Development and characterization of nano-micro structures as carrier for bioactive compounds

• Main Author: Boutrup Stephansen, Karen
• Format: Book
• Language: English
• Published: National Food Institute, Technical University of Denmark 2015
• Subjects: /dk/atira/pure/sustainabledevelopmentgoals/good_health_and_well_being; SDG 3 - Good Health and Well-being; atlantic cod; Gadus morhua; North Atlantic
• Online Access: https://orbit.dtu.dk/en/publications/922a3018-13e6-4379-9dbf-d3b643269d11; https://backend.orbit.dtu.dk/ws/files/142937798/PhD_thesis_KStephansen.pdf

New biopolymers are in high demand due to their excellent biocompatibility, biodegradability, and natural origin. In this PhD project, water soluble fish sarcoplasmic proteins (FSPs) from the North Atlantic cod (Gadus morhua) have been studied as a potential new biopolymer for development of nano-micro structures. Two kinds of nano-micro structures have been explored: electrospun fibers (Paper I, Paper II, and Paper III) and self-assembled nanocomplexes (NCXs) (Paper IV). FSP was observed to be highly suitable for electrospinning. The fiber morphology varied significantly with FSP concentration, from beads to fibers. Moreover, the morphology within one FSP concentration was very diverse, as evident from the fiber diameter ranging from nanosized to micronsized (Paper I). The size distribution of the fiber diameter was decreased by removal of low molecular weight compounds (< 8 kDa). Despite the water-soluble nature of FSP, the fibers were insoluble in aquatic media (except at high sodium dodecyl sulfate concentrations) (Paper I, Paper II, and Paper III). Contact angle measurements indicated that the FSP fibers were hydrophobic, and incubation with the hydrophobic dye 8-anilino-1-naphthalenesulfonic acid (ANS), confirmed the presence of hydrophobic pockets inside or at the surface of the fibers (Paper III). Interestingly, the physical properties of the fibers significantly changed after incubation with surfactants as well as with the surfactant type; the FSP fibers were dense after incubation with cationic surfactant, whereas inner porosity of the fibers was observed after incubation with anionic or neutral surfactants. Moreover, the contact angle changed from being large for anionic surfactants, to being small for neutral and cationic surfactants. Lastly, the cationic and neutral surfactants decreased the amount of hydrophobic pockets available for dye interaction (Paper III). The inherent property of FSP as consumed food made the fibers degradable by proteolytic enzymes, and the degradation products were ...