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

Abstract

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.