RESUMEN
The purpose of this work was to evaluate the effect of five novel synthetic antioxidants: octyl sinapate (OSA), octyl ferulate (OFA), octyl caffeate (OCA), cetyl sinapate (CSA) and cetyl ferulate (CFA) added to refined rapeseed oil for the first time on antioxidant activity (AA) and total phenolic content (TPC) in French fries. French fries after frying in enriched oils had higher the AA determined by three assays: 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS = 2907-20,029 µmol TE/100 g), 2,2-diphenyl-1-picrylhydrazyl (DPPH = 657-6886 µmol TE/100 g), ferric reducing antioxidant power (FRAP = 332-2659 µmol TE/100 g) and total phenolic content (TPC = 44-378 mg SA/100 g) than those prepared in refined rapeseed oil (ABTS = 2146 µmol TE/100 g, DPPH = 403 µmol TE/100 g, FRAP = 218 µmol TE/100 g, TPC = 14 mg SA/100 g). Moreover, the presence of phenolipids in rapeseed oil decreased the oil content in fried French fries by 22-45%. However, the AA and TPC in the fortified oils significantly increased, whereas slower changes in oxidation parameters of supplemented oils after frying were observed. A new lipophilic antioxidants can be useful for the development of management system for the preparation of French fries and the prolongation of frying oil shelf life.
RESUMEN
BACKGROUND: Lipophilisation allows the formation of new functionalised antioxidants having beneficial properties compared to natural hydrophilic phenolic acids. Therefore, this work focused on the synthesis of lipophilic antioxidants, such as a new octyl sinapate, octyl caffeate and octyl ferulate using the modified Fischer esterification of selected hydroxycinnamic acids with 1-octanol. RESULTS: The lipophilic octyl sinapate was obtained for the first time with satisfactory yield (83%) after purification by column chromatography. The identity of the synthesised phenolipids was confirmed by chromatographic and spectroscopic analyses. Antioxidant capacity of phenolipids was determined by DPPH (IC50 = 35.87-52.24 µg mL-1 ) and ABTS (IC50 = 39.45-48.72 µg mL-1 ) methods and compared with IC50 values (7.37-35.30 µg mL-1 and 7.55-41.67 µg mL-1 , respectively) for well known antioxidants. The antioxidant capacity of rapeseed-linseed oil enriched with the purified esters was about two to 30 times higher in comparison with a non-supplemented oil. CONCLUSION: The novel octyl sinapate as well as octyl caffeate and octyl ferulate have antioxidant properties and lipophilic character, therefore they may be added to vegetable oils as potential antioxidants for tackling oxidative processes. © 2017 Society of Chemical Industry.
