Preparation of Synbiotic Yogurt Sauce Containing Spirulina platensis Microalgae Extract and Its Effect on the Viability of Lactobacillus acidophilus

Abstract

Background. Preparing a healthy and practical substitute for mayonnaise and reducing the complications caused by its consumption are two of the concerns of the producers of this product. Therefore, this study was conducted with the aim of evaluating the possibility of producing synbiotic yogurt sauce prepared with Spirulina platensis microalgae extract (SPAE) as a valuable and alternative product for mayonnaise. Materials and Methods. After preparing yogurt from fresh cow’s milk, synbiotic yogurt sauce was prepared according to the formulation, and the effect of SPAE at the rate of 0.5, 1, and 2% on the viability of the probiotic bacteria Lactobacillus acidophilus was evaluated, and chemical, rheological, and sensory tests were carried out in the storage period (35 days). Results. The highest viability rate of L. acidophilus was related to the treatment containing 2% of SPAE with 1.31 log CFU/g reduction (from 9.02 log CFU/g on the first day to 7.71 log CFU/g on the final day) and 1% of SPAE with 2.98 log CFU/g reduction, respectively, which were significantly more effective than other treatments ($P<0.05$), and it was found that the viability rate increases with the increase in the percentage of the prebiotic composition. There was also a significant difference between the treatments in the simulating conditions of the digestive system, and the viability of L. acidophilus in the treatment containing the prebiotic composition increased ($P<0.05$). According to the results, during storage, in the presence of microalgae, acidity increased, and pH, viscosity, and sensory properties decreased compared to the control group. Upon analyzing the results, it was found that the addition of the prebiotic composition of SPAE, which is known as a functional product, led to a partial improvement in its properties. Therefore, the use of this alga, while benefiting from its medicinal and therapeutic properties, increases the viability rate of probiotic.