The Effect of Cross-Linking with Citric Acid on the Properties of Agar/Fish Gelatin Films

Abstract

The aim of this work was to assess the effect of fish gelatin–citric acid nucleophilic substitution and agar–citric acid esterification reactions on the properties of agar/fish gelatin films. Since temperature is an important cross-linking parameter, films were treated at 90 °C and 105 °C and film properties were compared to those of non-cured films. It was observed that temperature favored the aforementioned reactions, which induced physical and morphological changes. In this regard, darker films with a rougher surface were obtained for the films with a higher cross-linking degree. While mechanical properties were slightly modified, the barrier properties were enhanced due to the reactions that occurred. Therefore, these agar/fish gelatin films cross-linked through two different reactions can be considered to be promising materials as active films for different purposes, such as active packaging or pharmaceutical applications.

Preparation and Characterization of a New Polymeric Multi-Layered Material Based K-Carrageenan and Alginate for Efficient Bio-Sorption of Methylene Blue Dye

“…A peak centered at 1705 cm –1 appeared referring to the ester groups confirming the polyesterification reaction established between carboxylic groups of citric acid and hydroxyl functions of both alginate and carrageenan biopolymers. This is in line with previous research studies, in which FT-IR were used to confirm the evidence of a polyesterification reaction between cellulosic material and different polysaccharides via polycarboxylic acids as crosslinking agents [ 32 , 33 , 34 ]. A peak closed to 1310 cm –1 appeared clearly, which corresponded to the symmetric stretching vibration of the carboxylic acid groups COO _ of galacturonic acid of alginate grafted polymer [ 35 ].…”

Impact of Drying Regimes and Different Coating Layers on Carboxymethyl Cellulose Cross-Linked with Citric Acid on Cotton Thread Fibers for Wound Dressing Modification

“…After the threads were soaked, the threads were pulled out from the syringe and were immediately submerged into beakers containing heated 2M, 3M, and 4M CA. The threads were left immersed for 1 h at 90 °C with constant stirring to promote CA and CMC interaction [ 23 , 24 ]. After the immersion, the excess CA was removed using filtered paper, and the thread groups were separately dried using OD and IR drying techniques at 65 °C for 30 min.…”

Catalyst-Free Crosslinking Modification of Nata-de-Coco-Based Bacterial Cellulose Nanofibres Using Citric Acid for Biomedical Applications

“…Citric acid (CA) is one of the organic acids classified as "generally regarded as safe" (GRAS) by the US food and drug administration (FDA) that has long been used as a modifier on many polymeric biomaterials via crosslinking, including BC [16][17][18][19][20]. Modifying polymeric biomaterials with CA typically yields what is known as citrate-based biomaterials (CBBs) [21,22].…”