Pea protein isolates affected by ultrasound and NaCl used for dysphagia's texture-modified food: Rheological, gel, and structural properties

Providing texture-modified food for dysphagia patients has been one of the most effective treatment methods. The current study aimed to evaluate a specially designed commercial pea protein isolate (PPIc) -based texture-modified food by ultrasonic treatment (US, 390 W; 20 min) at different NaCl concentrations by adjusting its texture and structure. The results showed that US can improve the texture properties of PPIc within a certain range of NaCl concentration (0.03-0.6 M). The prepared PPIc samples exhibited good mastication and swallowing characteristics with proper viscosity (33.31-704.2 mPa center dot s), softness (gel strength <30 g), wetness (good solubility and water holding capacity), etc. While with ultrasonic condition at the low NaCl concentration (0.1 M), the PPIc could achieve an overall superior textural attribute than those with other salt concentrations. Further research showed that US-NaCl combination could facilitate PPIc gel to maintain a more proper dysphagia texture, not only by reducing the number of pores and unfolding structures during processing, but also by enhancing the surface area of protein particles and cross-linking interaction of proteins through more exposure of sulfhydryl groups. It was also found that the beta-turns of untreated-PPIc transformed to beta-sheets at high salt concentration, whereas inverted transformation was observed at low NaCl concentration (0.03 M). We further unveiled US significantly enhanced the solubility, water holding capacity, and gelling ability of the PPIc. Overall, US-NaCl would be a promising method for the preparation of modified textural PPIc, which provides a new approach to formulate low-salt, high-nutrition, and customizable food for special populations such as the elderly and dysphagia.