Preparation Of Oyster Lactobacillus Fermented Beverage And Its Storage Stability Research

Oyster is the world’s first farming shellfish, and also one of China’s four majorfarming shellfish. The oyster production is increasing year by year, the consumptionof fresh, freeze-dried products, spices and other primary processing products arebasically stable. So, the exploitation of new oyster product has become an inevitabletrend.In this study, enzymatic hydrolysates of Crossostrea rivulari were used as themain raw material in lactic acid bacteria fermentation research. A kind of nutrient-rich,containing lactic acid bacteria and unique flavor beverage were made in this process.Lactobacillus bulgaricus (Lb), Streptococcus thermophilus (St) and Lactobacilluscasei (Lc) were choosed as the fermentation bacterias. The effects of the temperature,sucrose content, and inoculation amount on the growth characteristics andfermentation characteristics of the three lactic bacterias were explored in Crossostrearivulari enzymatic hydrolysates.Single factor test and orthogonal test were designed to optimize thefermentation conditions and stabilizer. A stable, good flavor and fermented beveragewas developed. Then the nutrients composition of fermented beverage, solid content,activated Lactobacillus, stability ratio and the change of acidity, storage stability ofthe beverage were discussed to extend its shelf-life in4℃.The main research contents and research results were showed as follows：1. Domestication was used to improve the growth activities of Lactobacillusbulgaricus, Streptococcus thermophilus and Lactobacillus casei in the oysterenzymatic solution. The results showed that the lag phase of Streptococcusthermophilus, Lactobacillus bulgaricus and Lactobacillus casei was shortened fromoriginally10h,14h,12h to4h,6h,4h, respectively. The advancing of thelogarithmic phase is in favor of the rapid growth of lactic acid bacteria in oysterenzyme solution.2. The growth characteristics of single bacteria in the oyster enzymatic solutionwere studied. The effects of the culture temperature, inoculation amount and sucrosecontent on the growth activity of the bacteria were researched. The results showed that the acid-producing capacity and growth activity of three kinds of lactic acidbacteria increased with the culture temperature within range of36-40℃. The optimalinoculation amount of the Lactobacillus bulgaricus, Streptococcus thermophilus andLactobacillus casei were7%(v/v),5%(v/v),5%(v/v) respectively. The optimalsucrose content of three kinds of lactic acid bacterias ranged from4%-8%(w/v). Theamount of sucrose content was not conducive to bacterial growth and acid productionat2%(w/v) and10%(w/v).3. The effects of the fermentation temperature, fermentation time, inoculationamount and sucrose aontent on the mixed culture of the three lactic bacteria (Lb:St:Lc4:2:3) were researched during the beverage processing. Results showed that theoptimum conditions of the fermentation were as follows: the temperature40℃,inoculation amount7%(v/v), sucrose content7%(w/v), fermentation time10h. Thestability of the fermentation was discussed, at the time the effects of the fermentationdrink by adding different stabilizer on its stability. The optimal determine stabilizerdosage was0.2%(w/v) xanthan gum,0.3%(w/v) pectin,0.15%(w/v) CMC. Thelactic acid beverage was uniform and stable and showed milk-white, a strongfermented flavor.4. And detected a total sugar content of5.33g/100mL, protein content0.87g/100mL,5.8%soluble solids, titratable acidity75.320T. Lactic acid lactobacilluscontent was2.4×108CFU/mL.5. The beverage was stored at4℃. The acidity, pH, solid content, stability ratioand activated lactobacillus were detected during storage. The results showed that withthe storage time, the acidity rised, pH, solid content, stability ratio and activatedlactobacillus decreased. After25days storage, the fermentation still has goodstability.