Effects of quinoa addition on physicochemical, microbial and sensory properties of stirred yogurt

The consumption of fermented milk products, including yogurt, has been increased dramatically as people become aware of the functional and health resources. Quinoa seeds have recently received more attention due to their favorite nutritional properties and high content of protein, amino acids, fatty acids, minerals, and essential vitamins. Therefore, in this study, the fortification of beneficial yogurt with quinoa and its effect on physicochemical and microbial and organoleptic properties of product were investigated. Flour of quinoa seeds were added to yogurt milk at three levels (2, 4, and 6%). A sample of each treatment is selected every week and were analysed with respect to physicochemical (texture, pH, acidity, dry matter, hydration, etc.), microbial (starter count and yeast mold), and sensory properties compering to control samples. Based on the results of physicochemical tests, addition of quinoa flour significantly reduced syneresis, pH, and increased acidity, dry matter, viscosity, fiber, fat, and ash contents. The evaluation of color of samples showed that L index decreased while a and b indexes increased significantly with increasing the percentage of quinoa flour. On the other hand, the starters counts increased in fortified samples due to the nutrients of quinoa. Sensory properties were not significantly different between fortified and control sample except of texture that was improved with quinoa addition. The results of this study showed that the use of quinoa flour in stirred yogurt can led to producing a product with desirable and functional characteristics.