The Research Of Abandoned Porphyra Haitanensis Hydrolysate Fermention Beverage Of Lactic Acid Bacteria

Porphyra haitanensis is a kind of red algae with high protein,high dietary fiber,low fat,low calorie,rich in vitamins and minerals.It has many physiological activities such as anti-oxidation,anti-cancer and so on.It can be used to make nutritional and health food.In this study,the enzymatic hydrolysis process of Porphyra haitanensis was optimized by single factor and response test.Four kinds of lactic acid bacteria were selected to study the changes of physicochemical components and microbial indicators in the fermentation process of Lactobacillus haitanensis,and the suitable fermentation strains were selected.The fermentation technology of Lactobacillus fermented beverage was optimized.Finally,the physical and chemical properties,microbial characteristics and sensory characteristics of Lactobacillus fermented beverage stored at 4? were studied,and the tolerance of Lactobacillus to hydrochloric acid and bile salt under similar digestive conditions was evaluated.Starting with the problems in the utilization and development of Porphyra haitanensis resources in China.Lactic acid bacteria fermented beverage of Porphyra haitanensis was prepared with Porphyra haitanensis as raw material.It has not only the nutritional components of Porphyra haitanensis itself,but also the health function of live lactic acid bacteria and unique flavor of lactic acid fermentation.1.In order to achieve high value utilization of abandoned Porphyra haitanensis,enzymatic hydrolysis technique and antioxidant activity of P.haitanensis protein were studied.Single factor test and response surface optimization test were used to screen the optimal protease and enzymolysis parameters based on the index of hydrolysis degree(DH)and reducing power.The antioxidant activity of the hydrolysate was studied by determining the reducing power of hydrolysate and scavenging ability of the hydrolysate on the free radicals DPPH,·OH and O2-·.The results show that neutral protease was the optimal enzyme among the six enzymes,The optimum conditions for the hydrolysis of P.haitanensis proteins was as follows:substrate concentration 35 g·L-1,enzyme dosage 31200 U·g-1,hydrolysis temperature 46?,pH7,hydrolysis time 6.2 h;Under these conditions,DH was 31.37%,the reductive power was 2.2 and the scavenging rates for DPPH,·OH and O2-· were 56.26%,85.84%and 72.74%,respectively indicating that the P.haitanensis can be hydrolyzed by neutral protease effectively,and the hydrolysate has good antioxidant activity and application prospects.2.Lactobacillus spp.was used to ferment the enzymatic hydrolysate of Porphyra haitanensis which had fully released its effective components.Different lactic acid bacteria were added into the enzymatic hydrolysate of Porphyra haitanensis to compare the fermentation of Lactobacillus casei,Lactobacillus plantarum,Lactobacillus rhamnosus and Pediococcus pentosus to the four lactic acid bacteria.Lactobacillus plantarum is more suitable for fermentation of the hydrolysate of laver.The changes of pH value,titratable acidity,soluble solids content,total sugar,reducing sugar content and survival rate of Lactobacillus plantarum in the enzymatic hydrolysate of Porphyra haitanensis for 30 h were studied.3.The fermentation technology of Laver seaweed beverage was studied.With sensory quality and pH value as indexes,single factor and response surface methodology were used to optimize the fermentation parameters,and the main components of Porphyra beverage were analyzed.The results showed that the optimum fermentation conditions were 5.53%sucrose,18.61 h fermentation time,3.47%Lactobacillus inoculation and 92%theoretical sensory score.Three groups of parallel experiments were carried out under the optimum conditions.The sensory score of the optimized fermented laver beverage was 93,and the relative error was 1.08%.The results showed that the response surface methodology was basically consistent with the actual value,which had a certain practical value in predicting the fermentation process parameters of the laver beverage.This beverage has the aroma of laver and the sour taste of lactic acid fermentation.4.The product characteristics of fermented laver beverage were analyzed by physical and chemical methods during storage at 4 C.The pH value,titratable acidity,centrifugal precipitation rate,soluble solids,color difference value,Lactobacillus plantarum viability and sensory score of fermented laver beverage were measured regularly.The ability to tolerate bile salts and artificial digestive fluids in the digestive tract is simulated.The results showed that the microbial activity of fermented laver beverage decreased during storage at 40?,and the viable Lactobacillus plantarum number was 6.32 logCFU·mL-1 at 21 d.The centrifugal precipitation rate increased to 3.85%,pH dropped to 4.63,and the soluble solids were 12.81 Brix.There were slight changes in physical and chemical properties and color of the beverage,but these changes were not significant.The quality of the fermented laver beverage was affected by the quality of the product.The low temperature storage period of the fermented laver beverage was determined to be 21 days.The quality of the beverage was uniform,the color was bright and the taste was soft.The results showed that the fermented laver beverage had good storage characteristics at 4 0C,but the Lactobacillus plantarum beverage did not perform well in the simulated digestive tract.The critical number of viable bacteria to play their functional characteristics,bile salt tolerance is poor,can not smoothly enter the intestinal tract through the gastric environment.This experiment provides a theoretical basis for the safe storage of Lactobacillus plantarum fermented laver beverage and the intestinal tract tolerance of the bacteria.