Storage stability of bleached rice bran wax organogels and water-in-oil emulsions

In this study, the effects of storage time (90days) at refrigerated (4 +/- 2 degrees C) and room (30 +/- 2 degrees C) temperatures on the quality of bleached rice bran wax organogels (BRXO) and water-in-oil (W/O) emulsions prepared using organogels (EO) were determined. BRXO was produced by mixing rice bran oil (RO) with bleached rice bran wax (BRX, 9% wax). EO (20% aqueous phase, 80% oil phase) was prepared with BRXO without adding an emulsifier. All quality attributes changed during storage at both temperatures. The colors of BRXO and EO were slightly changed, while those of RO and the emulsion without the addition of organogels (E) were notably changed. EO showed better stability than E. In assessing the various stages of oxidative stability, the peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) were determined. The PV peaked at 30days (E and EO) and 90 days (RO and BRXO) and later declined. TBARS values decreased with a decrease in the storage temperature and time. There were no significant changes in the firmness, hardness or stickiness of BRXO and EO at 30 degrees C during storage (p<0.05). The polymorphisms of RO appeared to be small, dispersed, plate-like crystals. The BRXO crystal morphology was needle-like and fibrous. All stored samples at both temperatures showed similar morphologies. Regarding EO, the water droplets were dispersed and trapped in the crystal network. Based on the quality parameter results, the bleached rice bran wax can produce stable structured BRXO and W/O emulsions.