Plant-based bigels for delivery of bioactive compounds: Influence of hydrogel:oleogel ratio and protein concentration on their physicochemical properties

Bigels are a class of soft matter systems with high potential in food industry as fortified ingredient replacers or food analogs. The aim of this work was to develop plant-based bigels using potato protein-based hydrogel and candelilla wax-based oleogel. The potato protein concentration and hydrogel:oleogel ratio effects on bigels production was assessed in terms of textural and rheological properties. The incorporation of curcumin and its bioaccessibility after in vitro digestion was also evaluated. All samples presented an oleogel-in-hydrogel structure arrangement. Increasing the protein concentration led to increased hardness and G*, improving the structure and consistency of bigels. The increase of oleogel fraction altered the distribution of oleogel droplets in the hydrogel matrix, affecting the hardness and the consistency of bigels. Overall, the increase of oleogel fraction and protein concentration allowed forming bigels with stronger mechanical properties and higher thermal resistance. The bigel showed a curcumin's bioaccessibility of 16.3 % and a curcumin's stability of 43.8 %, suggesting that this type of structures is promising for the delivery of bioactive compounds at the colon or for slow release of bioactive compounds. Overall, the results showed the possibility to develop potato protein-based bigels with interesting mechanical, rheological and thermal properties by changing the protein concentration and hydrogel:oleogel ratio, expanding the application of bigels in novel food products with high nutritional value and protein content, namely plant-based products.