Enrichment of set yoghurt with flaxseed oil, flaxseed mucilage and free or encapsulated Lacticaseibacillus casei: Effect on probiotic survival and yoghurt quality attributes

This study was intended to develop yoghurt products incorporated with flaxseed mucilage (FM), flaxseed oil (FO) and free or encapsulated Lacticaseibacillus casei probiotics. FM (0.9%) and sodium alginate (2%) were used as wall materials for encapsulating L. casei. Different physicochemical and sensory properties of the yoghurt, as well as the L. casei survival, were determined during 21 days of storage at 4 °C. Based on the results, FM showed a stimulatory effect on the growth of probiotics and thus, significantly decreased the Log reduction of the probiotics during storage (P < 0.05). Moreover, encapsulating probiotics significantly decreased the Log reduction during storage in comparison with the free bacteria (P < 0.05). Incorporating FM and free probiotics significantly increased the acidity and decreased the pH of the samples; while encapsulating L. casei successfully prevented the acidity increment in probiotic fortified yoghurt products (P < 0.05). The addition of FM significantly improved the water holding capacity of the yoghurt (P < 0.05). Incorporating either free L. casei, FO or FM significantly reduced the flavor and overall acceptance scores; while, the addition of L. casei in the encapsulated form did not significantly alter the overall acceptance scores of the yoghurt samples (P < 0.05).