Kinetics modelling of acid hydrolysis of cassava (Manihot esculanta Cranz) peel and its hydrolysate chemical characterisation

Abstract

Acid hydrolysis of cassava peel (CP) to reducing sugar (RS) was undertaken at 70, 90 and 110 °C, and 0.5, 1.0 and 1.5 M concentrations of H2SO4. Kinetics and thermodynamics of the study were tested for their statistical consistency using analysis of variance (ANOVA). The RS was characterised for its bioactive chemical compositions and functional groups. Maximum RS of 47.70 g/l from a 50 g/l of the CP with the highest rate constant (k) of 0.00247 min−1 was attained at 1.5 M and 110 °C. The ANOVA results of F > F crit and p < 0.05 revealed that the AC at constant temperature has a significant effect on the hydrolysis. The thermodynamic analysis revealed that the highest value of 3.06 × 103 Jmol−1 for ΔH (1.5 M and 110 °C), and the lowest value of ΔS = −7.65 × 10 Jmol−1 (0.5 M and 70 °C) were obtained. The bioactive chemical indicated the presence of compounds effective against several diseases. The functional groups obtained among others include alkanols, aldehyde, and alkanoates. Therefore, CP hydrolysis is a significant way of reducing the cost of RS as it contains essential ingredients for pharmaceutical, food and medicinal purposes.

Keywords

• Cassava
• Hydrolysis
• Kinetics
• Thermodynamic
• Reducing sugar