DOI: https://doi.org/10.55373/mjchem.v27i5.224

Keywords: Cookies; whole rice bran; stability; physicochemical properties; antioxidant activity

Abstract

Rice is a staple food for over half of the global population. Rice bran, a by-product of white rice processing, is rich in bioactive components like γ-oryzanol, tocotrienols, and tocopherols, but it is usually discarded or used as animal feed. This study explored the incorporation of whole rice bran in chocolate oat cookies to enhance their nutritional profile. However, the high content of unsaturated fatty acids in rice bran makes it prone to rancidity during storage. The objective of this study was to evaluate the physicochemical properties of the cookies over time when stored at room temperature. A control group of cookies without rice bran and a batch containing 40% rice bran were prepared and analysed at three-week intervals over 15 weeks. The cookies were evaluated for their texture properties, water activity, moisture content, peroxide value, acid value, and total phenolic content. Compared to control cookies, rice bran cookies had higher initial fracturability (3601.13 g vs. 2366.03 g) and hardness (6588.57 g vs. 5937.97 g) (p<0.05). Nevertheless, both cookies underwent comparable losses in fracturability and hardness across storage time. The duration of storage significantly increased the water activity and moisture content. The peroxide value and acid value of stored cookies increased during storage, whereas the highest value was observed in rice bran cookies (11.03 mEq/kg and 1.15%, respectively), indicating increased susceptibility to lipid oxidation. The addition of rice bran significantly increased the total phenolic content in chocolate oat cookies (299.44 mg GAE/100 g vs. 75.37 mg GAE/100 g), even though both formulations were decreased across duration. Although rice bran has the potential to improve the nutrient composition of cookies, careful formulation and appropriate storage conditions are essential to preserving cookie quality.