Optimization of enzyme-assisted extraction of ferulic acid from sweet corn cob by response surface methodology

Sweet corn cob (SCC), an agricultural by-product of the corn-processing industry, contains more than 80% insoluble bound ferulic acid (FA). Extraction of these bound phenolics can be achieved through chemical or enzymatic hydrolysis; however, the shift towards greener chemistry has raised awareness about the use of enzymatic hydrolysis. In the present study, the ability of ferulic acid esterase (FAE) and xylanase (XY) to catalyze the hydrolysis of FA from SCC was investigated. Response surface methodology (RSM), based on a five-level, four-factor central composite rotatable design (CCRD), was used to establish the optimum conditions for enzymatic hydrolysis of FA from SCC. Sweet corn cob was treated with a combination of FAE and XY at various concentrations (FAE: 0.00 to 0.04 U/g; XY: 0.00 to 18 093.5 U/g), temperatures (45 to 65 °C), and pH levels (pH 4.5 to 6.5).

The optimum extraction conditions predicted by the model were: FAE concentration of 0.02 U/g, XY concentration of 3475.3 U/g, extraction pH of 4.5, and an extraction temperature of 45 °C.

Under these conditions, the experimental yield of FA was 1.69 ± 0.02 g kg^-1 of SCC, which is in agreement with the value predicted by the model. © 2019 Society of Chemical Industry.