In situ starch and water modification using atmospheric plasma: Structure, functionality and in vitro digestibility

Abstract

Starch modification has become necessary to develop functional foods. Sustainable technologies like plasma-activated water (PAW) have been combined with hydrothermal treatments; however, the scaling-up process is challenging. Therefore, a simultaneous treatment of starch and water in a plasma reactor and a 24 h soaking of starch-water after the treatment were compared. The effect of the treatments on the structural, functional, and digestibility properties of starches (normal (NS), waxy (WS), and high amylose (HAS)) with different amylose/amylopectin content was assessed. The results show that simultaneous treatment mainly affected the water properties. Nevertheless, the contact time (24 h) after treatment between starch and water promoted the alteration of amylose chains, branching amylopectin molecules and hydrated crystals of HAS, increasing its rapidly (RDS) and slowly (SDS) digestible starch content. Meanwhile, in NS, the contact time favored the high re-engagement of amylose-amylopectin chains inside starch granules, significantly improving the resistant starch (RS) fraction from 31 % to 75 %.