Table 1.

Reports of lipid-based encapsulation systems for Oleuropein (OLE) and hydroxytyrosol (HT).

Formulation	Application	Main Findings	Ref.
Liposomes
Liposomes with OLE, HT and TYR	Drug-delivery system	↑ EE% for OLE No cytotoxic effects on human chondrocyte cells	[30]
DPPC liposomes with OLE	Beverages	EE: 34% Particle size: 405 nm Stable in commercial lemonade drink over 47 days at 5 °C	[33]
Ufasomes with OLE	Claim for food application	↑ antioxidant activity of encapsulated OLE against oxidative stress induced by H2O2 on CaCo-2 cells	[34]
Liposomes with phosphatidyl-HT	Claim for food application	Particle size 85 nm; Surface charge: <−25 mV (stable liposomes)	[32]
Nanostructured lipid carriers
OLE-loaded NLC	Claim for food application	OLE leakage was not observed in the nanocarriers within the 3 months of storage Good stability of OLE-loaded NLC	[35]
Emulsions
Lipid emulsions and microemulsions	Claim for food application	Digestibility assay: ↓ Gastric lipolysis of microemulsion compared to emulsions. ↓ Effect of duodenal lipolysis by the dispersion type.	[36,37]
OLE-loaded W/O/W	Claim for food application	Emulsions were stabilised for + than 40 days of storage with ↑ hydrophobic emulsifier concentration and ↓ OLE concentration	[38]
OLE-loaded O/W	Claim for food application	Stable monodisperse oil-in-water O/W was produced when higher hydrophobic triglyceride oils are used	[39]
OLE-loaded O/W	Claim for food application	↑ stability due to the surface activity of OLE	[40]
Nano OLE-loaded W/O/W	Claim for food application	Optimum conditions for formulation: 8% WPC, 1.97% pectin and 8.74% Span 80 EE: 91%; Droplet size: 191 nm; Surface charge: −26.8 mV	[41]
O/W, W/O/W and GDE with HT and perilla oil	Claim for food applications	Emulsions structurally stable at 4 °C up to 22 days. HT losses up to 24% throughout the storage of GDE → ↓ antioxidant activity of the emulsion. No lipid oxidation during storage.	[42]
GDE with HT	Animal fat replacing	Physical properties: ↑ formation of weaker gels; no significant loss levels until 30 days; minimal changes in colour and pH of W/O/W during storage. Oxidation: systems little prone to oxidation even at 30 days. Biological activity: ↑ antioxidant and ↑ antimicrobial activity	[43]
HT in W/O/W enriched in chia oil	Meat supplementation	Presence of HT: ↑ oxidative stability: ↑ DPPH free radicals scavenging; ↑ FRAP; ↓ TBARS	[44]

EE—Encapsulated efficiency; DPPH—α-diphenyl-β-picrylhydrazyl; GDE—Gelled double emulsion; FRAP—Ferric reducing antioxidant power; HT—Hydroxytyrosol; NLC—Nanostructure lipid carriers; OLE—Oleuropein; O/W—Simple emulsion; and TBARS—Thiobarbituric acid reactive substances; TYR—Tyrosol; W/O/W—Double emulsion.