Study On The Preparation Technology Of Blueberry Pomace Leaven

Recent years, blueberry industry is developing rapidly. All kinds of new blueberry products are constantly emerging. Blueberry fruit wine production process will produce a large number of pomace, which still contains much nutrients, the majority of blueberry pomace were disposed as garbage in traditional way. Which not only result in the waste of resources, and damage to the environment at the same time. With the rapid development of blueberry wine industry, blueberry pomace on environmental pressure will increase. But if they are further processed into blueberry pomace leaven, the economic value is greatly improved. To solve the above problem, this thesis taken blueberry paste as main material to producing blueberry pomace leaven using compound enzyme degrading, microbial fermentation and vacuum freezing drying etc.In this experiment, blueberry pomace leaven fermentation research and process optimization was studied. Firstly the main component of blueberry pomace was analyzed and the condition of hemicellulose, cellulase and pectinase degrading blueberry pomace were investigated. Follow with yeast and lactobacillus casei compound fermentation. Concentrated fermentation broth made blueberry pomace leaven powder products by vacuum freezing drying. The main results of this research are as follows:1. According to the mensuration, the moisture content of blueberry pomace was 76.20%, the content of Cellulose was 13.32%, hemicellulose content was 6.53%. In addition, blueberry pomace also contains a number of protein, fat and carbohydrates, etc. The metallic element content of blueberry pomace is measured by methods of ICP-AES. The content of potassium, sodium, calcium, iron, zinc, phosphorus, magnesium, germanium and other major and trace elements were rich in blueberry pomace. In particular, Fe, Zn and other trace elements benefit to the human body are rich in content. By spectrophotometric method, pH differential method to measure total phenol and total anthocyanins content were 2.98 mg/g,1.47 mg/g.2. Using β-glucan enzyme, xylanase and cellulase and pectinase enzymolysis blueberries pomace, By enzymatic hydrolysis, make the hydrolysis of large molecules into small molecules that make microbes and human body easy to use. The optimal technology using compound enzyme degrading blueberry pomace is as following:pH5, blueberry pomace: water=1:3, the temperature is 55℃, fermentation time is 240 min. The amount of enzyme added as follows:1% cellulose enzymatic, according to 1:2 ratio the amount of p-glucan and xylanase enzyme quantity was 0.50%,0.50% pectinase enzyme. After this process, the enzymatic hydrolysis rate was 63.50%, the soluble solids content was 6.77% in enzymatic solution.3. Yeast and lactobacillus casei compound fermentation. Selected Yeast and Lactobacillus casei inoculation percentage, fermentation temperature, initial pH, fermentation time as the main technological parameter, analyze its effects on the number of yeast, proteinase activity and the number of Lactobacillus casei. The single factor experiment method and the orthogonal experiment were applied for design the test of optimization of technical parameters. The optimum processing parameters of Yeast fermentation were as follows:pH3.5, fermentation temperature 30℃,inoculate 0.15% yeast, fermented for 16h. then under the conditions of 37℃, pH4.0, add 0.5% Lactobacillus casei of inoculation percentage, fermentation time 24h, finally controlling temperature was 18～20℃ for 24h to make fragrance in fermentation broth. Concentrated fermentation broth made blueberry pomace leaven powder products by vacuum freezing drying. In such conditions of fermentation, the number of lactobacillus casei was 8.05×108CFU/mL, the activity of protease was 2525.3U/g.4. The soluble solids content of fermentation liquid was concentrated to 30%, blueberry pomace leaven powder was obtained by vacuum freeze drying, water content less than 5%. Vacuum freeze drying conditions:freezing temperature was 20℃, vacuum degree for 10 to 20 pa, cold trap temperature was 45℃.After vacuum freeze drying, the quality indexes of blueberry fruit residue enzyme products are as follows,color and lustre:blue purple, shiny, and color-uniform; Bouquet:has a blueberry fruit fragrance, aroma accompanied by fermentation; Acidity:acidity is pure, persistent stimulation; Organization form:loose without aggregation.Moisture content is less than or equal to 5%, protease content is more than or equal to (3675±10)U/g, superoxide dismutase (SOD) content is more than or equal to (515±10)U/g, lipase content is more than or equal to (45±5)U/g, the number of Lactobacillus casei greater than or equal to (8.5±0.5) ×108CFU/g.