Investigation of The effect of Phycocyanin Extracted From Spirulina platensis and Persimmon Powder on Physicochemical and Sensory Characteristics of Yogurt

Abstract

Yogurt is one of the most widely consumed fermented products obtained from milk that has a positive effect on health due to its high nutritional value. Yogurt enrichment can play a major role in the developmentof consumers’ health level. Spirulina platensisis a blue-green microalga and is rich in protein, essential fatty acids, vitamins, minerals and antioxidant compounds, such as phycocyanin. The aim of the present study was to investigate the effect of phycocyanin extracted from S. platensis and persimmon powder on physicochemical and sensory characteristics of yogurt. For this purpose, the yoghurt samples were analyzed for their physicochemical characteristics. Samples without persimmon powder and containing higher amounts of phycocyanin (1% and 1.5%) had the highest acidity. The acidity values of all samples increased over time. The highest pH belonged to the control sample and the addition of different amounts of phycocyanin and persimmon powder caused a significant reduction in pH.In all time intervals, with the increase of persimmon powder and phycocyanin, the syneresis rate of samplesincreased though it was not significant compared to the control sample. Samples containing higher amounts of persimmon powder (codes 6 and 7) had higher dry matter, protein, and water holding capacity (WHC).On both studied days, the highest and the lowest viscosity belonged to treatment code 7 andcode 2, respectively (p≤0.05). Additionally, the viscosity of all treatments increased significantly from the first day to the fifteenth day over time (p≤0.05). The control sample had the highest lightness (L* ) and the treatment code 8 had the highest redness (a * ‌). In all time intervals, the highest hardness and springiness belonged to the control sample (p≤0.05). The results of sensory evaluation of the samples showed that on the first day, the color score of the control sample and treatment codes 5, 6 and 7 was significantly higher than other treatments (p≤0.05). On all days studied, the taste scores of the control sample and treatment codes 5 and 6 and the texture score of the control sample and treatment codes 6, 7, and 8 were significantly higher than other treatments (p≤0.05).Considering the sensory evaluation and protein content of the yogurt samples, treatment code 6 was selected as the best treatment. The results showed that phycocyanin extracted from S. platensis and persimmon powder is effective on the physicochemical and sensory properties of yogurt and can be used as an effective additive.