Niosome-loaded cold-set whey protein hydrogels

The alpha-tocopherol-carrying niosomes with mean diameter of 5.7 mu m were fabricated and charged into a transglutaminase-cross-linked whey protein solution that was subsequently gelled with glucono delta-lactone. Encapsulation efficiency of alpha-tocopherol within niosomes was approximate to 80% and encapsulation did not influence the radical scavenging activity of alpha-tocopherol. Fourier transform infrared (FTIR) spectroscopy suggested formation of epsilon-(gamma-glutamyl) lysine cross-linkages by transglutaminase and that enzymatic cross-linking increased proteins hydrophobicity. FTIR also proposed hydrogen bonding between niosomes and proteins. Dynamic rheometry indicated that transglutaminase cross-linking and niosomes charging of the protein solution enhanced the gelation process. However, charging the cross-linked protein solution with niosomal suspension resulted in lower elastic modulus (C) of the subsequently formed gel compared with both non-cross-linked niosome-loaded and cross-linked niosome-free counterparts. Electron microscopy indicated a discontinuous network for the niosome-loaded cross-linked sample. Niosome loading into the protein gel matrix increased its swelling extent in the enzyme-free simulated gastric fluid. (C) 2015 Elsevier Ltd. All rights reserved.