Properties of films from fish gelatin prepared by molecular modification and direct addition of oxidized linoleic acid. (March 2019)

• Record Type: Journal Article
• Authors: Theerawitayaart, Wipawee; Prodpran, Thummanoon; Benjakul, Soottawat; Sookchoo, Pornsatit
• Is Part Of: Food hydrocolloids. Volume 88(2019)
• Page Start: 291
• Page End: 300
• Publication Date: 2019-03
• Subjects: gelatin film -- Oxidized linoleic acid -- Molecular modification -- Emulsion film; Hydrocolloids -- Periodicals; Food additives -- Periodicals; Colloïdes -- Périodiques; Aliments -- Additifs -- Périodiques; Colloids; Food additives; Periodicals; Electronic journals; 664.06
• DOI: 10.1016/j.foodhyd.2018.10.022
• Languages: English
• ISSNs: 0268-005X

Abstract

Abstract: Films prepared from fish gelatin molecularly modified via covalent attachment with oxidized linoleic acid (OLA) so called "modified gelatin (MG)" and those added with OLA (G + OLA) at various levels (10–50%, w/w, of protein) were characterized, in comparison to control film (without modification or addition with OLA). Films from MG and G + OLA had lower elastic modulus (EM), tensile strength (TS) and water-vapor permeability (WVP) but higher elongation at break (EAB) and yellowness (b*-value), as compared to control film (p < 0.05). MG film had lower WVP than G + OLA film containing OLA up to 30% (p < 0.05). Moreover, MG film possessed higher transparency and much lower yellowness without rancid smell, compared to the G + OLA films. The control and MG films exhibited similar smooth and homogenous surface and cross-section, while G + OLA films showed rough surface with distributed oil droplets. FTIR and DSC analyses revealed that incorporation of OLA via either molecular modification or direct addition to gelatin led to the decrease of gelatin-gelatin interactions and structure order. In addition, both MG and G + OLA films exhibited lower glass-transition (Tg ), melting transition (Tm ) and degradation (Td ) temperatures than the control film. Therefore, the incorporation of OLA by molecular modification and direct addition to gelatin could improve flexibility and water-vapor barrier property of gelatin-based films but slightly decrease thermal stability. Graphical abstract: Image 1 Highlights: Methods of oxidized linoleic acid (OLA) addition affected the properties of film. Water-vapor barrier property of gelatin film was enhanced by OLA incorporation. Molecular modification of gelatin with OLA improved water-vapor barrier of film. Direct OLA addition enhanced flexibility and extensibility of gelatin film.