucrose 6%,vitamin C 0.03%,citric acid 0.01%,pectin 0.01%.(3)Changes of main components and antioxidant activity of Dendrobium officinale juice during fermentationThe polysaccharide concentration reduced 19.6%,and the polyphenol concentration remained fairly constant in fermentation mediumABTS radical and DPPH radical scavenging rate enhanced 22.9%and 21.3%,respectively.The reducing power improved 0.306.(4)Quality change of lactic acid bacteria beverage with Dendrobium officinale juice during storageThe quality changes of the beverage stored at 4?:after 25 days,the biomass of lactic acid bacteria in the beverage was 1.23×108cfu/mL.The ABTS radical and DPPH radical scavenging rate of beverage reduced 13.1%and 15.7%,respectively.The reducing power of beverage reduced 0.393.The beverage had good taste,fermented aroma,light yellow color and no sediment.The sensory score of beverage reduced 14.9 points.The quality change of the beverage stored at 25?:after 25 days,the biomass of lactic acid bacteria in the beverage was 4.26×104cfu/mL.The ABTS and DPPH radical scavenging rate of beverage reduced 43.3%and 57.2%,respectively.The reducing power of beverage decreased by 0.718.The beverage had sour taste,sour smell,dim color and white sediment.The sensory score reduced 55.8 points.