酸溶剂对葛根淀粉/壳聚糖复合可食膜性能的影响

为了考察壳聚糖酸溶剂对葛根淀粉/壳聚糖复合可食膜抗菌、物理和机械性能的影响,该文选择质量分数为1%的乙酸、乳酸、苹果酸为溶剂,配制质量体积比2g/L的葛根淀粉-壳聚糖复合膜液,以0.5g/L的抗坏血酸为活性添加剂,0.6g/L的丙三醇为增塑剂,0.1g/L的吐温20为表面活性剂,采用流延法制备可食性复合膜。结果表明:复合膜液具有一定的表面活性;酸溶剂未对膜液表面张力产生显著影响。有机酸溶剂种类对复合膜性能影响显著,其中乙酸复合膜的机械强度最大,平均抗拉强度和穿透力分别为5.73MPa和8.63N,水溶性最小,约34%,对抗坏血酸缓释效果最明显;乳酸复合膜的延展性最优,平均断裂伸长率和穿透距离分别为71.5%和6.05mm;苹果酸复合膜的抑菌效果最佳,对大肠杆菌和金黄色葡萄球菌的抑制率分别达到98.9%和81.2%,阻水性最强,透湿系数为4.824.82×10-11g/(m·s·Pa),故可根据不同使用目的选择相应复合膜。研究结果为该类复合包装膜在实际食品上的应用提供理论依据。

Effects of acid solvents on properties of kudzu starch/chitosan composite edible films

In order to evaluate the effects of acid solvents on antibacterial, physical and mechanical properties of composite edible films, the kudzu starch-chitosan composite film-forming solutions were prepared by tape casting with mass fraction 1% of acetic acid, lactic acid and malic acid as solvents. For the film, 0.5g/L of ascorbic acid as the active additive, 0.6g/L of glycerol as the plasticizer and 0.1g/L of Tween 20 as the surfactant were added into the solutions. It was found that there was certain surface activity for film-forming solution, and acid solvent had no obvious impact on the surface tension of each solution. The types of acid solvents had obvious impact on the performance of composite films, in which the film with acetic-acid solvent had best mechanic strength, the mean tensile strength and puncture strength were 5.73 MPa and 8.63 N, respectively, and its solubility was the smallest, which was about 34%. The film made from lactic acid solution displayed the greatest flexible property, which mean elongation and puncture distance were 71.5% and 6.05 mm, respectively. The composite film using malic acid as solvent showed the best antibacterial activity against escherichia coli and staphylococcus aureus, which were 98.9% and 81.2%, respectively, and its water-tightness was best, which the water vapor permibility was 4.82×10-11 g/(m·s·Pa). So different acid solvents can be selected to prepare films according to different requirements. The study results can provide theoretical references for the application of edible films.