کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
70707 | 48842 | 2009 | 5 صفحه PDF | دانلود رایگان |
The synthesis of palm-based ascorbyl esters through transesterification of ascorbic acid and palm oil in tert-amyl alcohol catalyzed by immobilized lipase is described. Highest conversion (70–75%) was determined after 16 h reaction at 40 °C using lipase (Novozyme 435 from Candida antartica) with an ascorbic acid to palm oil mole ratio of 1:8. The purified product was further characterized by 13C NMR and GC–MS and the mixture of ascorbyl monoesters obtained were identified as ascorbyl monooleate (61%), ascorbyl monopalmitate (30%) and ascorbyl monostearate (9%). The antioxidant activity of palm-based ascorbyl esters was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) test. The results showed that pure palm-based ascorbyl esters have an antioxidant activity with an IC50 value of 0.1 mg/mL.
Journal: Journal of Molecular Catalysis B: Enzymatic - Volume 58, Issues 1–4, June 2009, Pages 153–157