|
|||||
|
|
Antioxidant potential of rice bran extracts and its effects on stabilisation of cookies under ambient storage |
|
| Authors: | Muhammad Iqbal Bhanger Shahid Iqbal Farooq Anwar Muhammad Imran Mubeena Akhtar & Muhammad Zia-ul-Haq |
| Affiliation: | National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080, Pakistan; Department of Chemistry, University of Sargodha, Sargodha 40100, Pakistan; Department of Chemistry, University of Agriculture, Faisalabad 38040, Pakistan; Department of Chemistry, Bahauddin Zakariya University, Multan 60800, Pakistan |
| Abstract: | Methanolic extracts of rice bran (MRB) were found to be the richest in phenolics than all the other extraction media, i.e. water, 80% methanol, 70% ethanol, diethyl ether. Thermal stability of MRB was determined by evaluating antioxidant activity of heated extracts in linoleic acid system. Cookies were prepared in sunflower oil premixed with MRB at different concentrations, i.e. 500, 1000 and 2000 ppm, and with butylated hydroxytoluene and α‐tocopherol at 200 ppm. Oxidative stability of cookies was measured by storing under ambient conditions for an year with periodical analysis after every 2 months. Fatty acid composition was determined by gas–liquid chromatography. A regular decrease in unsaturated fatty acids (USFA) and increase in saturated fatty acids was observed with the increase in storage period; all the stabilised samples showed appreciably less decrease in USFA than that of control sample. Induction period ranged from 14.73 to 31.22 h while control exhibited 7.5 h. Peroxide value, iodine value and free fatty acids were chosen as the parameters for quality evaluation of cookies. Results suggest rice bran to be a potential source of antioxidants for stabilisation of cookies. |
| Keywords: | Ambient storage antioxidant activity cookies fatty acid composition induction period oxidative stability rice bran thermal stability |