Modified Gelatin Films from Croaker Skins: Effects of pH, and Addition of Glycerol and Chitosan

Abstract

This work evaluated the effects of pH (3, 4 and 5) and addition of glycerol (10, 20 and 30%, w/w) in films of gelatin extracted from croaker skins, and afterward modified by chitosan. The gelatin films were produced by casting technique. The chitosan additions (10, 20 and 30% w/w) in relation to the gelatin films were analyzed. Films were characterized as tensile strength (TS), elongation, water vapor permeability (WVP) and optical properties (color, color variation and opacity). Gelatins were characterized for gel strength (221 g) and viscosity (3.7 cP), and chitosan was obtained from shells of shrimp and characterized (150 kDa and deacetylation degree of 85%). The gelatin film with 10% (w/w) glycerol and pH 4 showed the best TS value and suitable WVP value. The amount of chitosan of 10% (w/w) added to the gelatin film on the best conditions produced the modified films with the best properties of TS and WVP. PRACTICAL APPLICATIONSSeveral types of biopolymeric films have been developed, combining proteins and polysaccharides, and among these, gelatin and chitosan take on homogeneous form because of miscibility between the two biopolymers. Improvements in the connection crossed in gelatin mixture with chitosan are attributed to the formation of polielectrolic compounds, among the groups of amino of the chitosan and of the groups of lateral chains charged negatively of the gelatin through electrostatic interaction. The study of the mechanical properties of the biodegradable films is a subject of great importance, because of its influence on the acting of the product and the consumer's acceptance. In this context, the intensification need is observed in the studies about the gelatin extraction starting from fish skins and its application in the production of pure and modified films with chitosan and plasticizer.

Preparation and Characterization of Chitosan Nanoparticles‐Loaded Fish Gelatin‐Based Edible Films

“…; Bandeira et al . ). However, like the other biopolymer films, gelatin‐based films are very sensitive to moisture and susceptible to lose their dimensional stability easily at room temperature (Hosseini et al .…”

“…Gelatin, a natural polymer, has a good potential to form edible films due to its abundance and biodegradability, as well as excellent barrier properties against oxygen and flavor (Bigi et al 2002;Bandeira et al 2015). However, like the other biopolymer films, gelatin-based films are very sensitive to moisture and susceptible to lose their dimensional stability easily at room temperature (Hosseini et al 2013).…”

Whey protein isolate with improved film properties through cross‐linking catalyzed by small laccase from Streptomyces coelicolor

“…In recent decades, edible films and coatings derived from biodegradable biopolymers have aroused great interest from scientific researchers for fresh food applications, because synthetic plastics are of social and environmental concern . These biopolymers mainly include polysaccharides, proteins as well as combinations of these components .…”

Antimicrobial Evaluation of Gelatin–based Films Incorporated With Chitosan in the Conservation of Fish Fillets / Avaliação Antimicrobiana De Filmes À Base De Gelatina Incorporados Com Quitosano Na Conservação De Filtes De Peixe

“…Gelatin-based films were made according to Bandeira, et al, (2015). The fish gelatin solution, containing 1.8 g (w/v) of gelatin, was stirred for 30 min on a magnetic stirrer (FISATOM 752A, Brazil) at 300 rpm and a temperature of 30 ± 2ºC.…”

“…Chitosan is a cationic polysaccharide, obtained from the deacetylation of chitin (Moura, et al, 2015). It has unique biological characteristics, such as biodegradability, biocompatibility, non-toxicity, and antimicrobial and antibacterial properties (Priyadarshi and Rhim, 2020).…”