Fortified wheat bread with dried three-phase olive pomace: effect on physicochemical, antioxidant, nutritional, and sensory characteristics.

Abstract

Olive pomace (OP), a key by-product of olive oil production, is recognized as a sustainable and cost-effective source of natural antioxidants. Rich in polyphenols with proven health benefits, OP shows considerable potential for application in functional foods to improve nutritional quality and oxidative stability. This study aims to evaluate the effect of dried OP (dOP) addition on the nutritional, physicochemical, rheological, antioxidant, and sensory properties of fortified wheat bread. Four different replacement levels (1%, 2%, 5%, and 7%) of dOP obtained from the three-phase process of extra-virgin olive oil production were incorporated into the bread. OP exhibited high levels of fiber (38.5%), carbohydrates (33.22%), monounsaturated fats (67.02%), oleic acid (67.78%), phenolic content (23.39 mg GAE/g dw), flavonoids (13.02 mg QE/g dw), and antioxidant activity (15.25 mg Trolox/g dw). The addition of dOP significantly increased phenolic content, flavonoids, and antioxidant activity of breads; the highest values were recorded at 7% dOP (2.34 mg GAE/g dw, 0.32 mg QE/g dw, and 1.10 mg Trolox/g dw, respectively). No significant differences were observed in rheological and most sensory attributes between the control bread and samples fortified with 1% and 2% dOP. However, fortification at high levels (5% and 7%) significantly affected the bread's texture, color, and sensory properties. Additionally, the sensory evaluation showed that bread fortified with 1%, 2%, and 5% dOP exhibited higher overall acceptability compared to the 7% formulation, which demonstrated moderate acceptability due to a slight bitterness and sandy mouthfeel. The results suggest that OP can be utilized as a sustainable and functional ingredient in the formulation of high-value bakery products when added at moderate levels.