Department of Food Science, Rutgers University , 65 Dudley Road, New Brunswick, New Jersey 08901, United States.
J Agric Food Chem. 2013 Aug 7;61(31):7462-9. doi: 10.1021/jf4017527. Epub 2013 Jul 29.
The effects of different concentrations of ubiquinol-10 (Q10H2) on citral's stability were systematically investigated and compared in citral-loaded oil-in-water (O/W) nanoemulsions. Solid phase microextraction gas chromatography (SPME-GC) was employed to monitor the degradation of citral and the formation of off-flavor compounds throughout storage at 25 and 45 °C. The optimum concentration of Q10H2 in the current formulation was determined to be around 0.10 wt % in the system (Q10H2/citral ratio 1:1), which can effectively protect citral from chemical degradation and oxidation. Results suggested, however, that a low concentration of Q10H2 may induce the majority of the ubisemiquinone (Q10(•-))/ubiquinone (Q10) redox transition, which possibly endowed Q10H2 with pro-oxidant properties. Further increase in Q10H2 concentration beyond a certain value also hindered its effect due to the complex properties of radicals involved and the overall environment encountered. With appropriate concentrations of Q10H2 presented in the system, major citral oxidation off-flavor compounds (p-cresol, α,p-dimethylstyrene, p-methylacetophenone), and some of the lipid degradation products can be inhibited to lower levels. In contrast, ubiquinone-10 (Q10) had a negligible effect on citral's chemical stability and off-flavor generation.
系统研究并比较了不同浓度的泛醇-10（Q10H2）对柠檬醛负载的油包水（O/W）纳米乳液中柠檬醛稳定性的影响。采用固相微萃取气相色谱（SPME-GC）监测柠檬醛在 25 和 45°C 储存过程中的降解和异味化合物的形成。确定当前配方中 Q10H2 的最佳浓度约为 0.10wt%（Q10H2/柠檬醛比例为 1:1），可有效保护柠檬醛免受化学降解和氧化。然而，结果表明，低浓度的 Q10H2 可能会诱导大多数半泛醌（Q10(•-)/泛醌（Q10）氧化还原转换，这可能使 Q10H2 具有促氧化剂特性。进一步增加 Q10H2 浓度超过一定值也会由于涉及的自由基的复杂性质和整体环境而阻碍其效果。在系统中呈现适当浓度的 Q10H2 时，可以抑制主要的柠檬醛氧化异味化合物（对甲酚、α，p-二甲基苯乙烯、对甲基苯乙酮）和一些脂质降解产物的形成，使其含量降低。相比之下，泛醌-10（Q10）对柠檬醛的化学稳定性和异味生成几乎没有影响。
