Starch modification and its application in Pickering emulsion stabilization: a review

This article discusses alternatives for modifying native starch through pre-treatments, with a focus on environmentally friendly methods, in order to assess how the type of modification affects the stability of Pickering emulsions. The affinity of native starch granules for aqueous and oily phases is impaired due to low steric repulsion, causing droplets to tend to aggregate. Therefore, it is essential to study the mechanisms governing the interface of emulsions. Waxy starches are the most commonly used for Pickering emulsion stabilization due to their high amylopectin content and, consequently, high crystallinity. Most of the modified starches presented in the literature in the last 5 years for Pickering emulsion stabilization involve chemical treatment with organic acids, such as octenyl succinic anhydride (OSA), which may, however, leave toxic and harmful acidic residues that are harmful to health. In this context, the article aims to broaden horizons by highlighting emerging physical techniques (thermal and non-thermal) applied in a simple and combined manner for starch modification. The use of modified starch aims to facilitate interactions between the aqueous and oily phases, thereby improving stability through enhanced interfacial and steric interactions. From future perspectives, enzymatic modification routes of native starch deserve special attention, as they are selective in attacking the amorphous zones of starch, while also respecting green chemistry.