Tian Yixing, Acevedo Nuria C
Department of Food Science and Human Nutrition, Iowa State University 2543 Food Science Building Ames IA 50011 USA
RSC Adv. 2020 Jan 14;10(5):2526-2535. doi: 10.1039/c9ra07820g.
Exposure of retinyl palmitate (RP) to ultraviolet radiation can lead to its photo-degradation and loss of biological activity. Therefore, there is a demand to explore new approaches to protect RP in an easy, economical and efficient way. The objective of this study was to explore the role of policosanol oleogels (PCOs) in the protection of RP from photodegradation. UV-blocking action was tested by placing a layer of PCO as a barrier between a UVA (365 nm) source and 1% RP in soybean oil. Effects of structural characteristics of PCOs cooled at different rates on RP photostability were also studied. The ability of PCOs to prevent radical-mediated reactions was assessed by measuring oil oxidative stability over storage time at 40 °C. The remaining % RP was measured by HPLC during 4 days of UVA irradiation. PCO blocked energy absorption from UVA and further dampened the UVA mediated ionic photodissociation and free radical reactions due to matrix immobilization. After 4 days of UV exposure, photodegradation of RP was reduced by 64% when a PCO layer was used as a barrier. Peroxide values (PV) and -anisidine values (-A.V.) of soybean oil (SO) were significantly higher than those of PCOs over storage time. Cooling rate processing played a significant role in RP protection; the faster the cooling rate, the higher the RP photostability. This study demonstrated that the protective mechanism of RP in PCOs is a combined effect of physical UV-barrier action, molecular immobilization and inhibition of the free radical-mediated reaction.
视黄醇棕榈酸酯（RP）暴露于紫外线辐射会导致其光降解并丧失生物活性。因此，需要探索简便、经济且高效的方法来保护RP。本研究的目的是探究聚二十碳烯醇油凝胶（PCOs）在保护RP免受光降解方面的作用。通过在UVA（365 nm）光源与大豆油中的1% RP之间放置一层PCO作为屏障来测试其紫外线阻挡作用。还研究了以不同速率冷却的PCOs的结构特征对RP光稳定性的影响。通过在40°C下储存期间测量油的氧化稳定性来评估PCOs预防自由基介导反应的能力。在UVA照射4天期间，通过高效液相色谱法测量剩余的RP百分比。PCO阻挡了UVA的能量吸收，并由于基质固定作用进一步抑制了UVA介导的离子光解离和自由基反应。在紫外线暴露4天后，当使用PCO层作为屏障时，RP的光降解减少了64%。在储存期间，大豆油（SO）的过氧化值（PV）和对茴香胺值（-A.V.）显著高于PCOs。冷却速率处理在保护RP方面发挥了重要作用；冷却速率越快，RP的光稳定性越高。本研究表明，PCOs中RP的保护机制是物理紫外线阻挡作用、分子固定作用以及对自由基介导反应的抑制作用的综合效果。
