Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7025, SE-750 07 Uppsala, Sweden.
Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7025, SE-750 07 Uppsala, Sweden.
Carbohydr Polym. 2017 Sep 15;172:365-373. doi: 10.1016/j.carbpol.2017.05.053. Epub 2017 May 24.
Wheat starch carbamates of different degrees of substitution were produced in laboratory experiments and for the first time their film forming performance were investigated. The carbamation reaction between urea and starch was investigated using a factorial design. Long reaction time, 2h, and high urea content, 10 and 25%, resulted in a high degree of substitution, 0.07 and 0.15, respectively. These starch carbamates were assumed to be cross-linked and showed best film forming properties resulting in continuous and firm films. Furthermore, a high degree of carbamate substitution favored a decrease in glass transition temperature (T) in cast films. The addition of acid as a catalyst for carbamation of starch produced inconsistent results and mainly lead to degradation of starch molecules that caused brittle films. FTIR and C NMR analyses confirmed the covalent bonding between urea and starch in starch carbamates. In a final step, production of starch carbamates was successfully scaled up. A potential industrial use of these starches is as oxygen barrier in multilayer food packaging.
在实验室实验中制备了不同取代度的小麦淀粉氨基甲酸酯，并首次研究了它们的成膜性能。采用析因设计研究了尿素和淀粉之间的氨基甲酸酯化反应。较长的反应时间（2 小时）和较高的尿素含量（10%和 25%）分别导致了较高的取代度（0.07 和 0.15）。这些淀粉氨基甲酸酯被认为是交联的，具有最佳的成膜性能，形成连续而坚固的薄膜。此外，较高的氨基甲酸酯取代度有利于降低铸膜的玻璃化转变温度（T）。添加酸作为淀粉氨基甲酸酯化的催化剂产生了不一致的结果，主要导致淀粉分子降解，从而导致薄膜易碎。FTIR 和 C NMR 分析证实了淀粉氨基甲酸酯中尿素和淀粉之间的共价键。最后，成功地扩大了淀粉氨基甲酸酯的生产规模。这些淀粉在多层食品包装中的潜在工业用途是作为氧气阻隔层。
