Feasibility of protein aerogel particles as food ingredient: The case of cocoa spreads

The feasibility of aerogel particles made of whey protein isolate (WP) as food ingredient was studied for the first time. To this aim, cocoa spreads, which traditionally contain large amounts of solid fat, were prepared using sunflower oil as lipid phase instead of fats. Sunflower oil was mixed with sugar, cocoa powder and WP aerogel particles or unstructured WP (control). Two preparation methodologies were applied: (i) mixing ingredients all at once (one-step) and (ii) preliminary oil absorption into aerogel particles, and subsequent mixing with the other ingredients (two-step). WP aerogel spreads showed higher viscosity than control ones, demonstrating the peculiar functionality of porous aerogel particles in entrapping oil. However, the preparation procedure drove the inter-particle interactions among ingredients. In particular, preliminary oil absorption into aerogel particles (two-step procedure) allowed a stronger network to be obtained. Results open to the possibility of applying aerogel particles as food ingredients, highlighting the need for a dedicated process design to maximise the exploitation of their functionality.