Optimization of processing conditions of starch-based hydrogels produced by high-pressure processing (HPP) using response surface methodology

Abstract

Introduction: This study aimed to determine the optimal processing conditions to produce stable starch-based hydrogels by high-pressure processing (HPP) via response surface methodology.Methods: The experiments were carried out with different starch suspensions, namely rice, corn, wheat, and tapioca starch, at a concentration in the range of 10%–40% w/w, processed at a pressure level of 600 MPa and holding times between 5 min and 15 min. Gel formation was assessed by determining the gelatinization extent and structuring level of the samples.Results and discussion: The results demonstrated that starch/water ratio and holding time had a significant impact on gel formation in HPP treatments. Various degrees of gelatinization were observed in the treated samples due to the water absorption capacity of the starch and the molecular interactions between water and starch occurring during gelatinization. Moreover, a highly structured hydrogel formed at starch concentrations higher than 25% (w/w), whereas when starch concentration was less than 20% (w/w) lower-structured hydrogels formed, as confirmed by the values of the efficiency index measured. Completely gelatinized, highly structured, and stable HPP hydrogels were obtained from starch solutions treated at the optimized processing conditions.