Study On The Processing Of Citrus Segment Membrane Peeling With The Method Of Fermented And Enzymatic Combination

Citrus can is the main product in the citrus processing with the membrane peeling as the key procedure in citrus canning production. Currently, acid-alkali peeling is the main method that produces a large quantity of waste water containing abundant pectin, which brings great difficulty and expensive to deal with. The gradually popularized enzyme peeling method has the characteristics of high cost and COD in waste water. This article introduced a new method for citrus segment peeling, which used the waste water as fermented culture medium to produce pectinase that peeled citrus segment membrane to match the effective use of waste water and reduce cost. The results are as follows:Aspergillus niger 2214 is selected as experiment strain among all teseted strains from soil, rotten fruits and CICC (China Center of Industrial Culture Collection). Through two-stage cultivation method, the experiment showed that the optimum conditions for the strain growth are glucose concentration 2.0%, pH 5.0, temperature 30℃and the optimum conditions for ferment were segment membrane amount 30%(g/v), pH 7.0, temperature 25℃, glutin concentration 0.5%, inoculation amount of seed cultivation liquid 6% by applying single factors and orthogonal experiment. The pectinase activity could reach to 11.68x 103 U/mL under the above conditions.The rate of membrane peeling by adapting the enzyme method and acid-enzyme method is compared. The results showed that acid-enzyme method can greatly increase the rate of membrane peeling. The single and orthogonal experimental factor experiment indicates the optimal condition for citrus membrane peeling is hydrochloric acid concentration 0.2%(g/v), times 20 min, pH 6.0, temperature 45℃. The rate of membrane peeling arrived to above 90% after 33 min of dealing time with pectinase liquid under the above conditions.the feasibility about the processing of citrus segment membrane peeling with the method of fermented and enzymatic combination is investigated. Results showed that fermenting pectinase activity was higher than that original activity, the experiment can be recircled. The enzyme method and acid-alkali method was compared in their effect on the quality of citrus segment and citrus segment can and the results showed that there are little difference in the change of rigidity, rate of crash, soluble matter, Vc, color and same changing trend.