Effect of apple fiber enrichment on the structural and functional attributes of stirred yogurt

At the present study, the effect of apple fiber addition (0–3%, w/w) on the physicochemical, rheological, antioxidant and sensory properties of yogurt was investigated. The addition of apple fiber increased total solids and water holding capacity (15.6 % and 17.3% respectively at day 28), while reduced syneresis (18% at day 28) in a concentration-dependent manner that improved structural stability. Strong correlation was confirmed due to significantly increased total phenolic content and antioxidant activity. The rheological analyses showed that moderate fiber levels (1–2%) strengthened the gel network (higher G′, lower tan δ), while excessive addition (3%) disrupted structure and reduced viscoelastic moduli. Sensory evaluation revealed a decrease in smoothness and overall acceptability at higher fiber levels, although enrichment at 1% maintained acceptable sensory quality. The addition of apple fiber can be considered as a potential sustainable functional ingredient since it enhanced yogurt functionality and proved sensory accepted. • Apple fiber modified yogurt texture, structure, and stability. • Moderate fiber addition (1–2%) enhanced gel strength and water holding capacity. • High fiber addition (3%) weakened gel structure and reduced sensory acceptability. • Apple fiber increased total phenolic content and antioxidant activity. • Apple fiber supports functional yogurt and valorization of fruit by-products.