Abstract

Olive leaves (Olea europaea L.) are one of the main by-products generated from olive oil industry. Oleuropein (OE) is the major polyphenol described in olive leaves extracts. Encapsulation and controlled release of bioactive compounds such as polyphenols is one of the main potential applications of W1/O/W2 double emulsions (DE) in the food industry. By suitable formulation of the lipid phase, DEs could be used as fat replacers in the development of healthier or functional foods with lower content of saturated fatty acids and higher content of unsaturated fatty acids. The aim of this work was the incorporation of DEs, with a healthier fatty acids profile and an olive leave extract (OLE) encapsulated in the internal aqueous phase (W1), in meat model systems (MMS) as fat ingredient, in replacement of pork backfat. A blend of olive, linseed and fish oils (70:20:10) was used as lipid phase in DE. For comparative purposes, MMS with pork backfat, MMS with vacuum DE as fat ingredient and MMS with unencapsulated OLE were also prepared. The oxidative stability (peroxide value), antioxidant capacity (FRAP and DPPH), and OE content of the MMS were analyzed for 7 days at 60 ºC. A great oxidative stability was observed for MMS with OLE (both unencapsulated and encapsulated in W1) until day 5 of storage, showing lower peroxide values than MMS with pork backfat or vacuum DE. However, a large increase of peroxide value together with a large decrease in DPPH and FRAP values were observed for MMS with unencapsulated OLE at day 7 of storage, as a consequence of the sharply decrease that took place in the OE content. DEs rich in unsaturated fatty acids and OLE showed a high oxidative stability and antioxidant capacity, and may be used as fat replacers in the development of healthier meat products.