Reinforced swallowing and anti-digestive performance of lotus root starch-whey isolate protein gel via weakening effect of xanthan gum

Abstract

To develop dysphagia-friendly, high-protein foods, this study selected xanthan gum (XG) as a texture modifier in a lotus root starch-whey protein isolate (LRS-WPI) composite system. According to the International Dysphagia Diet Standardization Initiative (IDDSI) framework, the incorporation of XG reduced the texture level of LRS-WPI gels from level 7 to level 4, enhancing their suitability for dysphagia patients. However, low addition-XG (0.05 %–0.10 %) promoted macromolecular clustering (≥1000 μm) through bridging interactions with WPI, which might not be conducive to the comfort of the swallowing process. While higher XG content increased gel viscosity beyond 600 cp and minimized oral friction, demonstrating its potential to prevent choking. During co-heating, XG raised the pasting temperature by approximately 10 °C and reduced amylose leaching. In vitro digestion revealed that 0.60 % XG reduced rapidly digestible starch by 30.07 % compared to the LRS. Results of water migration, intermolecular interactions, and microstructure suggested that XG disrupted the WPI gel network via hydrogen bonding and electrostatic interactions, and acted as a “lubricant” through self-assembled flexible gels. Additionally, XG hindered LRS digestion by constructing a physical barrier and competing for water. This article would offer valuable insights into improving the friendliness of high-protein dysphagia foods.