Effect of olive leaves powder supplementation on quality attributes and antioxidants of fresh milk cheese

Background: Fortifying cheese with olive leaves powder, presents an innovative approach allowing the improvement of quality attributes of dairy products. Olive leaves, a co-product of olive oil production, are rich in bioactive compounds, which are known for their antioxidant, antimicrobial, and anti-inflammatory properties. Objectives: This study aimed to evaluate the effect of olive leaf powder supplementation on fresh cheese quality attributes. Methods and Results: Three formulations of fresh cheese made from cow milk and supplemented with olive leaves powder (0.5, 1, 1.5%) were prepared and compared to not-supplemented fresh cheese. The incorporation of the olive leaves powder did not affect the physicochemical characteristics of cheese, except for colorimetric parameters and fat and ash contents. However, it positively affects antioxidant content and activity. The incorporation of olive leaves powder at different levels (0.5, 1, and 1.5%) in fresh cheeses enhances the content of phenols (54.17%, 59.26%, and 64.52%, compared to control cheese). The same trend was found for the antioxidant activity. Sensory analysis showed that some sensory descriptors significantly changes, such as color, odor, taste, and after-taste. The fresh cheese supplemented with 0.5% olive leaf powder is the most appreciated one, suggesting that olive leaves could be used in fortifying cheese and promoting consumers’ antioxidant defense. Novelty: This study presents a novel approach to fortifying fresh cheese with olive leaf powder (OLP) to enhance antioxidant properties while preserving the key quality attributes. OLP significantly increases phenolic content and antioxidant activity without compromising physicochemical attributes. Sensory analysis reveals that cheese with 0.5% OLP offers the best consumer acceptance, highlighting its potential as a functional dairy product. This innovative use of OLP supports the development of healthier dairy alternatives in response to growing consumer demand Keywords: olive leaves, antioxidants, fresh cheese, sensory properties, chemical properties.