The Influence of Cysteine on the Performances of Gelatin Film

Abstract

In order to explore the cysteine as a potential plasticizer for gelatin films, the influences of the amount of cysteine, pH and reaction temperature on the functional performances including water absorption, mechanical performances, and chromaticity of gelatin films have been investigated. The results indicated that the amount of cysteine, pH and reaction temperature did not affect the water absorption and chromaticity of the gelatin film. However, the mechanical performances of the gelatin film were influenced greatly by the amount of cysteine and water bath temperature. With the concentration of cysteine ranging from 0 to 0.02%, the tensile strength (TS) of the gelatin film had no significant change but the elongation at break (EB) increased gradually. When the concentration of cysteine ranged from 0.01% to 0.02%, the largest value of the EB of gelatin film was obtained. When the concentration of cysteine was greater than or equal to 0.04%, the TS and EB of the gelatin film decreased significantly. When the reaction temperature was 60 ∼ 90°C, the largest values of the EB and TS of the gelatin film were obtained. The addition of cysteine as a plasticizer can improve the EB of gelatin film, but has no influence on other performances. Therefore, there is a promising application value for cysteine in food preservation packaging film, due to its advantages of biodegradability and wide source.