The aim of this study was to assess and improve the oxidative stability of red raspberry seed oil–RO, a potential topical ingredient derived from food industry by-products, on its own and when incorporated in low energy nanoemulsion (NE). The RO’s oxidative stability was assessed at 5, 25, and 40 °C during one month of storage and expressed in: peroxide value, p-anisidine, and thiobarbituric reactive substances—TBARS value, while for NEs, lipid hydroperoxides and TBARS values were monitored. Both synthetic (butylated hydroxytoluene—BHT and ethylenediaminetetraacetic acid—EDTA), and natural (oregano essential oil—ORE and oak fruit extract—OAK) antioxidants were used. Pure RO and RO with BHT or ORE were stable at 5 °C and 25 °C, but at 40 °C BHT showed only moderate protection, while ORE was prooxidant. NEs prepared with new biodegradable polyglycerol esters-based surfactants, with droplet sizes of < 50 nm and narrow size distribution, showed improved physicochemical stability at room temperature, and especially at 40 °C, compared to NEs with polysorbate 80, which required the addition of antioxidants to preserve their stability. Natural antioxidants ORE and OAK were compatible with all NEs; therefore, their use is proposed as an effective alternative to synthetic antioxidants.

中文翻译：

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红树莓籽油低能纳米乳液：表面活性剂、抗氧化剂和温度对氧化稳定性的影响

本研究的目的是评估和改善红树莓籽油 – RO 的氧化稳定性，RO 是一种潜在的外用成分，来自食品工业副产品，单独使用以及掺入低能纳米乳液 (NE) 时。RO 的氧化稳定性在 5、25 和 40 °C 下一个月的储存期间进行评估，并表示为：过氧化值、对茴香胺和硫代巴比妥酸反应物质-TBARS 值，而对于 NE，监测脂质氢过氧化物和 TBARS 值. 使用了合成（丁基化羟基甲苯—BHT 和乙二胺四乙酸—EDTA）和天然（牛至精油—ORE 和橡树果实提取物—OAK）抗氧化剂。纯 RO 和含有 BHT 或 ORE 的 RO 在 5 °C 和 25 °C 下稳定，但在 40 °C 时 BHT 仅显示中等保护，而 ORE 是促氧化剂。与使用聚山梨醇酯 80 的 NE 相比，使用新型可生物降解聚甘油酯基表面活性剂制备的 NE，液滴尺寸 < 50 nm 且尺寸分布窄，在室温下表现出更高的物理化学稳定性，尤其是在 40 °C 时，需要添加抗氧化剂以保持其稳定性。天然抗氧化剂 ORE 和 OAK 与所有 NE 相容；因此，建议将它们用作合成抗氧化剂的有效替代品。