Rice Starch as Coating Materials for Microencapsulation of Gamma Oryzanol to Improve its Stability

Gamma Oryzanol (GO) is a phytochemical with the ability to prevent oxidation. GO is normally degraded through oxidation by oxygen and sunlight. Microencapsulation is an important technique used to retard oxidation. This study compared rice starch and Whey Protein Isolate (WPI) as coating materials and investigated the stability of encapsulated GO during storage under activated oxidation conditions. The GO was encapsulated using native rice starch, pregelatinized rice starch, WPI and pregelatinized rice starch combined with WPI (ratio 1:1). The GO concentration, Peroxide Value (PV) and Thiobarbituric Acid Reactive Substance (TBARS) were used to evaluate the effectiveness of the different wall materials. GO encapsulated with pregelatinized rice starch combined with WPI had the greatest stability with the highest GO content (164.54 mg g^-1 sample) remaining after 28 days’ storage and lowest PV and TBARS values. The result indicated that pregelatinized rice starch used either with or without WPI can be applied as wall material to protect GO from oxidation and improve its stability.