The Effect of Stabilized Rice Bran Addition on Physicochemical, Sensory, and Techno-Functional Properties of Bread

Abstract

Rice bran (RB) is a valuable byproduct derived from rice milling that represents an excellent opportunity for dietary inclusion. Bioactive components with antioxidant potential have been reported in RB, gaining the considerable attention of researchers. However, RB requires a stabilization process after milling to prevent it from becoming rancid and promote its commercial consumption. The aim of this study was to evaluate the effects of substituting stabilized rice bran (SRB) for wheat flour at levels of 10, 15, 20 and 25% on the proximate composition, dietary fiber, dough rheology, antioxidant properties, content of bioactive compounds, and sensory attributes of white wheat-based bread. Results indicated that the incorporation of SRB increased the bread's insoluble dietary fiber, phytic acid, total polyphenol content, γ-oryzanol, γ-aminobutyric acid, and antioxidant properties, while decreased its water absorption capacity, elasticity, volume, β-glucans, and soluble dietary fiber content. Moreover, substituting wheat flour for SRB at levels higher than 15% affected sensory attributes, such as color, odor, flavor, and softness. This study highlights the potential application of SRB flour in bread-making to increase nutritional, and functional properties of white wheat bread.

Keywords: Oryza sativa; bioactive compounds; bread; functional foods; rice bran.

Figure 1

Breads formulated with different percentages of SRB. Abbreviations: 10SRB: formulation with 10% of SRB; 15SRB: formulation with 15% of SRB; 20SRB: formulation with 20% of SRB; 25SRB: formulation with 25% of SRB. The scale of the figure is in cm.

Figure 2

Total phenolic compounds (mg GAE/100 g d.m.), γ-oryzanol (mg/100 g) and GABA (mg/100 g) content in white wheat bread with stabilized rice bran (SRB) (n = 3). Abbreviations: 10SRB, formulation with 10% of SRB; 15SRB, formulation with 15% of SRB; 20SRB, formulation with 20% of SRB; 25SRB, formulation with 25% of SRB. The different lowercase letters indicate significant difference among mean values within a same compound (p ≤ 0.05 according to Duncan’s test).

Figure 3

Antioxidant activity in white wheat bread with stabilized rice bran (SRB) (n = 3). Abbreviations: 10SRB, formulation with 10% of SRB; 15SRB, formulation with 15% of SRB; 20SRB, formulation with 20% of SRB; 25SRB, formulation with 25% of SRB. The different lowercase letters indicate significant difference among mean values (p ≤ 0.05 according to Duncan’s test).

Figure 4

Sensory analysis of white wheat bread formulated with different levels of stabilized rice bran (SRB). Abbreviations: 10SRB, formulation with 10% of SRB; 15SRB, formulation with 15% of SRB; 20SRB, formulation with 20% of SRB; 25SRB, formulation with 25% of SRB.