Synthesis and characterization of Acacia lignin-gelatin film for its possible application in food packaging

Abstract

Background:The aim of the present investigation was to develop Acacia lignin-gelatin (LG) blended films using glycerol as plasticizer and to establish correlation between lignin contents and structure, thermal and mechanical properties of the film. Acacia lignin extracted by alkali method was used for the preparation of LG blended films by solution casting method.Results: Solubility and swelling tests of the films concluded that the lignin incorporation reduced water affinity of film. Lignin incorporation produces a noticeable plasticizing effect on the blended film, showing optimum values for film incorporated with 20 and 30 % (w/v) lignin, as deduced from their mechanical and thermal properties. Lignin blended film had lower glass transition temperatures (T g ) as compared to control gelatin. Infrared spectroscopy (FTIR) analysis of films suggested that lignin interacts with gelatin by hydrogen bonding and hydrophobic interaction consequently creating conformational changes. Atomic force microscopic (AFM) study displays smooth surface of synthesized films. Light barrier properties of film revealed that the lignin addition improved barrier properties against UV light in the range of 280-350 nm. Furthermore, the lowest scavenging activity was observed in LG-E (111.10 µg/ ml) trailed by LG-D (249.29 µg/ml) and LG-C (259.53 µg/ml). Conclusions:The LG films showed improved light barrier and antioxidant properties with low cytotoxicity, displaying great potential in food packaging and coating for preventing ultraviolet induced lipid oxidation with an extended biomedical applications.

Carboxymethyl cellulose-based films: Effect of organosolv lignin incorporation on physicochemical and antioxidant properties

“…Similar results were observed for starch/lignin films (Bhat et al, 2013), gelatin-lignosulfonate films (Núñez-Flores et al, 2012), gelatin/lignin films (Aadil et al, 2016a) and alginate/lignin films (Aadil et al, 2016b), being the film solubility approximately 33%, 41%, 65% and 45% lower, respectively, than the control films. On the other hand, Shankar et al (2015) obtained agar/lignin films with higher solubility than agar film (control).…”

“…Similar results were observed by Spiridon et al (2011) in starch/lignin films and according to them, can be assigned to the inter-component H-bonding, which may, in turn, improve the thermal stability of the films. Aadil et al (2016a) also reported enhanced thermal stability of the lignin/gelatin films. On the other hand, the thermal stability of alginate films decreased with the incorporation of lignin (Aadil et al, 2016b).…”

“…The antioxidant capacity can be attributed to some lignin groups presents in the surface with recognized antioxidant activity or to the migration of some of these free active molecules into the solution, such as monomers and oligomers, as well as other free phenols that could be present in the lignin samples, since lignins, as high molecular weight polymers, present low mobility (Crouvisier-Urion et al, 2016). Aadil et al (2016a) found that the free radical scavenging capacity of the gelatin/lignin films increased with the increase in lignin content, achieving 67.51% RSA (IC 50 111.10 μg/mL) in the water soluble fraction of film containing 40% lignin (the highest concentration). Nunez-Flores et al (2012 measured the antioxidant activity of the lignosulphonates and soda lignin used in the production of lignin/gelatin films and reported IC 50 of 83.4-97.5 μg/mL and 36.5 μg/mL, respectively.…”

“…Several works have incorporated water soluble lignin, such as lignosulphonates and alkali lignins in different biopolymers (Aadil et al, 2016a;Aadil et al, 2016b;Núñez-Flores et al, 2012Bhat et al, 2013;Miranda et al, 2015;Shankar et al, 2015;Crouvisier-Urion et al, 2016. Aadil and co-authors (2016a,b) reported that alkali lignin reduced the water affinity of alginate and gelatin films, respectively.…”

Lignin as the Basis for Obtaining Bioplastics

“…Різні види лігніну мають здатність поглинати УФ-випромінення. Ця властивість, разом із властивістю зменшувати набухання і водопроникність матеріалів, створює підґрунтя для отримання нових пакувальних матеріалів, які не були б чутливими до умов навколишнього середовища [22,23]. [9] Лужний [9] Oganocell [9] Alcell [9] Методи розділення Лігнін характеризується термопластичністю, і ця властивість може бути покращена завдяки селективній етерифікації фенольних гідроксильних груп лігніну [24].…”