Studies On The Macerating Enzyme Applied To The Process Of Fruits And Vegetables

The new enzyme(macerating enzyme)applied to the process of fruits and vegetables was studied in this paper. Macerating enzyme was produced by Aspergillus niger through solid-state fermentation, which included Pectinase, CMCase, Xylanase, Glucoamylase and Proteinase.This paper included four parts: the breeding of high pectinase production strain, the optimization of fermentation condition, the study of the optimal reactive condition of macerating enzyme and the application of macerating enzyme in the processing of fruits and vegetables, the study of pilot culturing of macerating enzyme.Aspergillus niger strain 28 was treated by Microwave and UV mutation. The mutant strain MU35 obtained through Microwave and UV treatment was incubated in solid-state medium. The activity of Pectinase increased by 60% and reached 230 U/mL. Through propagate test, the character of enzyme production of strain MU35 was stable.The effect of nutrient and culturing condition on enzyme production of strain MU35 was studied. Through the change of nutrient and culturing condition, the composition of macerating enzyme was analysed.The optimal reactive temperature and pH of macerating enzyme were as following: Pectinase, CMCase, and Xylanase, were 50 ℃,60 ℃, 50 ℃, and 4.5,3.6,4.0, respectively.The application of macerating enzymes in the processing of fruits and vegetables was studied. The results showed that macerating enzyme could improve the rate of juice extracting and clarification in different degree. At the same time, the amount of soluble materials were also increased. In the processing of apple, the optimal decomposing condition of macerating enzyme was as following: enzyme addition 15 U/g apple meal, enzyme processing time 0.5 h , processing temperature 30 ℃;The optimal clarifying condition of macerating enzyme was as following: processing temperature 40 ℃, enzyme addition 15 U/g juice, pH 3;In the processing of cushaw, the optimal condition of macerating enzyme was as following: the enzyme addition 15 U/g cushaw meal, enzyme processing time 1 h , processing temperature 40 ℃.The pilot fermentation of macerating enzyme and the effect of nutrient and culturing condition on enzyme production were studied. The optimal fermentation condition in the koji case was as following : bran 200 g, bean cake powder 50 g, straw powder 10 g, Glucose 10 g, NH₄Cl 5 g, CaCl₂ 10 g, ratio of solid medium and water 1:1.4, amount of seed 10%, culturing temperature 30 ℃,culturing time 84 h. Under the optimal condition, the koji activity of Pectinase, CMCase, Xylanase, were 9858.9 U/g, 201.4 U/g, 4433.3 U/g, respectively.