月桂酸添加方式对甘薯淀粉及膜性能的影响

Effect of the Modes of Adding Lauric Acid on Properties of Sweet Potato Starch and Sweet-Potato-Starch-Based Films

采用甘油为增塑剂制备淀粉膜,研究了月桂酸添加方式对甘薯淀粉及膜性能的影响。结果表明:对淀粉进行方法Ⅰ(加热后添加月桂酸)处理时,直链淀粉-脂质复合物分布在淀粉颗粒表面和内部,而对淀粉进行方法Ⅱ(加热前添加月桂酸)处理时,直链淀粉-脂质复合物主要分布在淀粉颗粒表面;方法Ⅰ和方法Ⅱ处理后的淀粉在热分析图中均出现了直链淀粉-脂质复合物的熔融峰;随着月桂酸的加入,淀粉糊各特征点黏度值均出现不同程度的改变;加入月桂酸后,淀粉结晶度降低,在2θ=20.15°处均出现了直链淀粉-脂质复合物的特征衍射峰;加入月桂酸后,淀粉膜表面变得平整,断裂伸长率降低,而抗拉强度和接触角变大;与方法Ⅰ相比,方法Ⅱ更适宜制备淀粉膜。

Sweet potato starch （SPS） -based films were prepared with glycerol as a plasticizer. The effects of modes of adding lauric acid （LA） on the properties of SPS and SPS - based films were studied. The result showed that the amylose - lipid complex was distributed on the sufance of starch granules and inside when starch was treated by method Ⅰ （ adding lauric acids after heating）, while amylose - lipid complex prepared by method Ⅱ （ adding laurie acids before heating） was mainly distributed on the surface of starch granules. In the thermograms, the fusion peak of amylose - lipid complex appears. The addition of the LA changes the feature point viscosity values of SPS. The addition of LA causes a decrease in relative crystallinity, and emerges the feature diffraction peak at around 20 of 20.15°. With the addition of LA, the surface of the films become smooth and the elongation at break is decreased, while the tensile strength and contact angle were increased. Compared with method Ⅰ, method Ⅱ was more suitable for preparation of starch -based films.