Petronilho Sílvia, Oliveira André, Domingues M Rosário, Nunes Fernando M, Coimbra Manuel A, Gonçalves Idalina
LAQV-REQUIMTE, Department of Chemistry, Campus Universitário de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal.
Chemistry Research Centre-Vila Real, Department of Chemistry, University of Trás os-Montes and Alto Douro, Quinta de Prados, 5001-801 Vila Real, Portugal.
Foods. 2021 Nov 23;10(12):2897. doi: 10.3390/foods10122897.
Starch is a promising candidate for preparing biodegradable films with useful gas barriers and thermoplastic capabilities. However, these materials are hydrophilic and brittle, thus limiting their application range. To overcome these drawbacks, it has been hypothesized that starch can be hydrophobized and plasticized during the starch-based film production using a single-step approach and following transesterification principles. In this work, KOH powder and spent frying oil (SFO) were used as an alkaline catalyst and a source for triacylglycerides, respectively, to promote the modification of starch. Different ratios of SFO (/ related to the dried starch weight) were tested. When compared to the neat films (without a catalyst and SFO), the incorporation of at least 15% SFO/KOH gave rise to transparent, hydrophobic (water contact angles of 90∘), stretchable (. 20×), elastic (. 5×), and water tolerant starch-based films, contrary to the films produced without the catalyst. ATR-FTIR and H NMR revealed structural differences among the produced films, suggesting that starch was modified with the SFO-derived fatty acids. Therefore, adding KOH during the potato starch/spent frying oil-based film's production was determined to be a promising in situ strategy to develop starch-based materials with improved hydrophobicity and flexibility, while valorizing the potato chip industry's byproducts.
淀粉是制备具有有用气体阻隔性和热塑性能力的可生物降解薄膜的有前途的候选材料。然而，这些材料具有亲水性且易碎，因此限制了它们的应用范围。为了克服这些缺点，有人提出可以在基于淀粉的薄膜生产过程中采用单步方法并遵循酯交换原理对淀粉进行疏水化和增塑处理。在这项工作中，分别使用氢氧化钾粉末和煎炸废油（SFO）作为碱性催化剂和三酰甘油的来源，以促进淀粉的改性。测试了不同比例的SFO（相对于干燥淀粉重量）。与纯薄膜（无催化剂和SFO）相比，加入至少15%的SFO/KOH可得到透明、疏水（水接触角为90°）、可拉伸（伸长率>20倍）、有弹性（伸长率>5倍）且耐水的淀粉基薄膜，这与未添加催化剂制备的薄膜不同。衰减全反射傅里叶变换红外光谱（ATR-FTIR）和核磁共振氢谱（1H NMR）揭示了所制备薄膜之间的结构差异，表明淀粉已被SFO衍生的脂肪酸改性。因此，在基于马铃薯淀粉/煎炸废油的薄膜生产过程中添加氢氧化钾被确定为一种有前途的原位策略，可用于开发疏水性和柔韧性得到改善的淀粉基材料，同时实现薯片行业副产品的增值利用。
