Influence of the hydrophilic head size and hydrophobic tail length of surfactants on the ability of micelles to stabilize citral
Influence of the hydrophilic head size and hydrophobic tail length of surfactants on the ability of micelles to stabilize citral
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DOI：
10.1002/jsfa.7505
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发表时间：
2016-07-01
影响因子：
4.1
通讯作者：
Choi, Seung Jun
中科院分区：
文献类型：
--
作者：
Hong, Chi Rac;Park, Sung Joon;Choi, Seung Jun
背景：表面活性剂胶束可以控制难溶食品香精的化学降解速度。为了评价表面活性剂的分子结构对柠檬醛化学降解率的影响，用分子结构相似但亲水头部大小和疏水尾长不同的聚氧乙烯醚型表面活性剂制备了胶束。结果：在表面活性剂的临界胶束浓度为20倍时，无论亲水头部大小或疏水尾长如何，柠檬醛在胶束中的化学降解率在中性pH下都没有显著差异。在酸性环境中，柠檬醛的降解速率常数一般随表面活性剂亲水头部尺寸的增大而成比例增加(对于23和100个氧乙烯基团的表面活性剂，分别为0.1563和0.2217)，但疏水尾长对柠檬醛的稳定性没有影响。单胶束溶液和含铁胶束溶液柠檬醛的降解速率常数相差不大(含Fe~(3+)和不含Fe~(3+)分别为0.2217和0.2265)，表明无论Fe~(2+)和Fe~(3+)以何种形式存在，铁离子都不能加速柠檬醛在胶束中的降解。结论：尽管表面活性剂的浓度可能是相关的，但如果能将其浓度作为临界胶束浓度来控制，那么在酸性条件下，具有较小亲水头的聚乙烯烷基醚型表面活性剂能更有效地稳定柠檬醛。(C)2015年化学工业学会
BACKGROUND: Surfactant-made micelles can control the rate of chemical degradation of poorly water-soluble food flavors. To evaluate how the molecular structure of surfactant has an influence on the chemical decomposition rate of citral, micelles were prepared with polyoxyethylene alkyl ether-type surfactants that had similar molecular structures but various hydrophilic head sizes and hydrophobic tail lengths.RESULTS: At a critical 20x micelle concentration of surfactant, there was no significant difference in the chemical degradation rate of citral in micelles in neutralpH, regardlessof thehydrophilic head size orhydrophobic tail length. In an acidic environment, the degradation rate constant of citral generally increased proportionally with increasing hydrophilic head size of surfactant (0.1563 and 0.2217 for surfactants with 23 and 100 oxyethylene units, respectively) but the length of hydrophobic tail did not affect the citral stability. Also, little difference (0.2217 and 0.2265 for surfactant having 100 oxyethylene units with and without Fe3+) in degradation rate constant of citral between simple micellar solution and micellar solution containing iron suggested that iron ions could not accelerate citral degradation in micelles, regardless of the form of iron (Fe2+ and Fe3+).CONCLUSION: This work concludes that although the concentration of surfactant could be relevant, if its concentration could be controlled in the samemanner as the critical micelle concentration, then a polyethylene alkyl ether-type surfactantwith a small hydrophilic head couldmore efficiently stabilize citral at an acidic pH. (C) 2015 Society of Chemical Industry