Evaluation of Psyllium (Plantago ovata L.) Husk Powder as a Stabilizer in Coconut Milk-Based Probiotic Yogurt Production

Plantago ovata L., also known as psyllium, is a plant native to the Mediterranean that is commercially cultivated and utilized for its polysaccharides, which have an arabinoxylan structure. Psyllium seeds possess various functional characteristics due to strong hydrophilic and gelling properties, as well as stabilizing and emulsifying capabilities. This study evaluated the use of psyllium (P. ovata L.) husk powder (PHP) as a stabilizer in the production of probiotic plant-based yogurt from coconut milk. The physicochemical, microbiological, textural, rheological, microstructural, and sensory properties of yogurt samples produced by adding different amounts of PHP (control, 0.125%, 0.25%, and 0.5%) during the storage period were analyzed. The produced plant-based yogurts contained 72.80%–76.03% moisture, 18.30%–18.89% fat, 1.81%–2.03% protein, and 0.41%–0.44% ash. As the proportion of PHP and storage time increased, pH, and syneresis generally decreased and titratable acidity increased. The sample containing 0.5% PHP exhibited the highest microbiological counts. The addition of PHP to samples decreased L*, b*, C*, and h values and increased a* values. As the proportion of PHP increased, a significant increase in particle size parameters was detected. A more stable, homogeneous, and dense gel structure appeared in products with 0.25% PHP addition. The addition of PHP decreased hardness and adhesiveness while increasing cohesiveness. All samples exhibited a weak viscoelastic gel property (G′>G″). As the proportion of added PHP increased, the storage modulus decreased. Samples containing 0.25% PHP were rated higher in terms of sensory attributes, including taste, texture, and overall acceptability. Hierarchical cluster and principal component analyses were employed to categorize the yogurts, revealing that the control sample exhibited distinct characteristics compared to the psyllium-added yogurts in terms of the aforementioned properties. The results show that, when added in the right amounts, PHP can stabilize the production of probiotic yogurt-like products from coconut milk.