Preparation Of Aronia Melanocarpa Rupr Residue Enzyme And Its Application In Milk Tablets

The Aronia melanocarpa is mostly processed into wine and juice,and the pomace after juice extraction is usually discarded,causing not only environmental pollution but also waste.Research has shown that the pomace contains a variety of functional components,such as phenolic substances,anthocyanins and so on.In order to improve the utilization value of aronia melanocarpa pomace,this research paper takes aronia melanocarpa pomace as raw material,prepares it into enzyme liquid by two-step fermentation method,and lyophilizes it into enzyme powder,and then prepares it into enzyme milk tablet by pressing process,and the details of the research are as follows:1.Optimization of enzymatic digestion process of aronia melanocarpa pomace.Using cellulase and pectinase for enzymatic digestion of aronia melanocarpa pomace,with soluble solids content and enzymatic weight loss rate as indicators,single-way and response surface tests were conducted to determine the optimal process parameters for enzymatic digestion of aronia melanocarpa pomace by the compound enzyme:cellulase to pectinase enzyme mass ratio of 1.32:1,enzymatic digestion time of 2.20 h,and enzymatic digestion temperature of 54.81℃.In this condition,the soluble solids content was 4.27%and the weight loss rate of enzymatic digestion was 24.06%.SEM showed that the surface of the residue was rougher,with more holes and deeper holes,and some of the structures started to collapse,which further proved that the effect of enzymatic digestion by the compound enzyme was better than that by single enzyme.2.Optimization of fermentation process and antioxidant activity of aronia melanocarpa pomace enzyme.Yeast and Lactobacillus casei were selected for the fermentation of aronia melanocarpa pomace,and the optimal process parameters for yeast fermentation were determined by single-factor and response surface tests with the total phenolic content and SOD enzyme activity as indicators:yeast inoculum 0.40%,fermentation temperature 27.1℃,fermentation time 12 h,and initial brix 17.99%.Following 12 h of yeast fermentation,lactobacillus casei was inoculated with 0.30%of yeast inoculum at 37℃and left to ferment for 16 h.Afterwards,a post-fermentation was carried out at 20℃for 24 h to produce aroma in the fermentation broth.In this condition,the fermentation broth SOD enzyme activity 325.00 U/mL,total phenol content 1.981mg/mL,yeast count 2.18×108 CFU/mL,Lactobacillus casei count 7.55×107 CFU/mL,total acid 3.23 g/100 L.Under the condition,the antioxidant activity of the produced aronia melanocarpa pomace enzyme was studied,and when the concentration was 60μg/mL,the DPPH·,OH·and ABTS~+·clearance was(94.05±0.003)%,(94.11±0.018)%and(99.50±0.002)%,respectively,with a reducing power of 81.12%of that of the Vc control.3.Preparation of black fruit pomace enzyme milk tablets.The enzyme liquid was prepared into enzyme powder by vacuum freeze-drying,and the enzyme milk tablets were prepared by the tablet pressing process.The optimal formulation of the enzyme milk tablets was determined by single-factor and response surface tests as milk powder to enzyme powder mass ratio of 1:1,microcrystalline cellulose addition of 19%and xylitol addition of 14%.The resulting enzymatic milk flakes have an intact appearance,smooth surface,uniform thickness,light purple-red color,with the unique fruit flavor and milk flavor of aronia melanocarpa,sour and sweet,moderate hardness,and no sticky teeth.Mass(2.00±0.02)g/slice,moisture content(2.03±0.03)%,total phenolic content(9.73±0.13)mg/g,SOD enzyme activity(172.13±0.21)U/g,yeast count 7.42×108 CFU/g,Lactobacillus casei count 5.21×107 CUF/g,coliforms were not detected.The antioxidant activity of the produced enzyme milk tablets was studied.When the concentration of the aqueous extract of aronia melanocarpa pomace enzyme milk tablets was 0.06 g/mL,the DPPH·,OH·and ABTS~+·clearance was(96.73±0.002)%,(31.12±0.015)%and(99.95±0.002)%,and its reducing power was higher than that of the Vc control group,which was 1.09 times higher than that of the Vc control group.Results of the accelerated storage test showed that the total phenolic content of the enzyme milk tablets decreased by 6.26%,the SOD enzyme activity decreased by 3.75%,the survival rate of yeast was92.32%and the survival rate of Lactobacillus casei was 94.63%at the 28th day of storage.The survival rate of yeast was 92.32%and the survival rate of Lactobacillus casei was94.63%,which showed that the nutrient loss during storage was small,the survival rate of live bacteria was high and the stability was good.