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Application of EPR Spectroscopy and DSC for Oxidative Stability Studies of Nigella sativa and Lepidium sativum Seed Oil
Author(s) -
Naik Azza,
Meda V.,
Lele S. S.
Publication year - 2014
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-014-2430-5
Subject(s) - lepidium sativum , nigella sativa , dpph , chemistry , differential scanning calorimetry , antioxidant , food science , polyunsaturated fatty acid , organic chemistry , botany , fatty acid , biology , traditional medicine , medicine , germination , thermodynamics , physics
Food products incorporating oil rich in polyunsaturated fatty acids are known to become easily rancid. In order to delay the process of oxidation there is a need to develop analytical methods that accurately estimate the antioxidant potential of the oil and predict its oxidative stability. Thus, the present work investigated Lepidium sativum and Nigella sativa seed oil as a source of natural antioxidants. Further, the effect of blending the two oils on the oxidative stability of the unsaturated L. sativum oil was also studied. Electro‐paramagnetic resonance (EPR) spectroscopy showed 100 % 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical quenching by both the oils at a concentration of 5 % w/v oil in benzene thereby establishing the anti‐oxidant potential of both the oils. Differential scanning calorimetry (DSC) studies showed addition of N. sativa oil to L. sativum oil enhanced its oxidation onset temperature, a relevant indicator of oil stability, thereby making N. sativa a source of natural antioxidants. Consequently, the DSC and EPR spectroscopy techniques so developed can find application in shelf life studies of oil.