Effect of particle size and concentration of defatted rice bran supplemented in tomato salad dressing

Defatted rice bran (DRB) is a low-cost, high-fiber, antioxidant-rich byproduct of rice bran oil production that has limited application in food systems due to its undesirable impacts on sensory attributes. This research aimed to determine the feasibility of integrating defatted rice bran into tomato salad dressing without undergoing chemical or enzymatic pretreatment. The DRB particle size (38, 90, and 150 µm) and concentration (1, 5, and 9%) significantly affected the functional properties and sensory attributes of salad dressing. The high bran concentration significantly increased viscosity and emulsion stability, although it had the opposite effect on color and texture sensory characteristics (p < 0.05). The particle size of bran significantly affected the appearance, texture, and overall liking of the product. The response surface methodology showed that the optimal DRB particle size and concentration for supplementation in a tomato salad dressing were 75 µm and 4.80%, respectively. The DRB supplementation prolonged the oxidative stability of the product compared to its control counterpart. Results demonstrated that the particle size reduction adequately modified the DRB properties to be suitable for application as a functional ingredient, which enhanced the nutritional properties and storage stability of a salad dressing.