Gelatinization and Retrogradation Properties of Native and Hydroxypropylated Crosslinked Tapioca Starches with Added Sucrose and Sodium Chloride

This study investigates how the addition of sucrose and sodium chloride influences the thermal properties of native and modified tapioca starches. Specifically, the researchers examine hydroxypropylated crosslinked tapioca starch, a common food ingredient used for its stability and texture-modifying capabilities. By using Differential Scanning Calorimetry (DSC), the authors measured changes in gelatinization and retrogradation to understand how these common food additives affect starch behavior during processing and storage.

The researchers compared native tapioca starch with two types of hydroxypropylated crosslinked tapioca starch (varying in degree of substitution). They prepared starch slurries with different concentrations of sucrose and sodium chloride (5% and 10%) and analyzed them using DSC. Gelatinization was assessed by heating the samples, while retrogradation was evaluated by measuring the enthalpy of starch gels after storage at 4°C for up to 26 days. This allowed the team to quantify the impact of solutes on the crystalline structure and stability of the starch.

The study found that hydroxypropylated crosslinked starches have lower gelatinization temperatures and enthalpies than native starch, likely due to the disruption of crystalline regions by the hydroxypropyl groups. Adding sucrose or sodium chloride consistently increased the gelatinization temperatures of all starch samples, as these solutes compete for water and stabilize the starch structure. Regarding retrogradation, the modified starches showed significantly less recrystallization than native starch. While sucrose had a negligible effect on retrogradation, sodium chloride proved highly effective at inhibiting it, with 10% NaCl completely preventing detectable retrogradation in the modified starch samples over the 26-day storage period.

Understanding how common food ingredients like salt and sugar interact with modified starches is critical for the food industry. These additives are ubiquitous in sauces and processed foods, and their ability to alter starch gelatinization and retrogradation directly impacts product texture, shelf-life, and stability. This research provides practical data for food technologists to optimize formulations for products that require specific viscosity and resistance to staling.