Improving the Textural Properties of Yogurt Fortified with Milk Proteins

In this study, the changes in the physicochemical, textural and sensory properties of nonfat yogurts fortified with milk proteins; namely sodium caseinate (Na-CN), calcium caseinate (Ca-CN) and milk protein concentrates (MPCs) were investigated. Enrichment of nonfat yogurt with the milk protein additives had a noticeable effect on pH, titratable acidity, whey separation, water holding capacity (WHC), protein contents and color values as well as textural attributes such as hardness, adhesiveness and cohesiveness (P < 0.01). It can be seen that the addition of milk proteins have increased the WHC and decreased whey separation. Using milk proteins in yogurt manufacturing processes caused a more compact structure consisting of stiff casein particles and large aggregates along with increased hardness which also increase cohesiveness and elasticity values resulting in improved textural properties. Also chromatic parameters (L*, a*, b*, ΔE, h*, and C*), were affected by protein supplementation. The taste of samples enriched with milk proteins were more appreciated than control yogurt. These findings confirm that milk protein additives can play a beneficial role in improving textural properties of set type nonfat yogurt and can be used to develop functional dairy products. Practical Applications Yogurt is a popular fermented milk product of the human diet, due to their high nutritional value and their appealing sensory and textural properties. Textural properties of yogurt are known to have an important parameter on sensory and acceptability of yogurt. However, reduction of fat and total solids content in low fat and nonfat yogurts, exhibit weak texture, poor sensory properties. The aim of this study was to search the effects of using milk proteins on physicochemical, textural and sensory properties of nonfat yogurts. The results indicated that milk proteins caused an increase in density of the protein matrix with the structural building properties and improved textural properties.