Synergistic Treatment Strategy for Efficient Release of Reducing Sugar from Orange Peel during Acid and Enzymatic Treatment Process

Abstract

In the present study, the orange peels were hydrolyzed at 121°C, 15 psi for 15 mins, 30mins and 45 mins using sulphuric acid (H 2 SO 4 ) at concentration ranging from 2.5 to 15 %(v/v). Furthermore enzymatic treatment process was carried out by using equal amount of xylanase enzyme to acid hydrolysates after neutralization with sodium hydroxide (NaOH) at a concentration of 5% (w/v). The enzymatic process was carried out at 37°C at 180rpm and reducing sugar was measured after 1, 2 and 3 hr of enzymatic treatment. It was found that the maximum reducing sugar per gram of orange peel was found to be 315.54 mg/g in presence of 2.5% (v/v) H 2 SO 4 at 15 psi for 30 min reaction time which was considered to be optimum. The maximum reducing sugar found during enzymatic treatment was 616.81mg/g at 3rd hour, 310.19mg/g at 2nd hour and 274.50 mg/g at 1st hour respectively from the sample which was hydrolyzed by 2.5% (v/v) sulphuric acid. Since enzymatic conversion rate for production of reducing sugar from acid hydrolysates was found to be higher after one hour enzyme treatment process, therefore, it was considered to be optimum. The reducing sugar production rate was found to be decreasing at various incubation times may be due to inhibition of enzyme. Therefore, the maximum reducing sugar (582.48 mg/gm of orange peel) can be produced by optimization of acid hydrolysis and enzymatic treatment.