Optimization Of Mulberry Processing Technology And Development Of A New-type Mulberry Fruit Tablet Based On Conversion By Lactic Acid Bacteria

Mulberry fruit, praised as “Folk Holy Fruit” with the effects of anti-aging, improvingvision and nourishing the skin, is one of the “best health care fruits in21stcentury”.However, mulberry fruit is easy to oxidize and go bad, relatively high in sugars and lessspecies of deep processing products, limiting its promotion. In this paper, a lactobacillusstrain named LAB-5was isolated from the yoghourt to convert sugars to lactic acid, whoseprocess was optimized by Dual Response Surface Methodology and Bayesian hierarchicalmodel to build a robust fermentation technology making glucose and fructose reducedrespectively as82%and61%. Meanwhile a new-type mulberry fruit tablet was developedwith the original nutrient structure improved and sensory characteristics increased. Theconcrete results are as below:The research was started with the yoghourt purchased as the materials and the highestcontent of lactic acid as the sieving target to a lactic acid bacteria strain named LAB-5.After purification and molecular identification of the strain LAB-5, the result showed thatthe homology of the strain’s16S rDNA was more than99%with Lactobacillus plantarum,which preliminarily revealed that the strain LAB-5was belong to the genus Lactobacillusplantarum.The best process conditions of the fermentation on mulberry fruit using the strainLAB-5were confirmed by comparing and validating the optimized results of the dualresponse surface methodology based on means and variances and the dual responses methodbased on Bayesian hierarchical mode as the fermentation time was6.85d, the fermentationtemperature was35℃and the inoculation amount was3.13%(v/v).The optimum was utilized to ferment mulberry fruit to filter the optimal models and fitequations for the processes of the cell growth, lactic acid formation and nutrientconsumption. The cell growth dynamics models of the fermentation on mulberry by LAB-5lactic acid bacteria were established as below: the first segment was Logistic model (0-2d) and the second segment was Boltzmann model (3.5-5.5d). Lactic acid production models:the first segment was Logistic model (0-4.5d) and the second model was Sgompertz model Y=13.704×exp(-exp(-21×(x-3.9)))(45-7d). Matrixes consumption models:glucose consumption (0-5d) and fructose consumptionAfter nutritional evaluation, the fermentation broth of mulberry fruit was dealt with drying to develop mulberry fruit tablet and take the sensory evaluation. The results showed that the score of the mulberry fruit sensory evaluation by the spay drying method was higher with the score of164and the nutritional evaluation of the broth before and after fermentation showed that the biotransformation process could reduce the glucose content and fructose content respectively as82%and61%, improve the contents of essential amino-acids as13.2%and maintain the contents of DNJ and anthocyanin.In this paper, a new-type mulberry fruit tablet was developed with the fermentation technology optimized by robust designs firstly in domestic and the process modeled by segment, laying a theoretical foundation of food fermentation optimization and mulberry depth development.