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Antioxidant activity and lipid peroxidation in Artemia nauplii enriched with DHA‐rich oil emulsion and the effect of adding an external antioxidant based on hydroxytyrosol 
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下载免费PDF全文 Elena Viciano Óscar Monroig Carlos Barata Carlos Peña Juan Carlos Navarro 《Aquaculture Research》2017,48(3):1006-1019
Artemia nauplii catabolize polyunsaturated fatty acids (PUFA); in particular, they retroconvert docosahexaenoic acid (DHA, 22:6n‐3), so enrichment is a continuous quest towards increasing PUFA through the use of PUFA‐rich enrichment products. However, optimal conditions during enrichment (aeration, illumination and temperatures around 28°C) tend to accelerate autoxidation of PUFA and the formation of potentially toxic oxidation products. Water‐soluble antioxidants like the polyphenolic compound hydroxytyrosol (3,4‐dihydroxyphenylethanol), a polar molecule found in the water fraction resulting after the milling process of olives, arise as promising compounds to prevent oxidation during Artemia enrichments. We investigated the antioxidant activity and lipid peroxidation in Artemia nauplii during enrichment and the effect of adding an external antioxidant based on hydroxytyrosol during the enrichment with a PUFA‐rich emulsion (M70). For this purpose, the activity of antioxidant enzymes (catalase, superoxide dismutase, glutathione‐S‐transferase, glutathione peroxidase), as well as lipid peroxidation, was determined in enriched and unenriched Artemia nauplii. To validate antioxidant activity and lipid peroxidation, in a first experiment, nauplii were enriched with microalgae (Tetraselmis suecica), yeast (Saccharomyces cerevisiae) and M70 emulsion. In a second experiment, enrichment with a commercial emulsion (DC Super Selco), M70, and a combination of M70 and hydroxytyrosol (Hytolive, HYT) added as an external antioxidant were performed. The combination of M70 with HYT produced the best results, in terms of activity of antioxidant enzymes. The analysis of the fatty acids from total lipids showed that the addition of hydroxytyrosol preserved the DHA percentage of enriched nauplii. 相似文献
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研究不同升温速率(β=5、10、20、40 K/min)下羟基酪醇的热稳定性、分解动力学和贮存期。利用热重分析得到羟基酪醇在氮气氛围中不同升温速率(β)下的热分解曲线,运用3种多升温速率法Kissinger法、Friedman法和Flynn-Wall-Ozawa法以及2种单升温速率方法 Coats-Redfern法和Achar法进行动力学分析,计算热分解的表观活化能(Ea)和指前因子(A),且根据Ea和A推算羟基酪醇的贮存期。结果显示:羟基酪醇的热分解过程一步完成,在升温速率为10 K/min时,从260~409℃为羟基酪醇的主要失重阶段;TG曲线随着温度的升高而迅速出现陡峭明显的失重台阶,DTG曲线亦出现负值,且随着温度的升高而急剧下降,在305.2℃达到了DTG的峰值,此时达到最大热失重速率为-12.91%/min;升温速率的变化对羟基酪醇的分解有影响,随着速率的升高,羟基酪醇的热分解温度逐渐升高,热分解曲线略微向高温移动,呈现了分解滞后现象。羟基酪醇的热分解机制符合一维扩散(D1)模型。测得平均Ea为122.40 k J/mol,A为3.37×1010min-1。根据Ea和A可推断,在室温25℃下,羟基酪醇在氮气氛围下的理论贮存期为4~5年。 相似文献
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