Enzymatic liquefaction of jicama (Pachyrhizus erosus) tuberous roots and characterization of the cell walls after processing

Abstract

Enzymatic liquefaction of jicama (Pachyrhizus erosus) tuberous roots increases the yields of juice. Jicama tuberous root was disintegrated by commercial pectinase (Pectinex Ultra SP-L). Juice volume, glucose and alcohol insoluble solids (AIS) were determined after enzymatic disintegration. Furthermore, remaining jicama AIS were characterized by infrared spectroscopy. AIS were destarched using amylolytic enzymes and analyzed by gas chromatography. The aim of this research was to evaluate the effect of enzymatic liquefaction of jicama tuberous root on juice volume, glucose and quantification and characterization of AIS. The highest volume of juice was 980 mL/kg tuberous root. The range for maximum glucose was 58.0 - 75.8 g/kg tuberous root and the lowest for residual AIS was in the range of 15.5-24.6 g/kg tuberous root after 10 h with 0.024 mL/g of enzyme per kg at 40 °C. Infrared spectra showed signals corresponding to low methoxylated pectic substances, proteins and starch. Destarched jicama cell walls analyzed by gas chromatograms revealed a decrease in sugars after liquefaction except in xylose, glucose and mannose which increased as a result of this process. Hydrolyzed jicama tuberous root is a good source of high glucose syrups and destarched cell walls may need enzyme rich in xylanase to reduce residue further.