Phenolic Extracts from Vaccinium corymbosum L. Loaded in Microemulsions and Liposomes as Enhancers of Olive Oil Oxidative Stability

Natural phenolic compounds are recognized as bioactive ingredients in food but can also have a role as effective alternatives to synthetic antioxidants in stability improvement of foods prone to oxidation, such as edible oils. This study aimed at the preparation and HPLC-DAD characterization of phenolic extracts from lisccinium corymbosum L. (raw, pasteurized, freeze-dried and treated with high-intensity ultrasound), and at testing their antioxidant potential in the prevention of olive oil oxidation in the native state and encapsulated into microemulsions and liposomes systems. Water-in-oil structured microemulsions used in this study were prepared using mechanical, ultrasonic, and high pressure homogenization. Liposomes with the average size of 589.1 +/- 2.9 nm were produced with the proliposome method using commercially available phosphatidylcholine - Phospolipon 90G. The obtained results showed significant prolongation of the oxidative stability of extra virgin olive oil enriched with encapsulated blueberry phenolic extracts than with native phenolic extracts, regardless of the method used for blueberry processing. Phenolic extracts encapsulated in microemulsions had a stronger effect on the prolongation of olive oil oxidative stability in comparison with the extracts encapsulated in liposomes. The average prolongation rate of oxidative stability was 45.65% by phenolic extracts encapsulated in microemulsions prepared by mechanical homogenization (p=0.012), and 58.72% by microemulsions prepared by ultrasound homogenization (p=0.011). Phenolic extracts encapsulated in microemulsions prepared by high pressure homogenization had no effect on oil oxidative stability prolongation

Influences of freeze- and spray-drying vs. encapsulation with soy and whey proteins on gastrointestinal stability and antioxidant activity of Mediterranean aromatic herbs

The aim of the present research was to study the chemical profile of volatile and non-volatile compounds in freeze- and spray-dried oregano, thyme, sage, and rosemary as well as to study the gastrointestinal stability and the biological activity of the samples after encapsulation using two proteins (soy and whey). Chemical analysis was performed by HS-SPME/GC-MS and HPLC-PDA techniques. The antioxidant activity (FRAP, DPPH and ORAC assays) and HPLC-PDA analyses were performed before and after simulated two-phase digestion process (gastric and duodenal) using human gastrointestinal enzymes. The effect of protein carriers was depended on the plant matrix and the class of compound. Soy protein is useful for the protection of thymol and carvacrol content in thyme and the increase of the antioxidant activity of sage. Whey protein is useful for flavanols stability in all studied herbs before and after the duodenal digestive phase