Study On The Production Technology Of Black Beans Natto And Stability Of Its Nattokinase Microcapsule

Thrombotic diseases have a serious impact on human life and health.Studies have shown that natto can effectively prevent and inhibit the generation and expansion of thrombi,and improve cardio-cerebrovascular function.It has received widespread attention in recent years.In this paper,black beans are used as raw materials,through screening high-activity Bacillus natto,to explore the best technology of natto fermentation,a new formula and taste product,namely black bean natto,has been developed.Exploring the fermentation process of black natto on the one hand can improve the unpleasant taste of traditional natto,and is more suitable for the eating habits of Chinese people.At the same time,take advantage of the rich black bean resources in China and its unique medicinal value,to avoid natto beans raw materials of a single situation of the market,improve the quality and diversity of natto.In order to further exert the efficacy of natto thrombolysis,this paper extracted the functional component nattokinase and prepared into microcapsules,and explored the preparation method and storage stability of the capsules.The main research contents are as follows:(1)In this paper,Bacillus natto was screened from commercially available natto,soybean and black bean by casein plate method,and the activity of strain BN-2-3 was found to be the highest among the tested strains.Therefore,the physiological and biochemical identification of strain BN-2-3 was carried out.The results indicated that the physiological and biochemical characterics were in line with those of the bacterial species Bacillus subtilis and could be used as the production strain required for fermentation.(2)The black beans natto production process uses black beans as raw materials and strictly controls the process conditions in the screening of highly active Bacillus natto BN-2-3 fermentation.The single factor experiment showed that the more significant effects on the quality of black beans natto were the cooking time,inoculation amount,fermentation temperature,and fermentation time,and the factor of soaking time had little effect on the quality.Using the black natto's comprehensive score as an indicator,the four-factor three-level orthogonalization was used to optimize the black natto fermentation process.The best results were obtained: the cooking time was 30 min,the optimal fermentation time was 18 h,and the optimal fermentation temperature was At 41°C,the optimal inoculation amount is 4%.The nattokinase activity of the black natto obtained by fermentation under this condition reaches 6116.67 U/mg,and the highest sensory score is 44.2.The content of daidzin and genistin in black natto was determined in this paper.The daidzin content was 0.049 mg/g,which was 113% higher than before fermentation.At the same time,the content of daidzin was 14% higher than that of the selected commercially available natto natto,and genistein was 32.7% higher,indicating that the black natto fermented by this process condition has better nutritional value.(3)To improve the stability of nattokinase itself,and easy deactivation features,we explore a way to improve the stability of nattokinase,the preparation of nattokinase to enteric-coated microcapsule of nattokinase.Nattokinase was embedded with sodium alginate,calcium chloride,glycerol and Eudragit L100 as main coatings,and the embedding rate of microcapsules and the recovery rate of enzyme activity under simulated human gastro-intestinal conditions were determined to find the optimal wall Material ratio.Through single-factor experiments,it was found that the four wall materials had significant effects on the embedding rate and enzyme activity recovery rate of microcapsules.Using the comprehensive score of the two parameters as the index,the process parameters were optimized using the response surface method to obtain the best results: sodium alginate 2.2%(w/v),calcium chloride 0.83%(w/v),sodium alginate and The glycerol volume ratio is 4.54,and Eudragit L100 is 5.43%(w/v).The microcapsules prepared under these conditions had good process parameters,and the entrapment efficiency and enzyme recovery were 94.06% and 95.62% respectively,which were higher than the data of single factor and response surface design.The apparent structure of microcapsules was observed by scanning electron microscopy,and the structure was found to be tight and nonporous.It was confirmed that the microcapsules could well protect nattokinase and make it play a better role in thrombolysis in humans under this process condition.Finally,the storage conditions of the prepared nattokinase microcapsules were studied,and it was found that the storage temperature had a significant effect on its stability.The cryopreservation method was recommended.This study provides conditions for effectively maintaining the stability of nattokinase,reducing wastage,and making thrombolysis more targeted and effective.