棕榈蜡-壳聚糖膜的表征及对葡萄的保鲜应用

Characterization of carnauba wax-chitosan film and its application on grape preservation

为探讨巴西棕榈蜡对壳聚糖膜物理与功能特性的影响,向含有1 g/100 mL壳聚糖的醋酸溶液中加入巴西棕榈蜡以配制成不同质量浓度(0.1,0.2,0.3,0.4,0.5 g/100 mL)的复合膜溶液,进一步制备成相应的复合膜.同时,以不添加巴西棕榈蜡的壳聚糖膜液制备而成的膜作为空白对照.结果表明:与对照组相比,随着巴西棕榈蜡含量的增加,复合膜的力学性能、光学阻隔性能、疏水性能和热稳定性均得到显著改善,这可能与巴西棕榈蜡的疏水性及其与壳聚糖分子间的氢键和静电相互作用有关.当巴西棕榈蜡添加量为0.3 g/100 mL时,复合膜具有良好的物理性能,其拉伸强度为10.64 MPa,断裂伸长率为83.80%,接触角为68°.此外,巴西棕榈蜡-壳聚糖复合膜的涂膜可降低贮藏期间‘巨峰’葡萄果实的腐烂率和失重率,较好地维持其贮藏品质,延长其贮藏寿命.由此,巴西棕榈蜡的加入有利于提高壳聚糖膜作为可食用膜的适用性.

To investigate the effect of carnauba wax on the physical and functional properties of chitosan film,carnauba wax was added to the acetic acid solution containing 1 g/100 mL chitosan to prepare the composite film solutions with different concentrations(0.1,0.2,0.3,0.4,0.5 g/100 mL).Meanwhile,the film prepared from chitosan film solution without carnauba wax was used as the control group.The results showed that compared with the control group,the mechanical properties,optical barrier properties,hydrophobic properties and thermal stability of the composite films were significantly improved with the increase of carnauba wax content,which may be associated with the hydrophobicity of carnauba wax and its hydrogen bond and electrostatic interaction with chitosan molecules.When the content of carnauba wax was 0.3 g/100 mL,the composite film had good physical properties,with tensile strength of 10.64 MPa,elongation at break of 83.80%,and contact angle of 68°.In addition,carnauba wax-chitosan composite coating could decrease the decay and weight loss rate of‘Jufeng’grapes,thereby maintaining its postharvest quality and prolonging its shelf life.Therefore,the addition of carnauba wax is conducive to improve the applicability of chitosan film as edible film.