Syneresis, Texture and Microbiological Quality of Yoghurt After the Addition of Blackberry (Rubus fruticosus)

This study evaluated the effect of blackberry pomace extract (Rubus fruticosus) on the microbiological quality, water holding capacity (WHC), and texture of set-type yoghurt. Four formulations were prepared: a control and three experimental groups supplemented with the extract at concentrations of 0.5%, 0.75%, and 1% prior to fermentation. Streptococci and lactobacilli viability, WHC, and firmness were assessed one day after production and after 7 days of storage at 6 °C. All samples maintained viable counts above 7 log CFU.g⁻¹ throughout storage, with values remaining stable at approximately 8 log CFU.g⁻¹. No statistically significant differences (p > 0.05) were observed in WHC or firmness between control and enriched yoghurts. The results indicate that blackberry pomace extract can be incorporated into set-type yoghurt without adversely affecting microbiological stability or key texture-related properties.