Technological characteristics of cold-set gelled double emulsion enriched with n-3 fatty acids: Effect of hydroxytyrosol addition and chilling storage.

A study was carried out to analyse the technological characteristics and microbiological content of gelled double emulsions (GDE) formulated with perilla oil (as lipid phase and source of n-3 fatty acids) combined or not with hydroxytyrosol (Hyt) (in the inner aqueous phase) over 30days storage at 4°C. Both the control sample without Hyt (GDE-C) and the sample containing Hyt (GDE-Hyt) had an appropriate whitish solid-like structure with rheological (elastic and viscous moduli, and phase angle) and textural (hardness and chewiness) properties of strong gels. In comparison with GDE-C, the presence of Hyt promoted the formation of weaker gels, as evidenced by lower hardness and chewiness values and elastic modulus. Overall, GDEs presented excellent water and fat binding properties irrespective of the formulation and storage time. Changes in hydroperoxides and TBARs contents over storage indicated that GDEs were little prone to oxidation after 30days. Nevertheless, Hyt increased GDE antioxidant capacity by up to 12 times after preparation, although this declined with storage. Most of the antimicrobial activity of Hyt was observed during the first two weeks of storage.