Flax mucilage and barley beta-glucan aerogels obtained using supercritical carbon dioxide: Application as flax lignan carriers

•Barley β-glucan and flax mucilage aerogels prepared using supercritical CO2 drying•Flax mucilage aerogels had higher surface area and maintained higher % hydrogel volume.•Flax lignans were impregnated onto polysaccharide aerogels.•Polysaccharide gels dried using SCCO2 show potential for bioactive delivery.

Flax lignan, secoisolariciresinol diglucoside (SDG), has been implicated in the prevention of hormonally related cancers and other diseases. Polysaccharide aerogels, dried using supercritical carbon dioxide (SCCO2), have low densities and high porosities, making them ideal as bioactive carriers. Barley β-glucan (5%) and flax mucilage (10%) hydrogels were first converted to alcogels and then dried using SCCO2, and their characteristics were analyzed. SDG concentrate was incorporated into the gels prior to drying using several approaches. Both aerogels had low densities; however, surface area and % of hydrogel volume of mucilage (201 m2/g and 57%) were higher compared to those of β-glucan aerogel (166 m2/g and 38%). When SDG concentrate was added to the hydrated polysaccharide mixtures, regardless of the technique used, SDG contents were similar; however, the impregnation yield was less than 50%. SCCO2-dried polysaccharide aerogels show promise for use as a delivery vehicle for nutraceuticals, including flax SDG.Industrial relevanceThe functional food and nutraceutical industry is looking for ways to enhance the delivery and efficacy of various bioactive ingredients. One approach is to use aerogels as a delivery system. Use of SCCO2 for the preparation of aerogels offers the advantage of eliminating the use of organic solvents and being able to operate at relatively low temperatures to minimize the degradation of bioactives. This study demonstrates one potential application where polysaccharide aerogels are impregnated with flax lignans with the anticipation to increase bioavailability, which requires further testing.