Effects of plasticizers on the properties of edible films from skin gelatin of bigeye snapper and brownstripe red snapper

The effects of type and concentration of plasticizers on the mechanical properties (tensile strength, TS and elongation at break, EAB), water vapor permeability, light transmission, transparency and color of fish skin gelatin edible films from bigeye snapper (Priacanthus marcracanthus) and brownstripe red snapper (Lutjanus vitta) were investigated. At the same plasticizer concentration, fish skin gelatin films from both species plasticized with glycerol (Gly) showed the greatest EAB (P < 0.05), whereas ethylene glycol (EG) plasticized films showed the highest TS (P < 0.05). Films prepared from brownstripe red snapper skin gelatin exhibited slightly greater TS than those of bigeye snapper skin gelatin (P < 0.05) when Gly and sorbitol (Sor) were used. EG, polyethylene glycol 200 (PEG 200) and polyethylene glycol 400 (PEG 400) affected the mechanical properties of both films differently. Films generally became more transparent and EAB, water vapor permeability (WVP), as well as light transmission of films increased, but TS and yellowness decreased with increasing plasticizer concentrations.