Impact of starch-hydrocolloid interaction on pasting properties and enzymatic hydrolysis

Abstract

Hydrocolloids are extensively used for food processing because their techno functional properties (emulsifier, stabilizer, and structural agent). But there is increasing interest in their role connected with nutritional improvements, particularly related to starch hydrolysis rates, which might involve the viscosity resulting from starch-hydrocolloid interaction. The objective of this research was to investigate the impact of gels viscosity on the enzymatic hydrolysis of a range of starch gels made with different starches and hydrocolloids. Heterogeneous systems (starch-hydrocolloid) were prepared with several starches (corn, wheat, rice, potato, cassava, pea) and hydrocolloids (locust bean gum, guar gum, xanthan gum, hydroxypropylmethylcellulose K4M, psyllium) at different concentrations (0%–0.5% - 2.5%). The starch-hydrocolloid pasting behavior and their susceptibility to amylase hydrolysis was recorded with the Rapid Viscoanalyzer following a rapid method (Santamaria, Montes, Garzon, Moreira, & Rosell, 2022a). The viscosity decay due to alpha-amylase activity was modeled to obtain starch gels hydrolysis rate (k). A negative correlation was found among kinetic constant (k) and viscosity at 37 °C (r = −0.55), setback (r = −0.50), and area under the pasting curve (r = −0.42). For instance, xanthan gum and psyllium addition showed strong negative correlation between kinetic constant and viscosity at 37 °C (r = −0.75) and setback (r = −0.79), respectively, particularly when blended with potato starch. These correlations indicate that pasting properties of the starch-hydrocolloid systems might be predictors of the enzymatic digestion rate of the gels, allowing the design of foods with controlled postprandial glucose response.