Modification of pineapple starch from stem and rhizome using multiple desired response optimization and its characterization

Abstract

The aim of this study was to modify pineapple starch from stem and rhizome using multiple desired response optimization. The octenyl succinic anhydride (OSA) modification conditions of pineapple starch were conducted using a fractional factorial central composite face-centered design. The selected independent variables included OSA concentration, pH, temperature, and time, whereas the desired multiple response variables related with emulsifying properties included the degree of substitution (DS), surface tension, and enthalpy of OSA-modified pineapple starch. The experimental and predicted values for the datasets of response variables exhibited good performance. The OSA concentration was found to be the principal factor for the DS, surface tension, and enthalpy model. The optimum conditions were 24%w/w OSA, pH 7.8, reaction temperature = 37.5°C, and reaction time = 2 h with a desirability value of 0.97. Furthermore, OSA-modified pineapple starch was characterized by FTIR, XRD, DSC and SEM comparing with native pineapple starch (NS). The OSA modification of pineapple starch resulted in an increase in viscosity and a decrease in surface tension, gelatinization temperature and enthalpy. For emulsifying property evaluation, the OSA-modified pineapple starch showed higher emulsifying activity index than NS.