Development of hempseed protein films for edible packaging in dysphagia-friendly oat-porridge: Effect of pH and thermal denaturation conditions in tailoring film properties.

In this study, hempseed protein isolate (HPI) films were developed under varying pH and thermal conditions, and evaluated as edible packaging for oat-porridge, supporting the creation of innovative dysphagia-friendly foods. The effect of pH and temperature on the properties of the film-forming solutions and the resulting films were investigated. Surface hydrophobicity and thiol content of the film-forming solutions were significantly altered, primarily by pH. Furthermore, increasing temperature in combination with extreme alkaline conditions led to increased swelling index and water vapor permeability. Tensile strength (TS) and Young's modulus (YM) decreased under high pH and temperature, whereas elongation at break (EB) was enhanced, indicating improved film flexibility under these conditions. FTIR analysis confirmed that pH and thermal denaturation induced conformational changes, specifically increasing β-sheet and decreasing α-helix content. Pearson's analysis revealed correlations between β-sheet content and the properties of the film-forming solutions (thiol content, surface hydrophobicity) and the films (primarily solubility, WVP, TS, EB). Subsequently, a proof-of-concept edible packaging application was demonstrated for an instant oat-porridge meal. Rheological analysis revealed that oat-porridge packaged with the film exhibited more shear-thinning behaviour than the meal without packaging, supporting a safer swallowing process. Sensory evaluation indicated overall acceptance of the oat-porridge packaged with the film, while its classification as Level 4 according to the International Dysphagia Diet Standardisation Initiative (IDDSI) confirmed its suitability for individuals with dysphagia. Overall, the findings indicated that denaturation conditions can be tailored to modulate HPI film properties, enabling their use as sustainable and edible packaging for texture-modified dysphagia-friendly foods.