Highly stable carotenoid-loaded SUPRAS-NLCs from carrot peel stabilize carotenoids in yogurt

Abstract

Carrot peels are a natural source of carotenoids (α- and β-carotene, lycopene and lutein) and are produced annually in significant amounts (∼5.3 million tonnes). However, their value as ingredient in functional foods faces major challenges, mainly related to the low efficiency and high costs of carotenoids extraction from peels, and their fast degradation into the fortified food. In this research, nanocapsules of SUPRAS-NLCs (supramolecular solvent-nanostructured lipid carriers) loaded with carotenoids extracted from carrot peels were incorporated into yogurt, and their potential as functional ingredients was evaluated. SUPRAS made up of octanoic acid were used to efficiently extract the carotenoids from carrot peels, and the SUPRAS extracts were subsequently used for NLC production. Yogurt was fortified with carotenoid-loaded SUPRAS-NLCs (16.5 %, v/v) and its physicochemical properties were evaluated during a storage time of 28 days at 4 °C. The pH, titratable acidity and syneresis of the fortified yogurt (NLCs-Y) showed the same behaviour as the control yogurt (C-Y), so the addition of SUPRAS-NLCs had no effect on these properties. Colour, texture and viscosity remained stable over 28 days in NLCs-Y, while pH and titratable acidity followed the same trends as the control, confiming no negative effects on physicochemical properties of the yogurt. In addition, the morphology of the nanoparticles remained unchanged. The most valuable feature of the SUPRAS-NLCs was the high stability of the encapsulated carotenoids; only around 0.2–2.8 % were lost during yogurt storage. Thus, SUPRAS-NLCs are positioned as a great alternative for the encapsulation of carotenoids and their subsequent incorporation into food matrices.