Nanoencapsulation systems to improve solubility and antioxidant efficiency of a grape marc extract into hazelnut paste

Encapsulationof aphenolic grapemarc extract toenhanceits lipid solubilityandantioxidant efficiency forapplication as a natural preserving agent of hazelnut pastewas investigated. Three nanoemulsion based encapsulation systems were tested: an oil/water nanoemulsion; a powder obtained by maltodextrin-assisted spraydrying of the previous and an ethanol/solid–lipid nanoemulsion (the third also applied to resveratrol for comparison). All the samplesweremixedwithhazelnut paste atdifferent phenolic concentrations (from1200toless than 10 ppm of gallic acid equivalents for the original and encapsulated extracts, respectively). An accelerated shelf-life test at 60 C was carried out until 59 and 98 days (for the original and encapsulated extracts, respectively) with peroxides valuemonitoring. Paste oxidation followed a first-order kineticsmodel and was significantly inhibited by extract addition. Encapsulation improved phenolic efficiency against lipid oxidation, by increasing extract dispersability in the paste and preserving the antioxidant activity, with the oil/water nanoemulsion resulting as the best system.