The Comparsion of the Effect of Spirulina platensis and Chevil (Ferulagoangulata) Extract on the Lactobacilusacidophilus Viability, pH, Syneresis and Color Parametersof Functional Yoghurt

In this study, after the extraction of F.angulata and microalgae Spirulinaplatensis by ultrasound technique and ethanol (99/70 %), levels of 0/1 to 1% of both extracts were injected into milk samples, according to the formulation, and probiotic yogurt containing LactobacillusacidophilusLa-5 wasprepared. Then,determination of pH, color and probiotic count was donewithin 21 days. By increasing the storage time, the pH and syneresis values decreased and increased respectively.Treatments containing different levels of Chevil extract showed lower pH and more syneresis in comparsion with Spirulina extract. Regarding color parameters (L*a*b*), increasing the storage time until the 14th day, the lightness intensity (L*) decreased and the green intensity (a*) of the samples increased. From the 14th day until the end of period, the L* and a* values was increased and decreased respectively.Treatments containing F.angulata extract, had a less L* value and greater a* value than S. platensisextract. The b* value decreased over time, and the highest mean (more yellowness) was related to the treatments containing F.angulata extract. During cold storage until 14 d, L.acidophilus count increased significantly, and then, declined 1 logarithmic cycle, but it was more than the standard number in probiotic yogurt. Treatments containing S. platensisextract showed a higher count of L. acidophilus.The use of S. platensis extract in comparison with F.angulata extract, yielded better results in terms of pH, color and probiotic count. The use of both extracts could improve yogurt color and increase the probiotic count.