The effects of different levels of Spirulina platensis extract on qualitative and microbiological properties and viability of probiotic bacteria in probiotic dairy dessert

Dairy products have a large share of the world market for healthy foods, and enrichment of these products with physiologically active ingredients such as probiotics or other functional ingredients has received much attention. Spirulina platensis is one of these bioactive compounds and has many antioxidant, antimicrobial and nutritional properties so its use in food formulations can improve the nutritional and sensory properties and reduce the use of chemical preservatives and thus increase shelf life of products. In the present study, the production of probiotic dairy desserts containing microalgae extract of Spirulina platensis (at three levels of 0.5, 1 and 1.5%) and the effect of microalgae on increasing the survival of probiotic bacteria Lactobacillus acidophilus and Bifidobacterium lactis were investigated Also, the quality characteristics of the dessert such as pH, emulsion stability and sensory properties as well as the microbial properties of the product were studied. The results showed a positive effect of spirulina extract in improving the qualitative, sensory and microbial properties of the product so that increasing the concentration of the extract showed a direct relationship with the stability of the samples and reduced the syneresis in them Also, samples containing 1percent spirulina extract received the highest overall sensory acceptance score The results of microbial examinations showed that with increasing the concentration of the extract, the total bacterial count, mold and yeast count and coliform and Staphylococcus bacteria decreased compared to the control treatment The survival of probiotic bacteria during storage period was also improved by the addition of spirulina.