Optimization of the liquefaction and saccharification of structural polysaccharides of jicama (Pachyrhizus erosus L.) tissue by enzymatic pulping

Optimized jicama root liquefaction allows to obtain the highest weight loss and sugars content to recover by-products such as food ingredients, biofuels, organic acids, etc. Jicama (Pachyrhizus erosus L.) tissue was treated with Pectinex Ultra SP-L. Optimization of jicama liquefaction and saccharification was done using Response Surface Methodology and Response Surface Methodology-Spline. A mixture of sodium acetate buffer (AAANa) at pH 4.5 and enzyme ratio (mL/g of jicama cubes) of 0.000, 0.008, 0.012, 0.020 and 0.024 were used. Samples were incubated under shaking (150 rpm) for 0.00, 4.24, 10.00, 14.24 and 16.00 h at 40 °C. At the optimum conditions (10 h and 0.024 mL/g) the pH was 4.24, total soluble solids (°Brix) amount was 9.00, weight loss percentage was 95.82%, the total and reducing sugars liberated were 119.0 and 63.8 g/kg, respectively. Uronic acids obtained were 5.7 g/kg and polyphenols amount was 26.8 mg/kg.

► RSM and RSM-S to optimize the jicama enzymatic liquefaction/saccharification. ► Cell wall tissue hydrolysis by Pectinex Ultra SP-L. ► Time of 10 h and enzyme ratio of 0.024 mL/g lead to the highest yield of neutral and acidic sugars. ► Recovering of by-products from underutilized crops: food ingredients, biofuels, organic acids.