Optimization of the enzymatic clarification process of glucose syrups derived from agro-industrial residues

Abstract

In this work, the application of pectinase enzymes to clarify glucose syrups produced from corn fiber was studied. The enzymatic activity and kinetic parameters of the pectinase enzyme used were quantified. A specific activity of 5,528 U/mg protein, a maximum rate of 19151 U/mL, and a Michaelis-Menten constant of 1,656 mg/mL were obtained. The syrup was prepared by hydrolyzing corn fiber at 50°C and 180 rpm, and a central composite design was performed for the clarification step to find the optimal conditions of enzyme-substrate ratio and agitation. The syrup was heated to a temperature of 50°C, and an enzyme substrate ratio between 2.5 to 4.5 U/mL of syrup and agitation, varying between 215 to 285 rpm, was applied. The conditions to maximize the clarification of corn fiber syrup were determined to be an enzyme substrate ratio of 3.716 U/mL syrup and agitation of 267 rpm. These conditions were validated by taking the syrup from clarity of 65.8% to 88.1%, demonstrating that the methodology used presents advantages in the syrup clarification process. A physicochemical characterization of the corn fiber used to prepare the syrups was carried out, which presented a content of 12.90%, 23.33%, 13.4%, and 0.36% of cellulose, hemicellulose, lignin and pectin, respectively.

Keywords

• enzymatic hydrolysis
• glucose syrup
• pectin
• polygalacturonase
• enzymatic clarification