Enhancement of Hydrophobicity of Fish Skin Gelatin via Molecular Modification with Oxidized Linoleic Acid

Abstract

Fish gelatin possesses hydrophilicity in nature since it contains a few hydrophobic amino acids and a large portion of hydrophilic amino acids. Low hydrophobicity of fish gelatin results in poor water vapor barrier and water resistance of gelatin films. This can limit its usage as packaging material. To overcome this drawback, the molecular attachment of hydrophobic domains can effectively improve the hydrophobicity of fish gelatin. In this study, fish skin gelatin modified with oxidized linoleic acid (OLA) prepared under various conditions using different molar ratios of OLA/free amino group content was characterized. When OLA was prepared at 60 and 80°C for various oxidation times (0–24 h), the peroxide value (PV) increased continuously up to 9 and 12 h when reaction was performed at 80 and 60°C, respectively. Consequently, the PV decreased until the end of the reaction (24 h). Thiobarbituric acid reactive substances (TBARS) of OLA were increased sharply up to 12 h, regardless of reaction temperatures. Thus, primary and secondary lipid oxidation products mainly occurred within the first 12 h. As gelatin was modified with different OLA at various OLA/free amino group molar ratios, the one modified with OLA prepared at 60°C for 24 h at a molar ratio of 10 : 1 had the highest increases in surface hydrophobicity and carbonyl content with the coincidentally lowest free amino group content, compared with control gelatin (without OLA modification). Fourier transforms infrared (FTIR) spectra also reconfirmed the presence of fatty acid covalently attached to resulting gelatin. Therefore, OLA could be used to modify gelatin and increase its hydrophobicity.

Conjugate between hydrolyzed collagen from defatted seabass skin and epigallocatechin gallate (EGCG): characteristics, antioxidant activity and in vitro cellular bioactivity

“…Modications of protein or peptide with hydroxyl radicals (OHc) generated from redox reaction caused increasing intensities of the amide peaks. 31,32 Also, the shi to a lower wavenumber of amide II (1546 cm À1 to 1541 cm À1 ) and amide III (1254 cm À1 to 1209 cm À1 ) observed (Fig. 3a) in OHC sample might be related to interaction between OHc radical and peptides of HC via covalent bond, especially at N-H groups of peptides.…”

Ionogels Derived from Fluorinated Ionic Liquids to Enhance Aqueous Drug Solubility for Local Drug Administration

“…Besides, the hydrophobic nature of the ionic liquid would interact mainly with the hydrophobic regions of the gelatin. Likewise, the stretching vibrational modes of the C-F bonds of the CF 2 and CF 3 groups that usually appear in the spectral range between 1000 and 1300 cm −1 were found to increase the wavenumber for the Ionogels gelatin as the FIL concentration increases (1 and 5% wt not observable) that suggest an interaction between the fluorinated part of the ionic liquid with the aliphatic gelatin segment [ 78 , 79 ].…”

Synthesis and modification of poly (p‐phenylene terephthalamide) for production of light‐weight hybrid composite armors reinforced with polymer composite nanofiber mats

“…The strong band seen at 1523 cm À1 in the spectra of the CNMs corresponds to the conjugation of NH in-plane bending vibrations and C N stretching vibrations. 62,70 This signal raised as the dominant band on the spectra of the CNMs, although there is no sign of this band in the spectrum of pure PAN and its intensity is lower than the amide I band in the spectrum of BPPTA. This result supports the conversion of nitrile groups into imine (C N) groups with the formation of new hydrogen bonds.…”