This study presents the valorization of the Gelidium sesquipedale seaweed for the development of bioactive
aerogels with interest in food packaging applications. The raw seaweed was used to extract cellulose, highly
crystalline (Xc∼70%) and high aspect ratio (∼40) nanocellulose and an agar-based extract, rich in polyphenols
and with antioxidant capacity. Subsequently, pure PVA and hybrid aerogels containing cellulose and nanocellulose
were produced by a physical cross-linking method. The presence of hydroxyl groups provided by the
high aspect ratio of nanocellulose promoted the interactions with water and facilitated the accessibility of
moisture towards the interior of the aerogels, hence generating high water sorption capacity materials.
The agar-based extract was then incorporated into selected formulations and the release in hydrophobic and
hydrophilic food simulant media was investigated. Pure PVA aerogels dissolved in aqueous media, resulting in
an immediate release of the bioactive. Interestingly, the hybrid aerogels containing cellulose and nanocellulose
preserved their integrity and provided a more gradual release. Although the hybrid aerogels presented similar
release profiles during the first 48 h, the presence of nanocellulose led to greater release values after more
prolonged times. This shows the promising properties of hybrid PVA/cellulose/nanocellulose aerogels as matrices
for the controlled release of bioactive compounds in food systems, which could be of interest for the
development of bioactive packaging structures.