In-vitro-digestion and swelling kinetics of whey protein, egg white protein and sodium caseinate aerogels

Supercritically dried protein aerogels made of whey protein, egg white protein or sodium caseinate were assessed as potential transportation and protection matrices for valuable components in food, nutraceutical or pharmaceutical applications. Swelling experiments of all three types of protein aerogels showed that such systems are very stable; they do not disintegrate in aqueous media, which is a major difference to silica or polysaccharide aerogels. The aerogels were loaded with fish oil where egg white protein aerogels showed the highest loading capacity, absorbing more fish oil than their own weight. Whey protein and sodium caseinate aerogels showed good controlled release properties in the conducted in-vitro digestion experiments. More than half of the encapsulated fish oil was released during intestinal digestion, whereas only a small amount of fish oil was released during oral or gastric digestion. The most fish oil from egg white protein aerogels was released during gastric digestion and only when the gel was formed in acidic environment. Despite the high loading capacity of egg white protein aerogels, those aerogels released the smallest amount of fish oil per mass of aerogel. The best ratio of released fish oil per mass of aerogel was achieved by whey protein aerogels.