In the present work, 5% (w/w) canola oil-in-water submicron emulsions containing sodium alginate were
investigated as b-carotene (0.05% w/w) carriers. O/w emulsions prepared via spontaneous emulsification
were Tween-80 (SA, 1 and 1.5% w/w) stabilised. Ionotropic gelation of the o/w emulsions' continuous
phase via in situ Ca2þ release, in the presence (sheared o/g emulsions) or absence (quiescent o/g
emulsions) of mechanical stirring (1000 rpm, 6 h) was conducted. b-Carotene chemical stability in both
o/w and o/g emulsions following 65 day storage periods at 4, 20 and 37 C, as well as its bioaccessibility
under in vitro oro-gastro-intestinal digestion conditions were evaluated. Oxidative degradation rates of
b-carotene ranged from 0.22 to 2.77%/day. Although Ca2þ-mediated gelation of o/w emulsions’ aqueous
phase enhanced b-carotene chemical stability, oxidative degradation rates between quiescent o/g (0.07
e1.42%/day) and sheared o/g (0.19e1.50%/day) emulsions were comparable. Based on the activation
energies of b-carotene degradation calculated by the Arrhenius kinetic model, sheared o/g emulsions
exerted the lowest storage temperature dependency, followed by the quiescent o/g and SA containing o/
w emulsions. Moderate (ca. 27%) to high (ca. 48%) bioaccessibility of b-carotene was achieved in
quiescent and sheared o/g emulsions respectively, showing no dependency on SA content. Contrarily, bcarotene
bioaccessibility was reduced from ca. 29e16% for 1 and 1.5% SA containing o/w emulsions.
Digesta micellar fractions of o/g emulsions exerted smaller lipid droplet size and lower surface tension
values compared to the SA containing o/w emulsions. Therefore, it was postulated that enhanced bcarotene
bioaccessibility in o/g emulsions was associated with their higher colloidal stability throughout
gastrointestinal passage.