Study On The Effect Of Dendrobium Candidum On The Fermentation Characteristics Of Probiotics

In recent years,compound fermented probiotic beverage produced by different processing methods are very popular with the customers.Plant polysaccharides not only promote the growth of probiotics but also increase the active ingredients of the product.Therefore,making a study on using the active ingredients of dendrobium officinale to promote the growth of probiotics and developing probiotic fermented milk beverage rich in dendrobium officinale has better market potentials.At present,there is no report on the study of dendrobium candidum live bacteria fermented milk beverage on the market.This research studied the impact of dendrobium candidum on the fermentation characteristics of common probiotics,and confirmed that the probiotics with a good fermentation effect after adding dendrobium candidum.Then the impact of dendrobium candidum treatment mode on probiotic fermentation was studied.On this basis,taking dendrobium candidum and dried skim milk as the main raw material,and through the probiotic fermentation,single factor experiment,orthogonal experiment and response surface method were adopted to optimize the process and formula of dendrobium candidum fermented milk beverage.Then an active probiotics dendrobium candidum fermented milk beverage with suitable sour and sweet and refreshing taste was researched and developed,and specific research results are as follows:(1)In this study,three probiotics including Lactobacillus acidophilus,Lactobacillus rhamnosus and Lactobacillus casei,were used as study objects to investigate the impact of dendrobium candidum at different fermentation temperatures on the fermentation speed of probiotics and the number of viable bacteria in the fermentation broth.The research results indicated that the lactobacillus rhamnose grew better in the fermented liquid added to dendrobium candidum.When the fermentation temperature is 40?,after 48 hours of fermentation,the number of viable bacteria in the fermented liquid is 8.00×109CFU/mL,the titration acidity is 210.6°T,and pH value is 3.812.After the lactobacillus acidophilus fermented in the fermented liquid containing dendrobium candidum at 43?for 72 hours,the number of viable bacteria in the fermented liquid was 5.00×10~8CFU/mL.After lactobacillus casei fermented in the fermented liquid containing dendrobium candidum at 37?for 72hours,the number of viable bacteria in the fermented liquid was 3.50×10~9 CFU/mL.Through comparative analysis,lactobacillus rhamnosus was identified as the fermentation strain for the follow-up study.(2)This research studied the impact of four treatment methods on of the fermentation of lactobacillus rhamnosus,including extracting liquid supernatant of dendrobium candidum juice,residues after dejuicing of dendrobium candidum,removing peel,cooking and juicing and cooking and juicing without removing peel.The test results showed that the iquid supernatant of dendrobium candidum juice had an obvious impact on probiotics(p<0.05).The number of living bacterium in lactobacillus rhamnose fermented liquid after adding liquid supernatant was 8.90×10~9 CFU/mL;the number of living bacterium in the fermented liquid after adding residues after dejuicing of dendrobium candidum was 8.90×10~9CFU/mL;the number of living bacterium in the fermented liquid after adding peeled cooking juice was2.75×10~9 CFU/mL;the number of living bacterium in the fermented liquid after adding unpeeled cooking juice was 3.78×10~9CFU/mL.Therefore,the liquid supernatant of dendrobium candidum juice was the best treatment method.Later,the impact of different solid-liquid ratio of dendrobium candidum on the fermentation liquor was further studied,and the acidity,pH value,viable count and crude polysaccharide content of the fermentation broth were regarded as evaluation indexes.The results showed that when the heating time was 10 minutes and the solid-liquid ratio of dendrobium candidum was 1:30,it had a significant impact on the number of live bacteria and the content of crude polysaccharide in the fermentation broth of lactobacillus rhizome(p<0.05).At this point,the number of live bacteria was 7.6×10~9 CFU/mL,and the content of crude polysaccharide was 60.64 mg/100g.(3)The technological conditions of dendrobium candidums probiotic fermented milk were studied.Meanwhile,this paper also studied the impact of the amount of defatted milk powder,dendrobium candidum juice,inoculation amount,fermentation temperature and glucose additive amount on dendrobium candidum fermented milk,and the acidity,pH value and the number of viable bacteria were regarded as the evaluation indexes.Finally,through orthogonal experiment,the optimum process parameters of dendrobium candidum fermented milk were obtained:consumption of dried skim milk:12%;additive amount of dendrobium candidum fermented milk:20%;inoculum size:6%;fermentation temperature:40?.At this point,the number of living bacterium of dendrobium candidum fermented milk was8.87×10~9CFU/mL,acidity was 207.33°T,and pH value was 3.440.(4)The stability of dendrobium candidum fermented milk beverage was studied,and then the impact of sodium carboxymethyl cellulose,pectin,soybean polysaccharides,xanthan gum and other stabilizer monomer on the stability of probiotic beverages was also studied.Based on this,pectin,sodium carboxymethyl cellulose and soybean polysaccharides with a larger impact were selected to carry out the response surface method to determine the best stabilizer formula.The test results showed that the stability and sensory scores of dendrobium candidum fermented milk beverage were better when the addition amount of monomer stabilizer was 0.25%.Finally,the response surface test was adopted to obtain the compound formula of the best stabilizer of dendrobium candidum fermented milk beverage:the addition amount of pectin was 0.063%;sodium carboxymethyl cellulose was 0.063%;and soybean polysaccharide was 0.063%.(5)The solid-phase microextraction-gas chromatography-mass spectrometry technology was used to analyze the control group and volatile flavor components of dendrobium candidum fermented milk beverage,and the results indicated that the relative control of volatile components were esters(33.40%),acid(45.70%),ketone(78.57%),aldehyde(96.76%),alcohol(55.17%),etc.The relative content of volatile components in dendrobium candidum fermented milk beverage were acid(57.13%in total),ketone(5.38%in total),aldehyde(17.12%in total),ester(3.75%in total)and alcohol(4.98%in total).Compared with the control group,the relative content of ketones,alcohols and esters compounds showed a significant downtrend.But the variety of flavor components increased.However,these fermented milk beverages have complex flavor components,which provide reference value for the production of high-quality dendrobium candidum fermented milk beverages.