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Liposomes coated with chitosan by ionic gelation with tripolyphosphate (TPP-chitosomes) are interesting particles for stabilizing active compounds. However, the encapsulation condition must be optimized. The aim of this study was to optimize the encapsulation of phenolics and carotenoids of carrot pomace in TPP-chitosomes by using a Central Composite Design 23 and response surface methodology. The independent variables were the phospholipid (0.8–4.2 mg/mL), chitosan (2.6–9.4 mg/mL), and carrot pomace (4–14 g/100 mL of ethanol) concentrations; the responses were the encapsulation efficiency in TPP-chitosomes (EE) of phenolics, a-carotene, and b-carotene and the particle size and zeta potential of the particles. The zeta potential ranged from +17 to +37 mV, indicating that the liposomes were coated with chitosan and that the particle sizes were in the nanometric to submicrometric scale. The optimized condition for encapsulating carotenoids was 2.5 mg/mL phospholipids, 6.0 mg/mL chitosan, and 12 g of carrot pomace/100 mL of ethanol. In this condition, the EE of phenolics and α- and β-carotene was 95%, 98%, and 99%, respectively. Therefore, TPP-chitosomes containing encapsulated phenolics and carotenoids, which can be obtained from agro-industrial by-products, have potential application as natural pigments in food or cosmetics. TPP-chitosomes can also be used to encapsulate other types of natural pigments. [ABSTRACT FROM AUTHOR]

Summary: The main objective of this study was to extract phytochemicals from carrot by‐product, encapsulate them in TPP chitosomes (consisting of liposome vesicles coated with chitosan cross‐linked with sodium tripolyphosphate) and incorporate them into chitosan (Ch) films. Physicochemical, antioxidant and antimicrobial properties of films were evaluated. Three concentrations of TPP chitosome suspension were studied: 50%, 60% and 70%, designated TPPCh50, TPPCh60 and TPPCh70 respectively. Microscopy analyses showed that the particles modified the surface and internal structures of the Ch films, providing films with higher average roughness (Control: 12.6 ± 1.8 nm vs. TPPCh70: 96.1 ± 8.0 nm) and decreased gloss (Control: 34.1 ± 3.9 GU vs. TPPCh70: 5.6 ± 1.0 GU). Furthermore, the TPPCh films displayed decreased Ch intermolecular interactions, which produced less mechanically resistant (TS = 15.3 MPa), more elongable (EB = 47.9%), slightly more water‐soluble (SI = 14.7%) and more water‐vapour permeable (WVP = 7.54*10−9 g/msPa) films, mainly at high phytochemical concentration (TPPCh70) as compared to the Control. TPPCh addition in the Ch film improved its antioxidant capacity (3.6 times greater) and UV/Vis light barrier property, but no significant antimicrobial activity was observed. In conclusion, TPPCh films could be used as packaging to preserve foods that are sensitive to oxidation. [ABSTRACT FROM AUTHOR]