Effect of Flaxseed Powder on Physicochemical, Rheological, Microbiological and Sensory Properties of Yoghurt

Abstract

In the presented research, five different ratios of flaxseed powder (FSP) (0, 0.25%, 0.50%, 0.75%, and 1%) were used in yoghurt production, and the samples were stored overall 28 days at refrigerator (+4 °C). The effect of FSP and the storage period on acidity, pH, syneresis, water holding capacity, rheological, viscosity, colorimetric, microbiological, and sensory properties of yoghurts were investigated. The acidity, syneresis values of yoghurt samples decreased with the addition of FSP, conversely, the pH, water holding capacity values of the samples increased. The increments in the viscosity (50 and 100 rpm) and consistency coefficient values were observed depending upon the FSP ratio except for the sample containing 1% FSP. All yoghurt samples had pseudoplastic flow behavior. It was determined that the colorimetric parameters of samples changed significantly with the addition of FSP. The L* and white index values of samples containing FSP decreased. Other colorimetric parameters indicated significant differences based on the addition of FSP and storage. The addition of FSP was not caused any negative effect on counts of Lactobacillus bulgaricus and Streptococcus thermophilus. The Lactobacillus bulgaricus, Streptococcus thermophilus and mouldsyeasts counts were consistent with the Codex Alimentarius and the Turkish Food Codex. The sample containing 1% FSP had the lowest evaluation scores in terms of all sensory properties. Therefore, FSP should not use more than 0.75%. Using of the 0.25% FSP in yoghurts could recommend for improve physicochemical, rheological and sensory properties of yoghurts