Development of a stabilizer for set-yogurt production containing gelatin, modified starch and guar gum

One of the most important sensorial attributes of yogurt is texture, which could be assessed by sensory or instrumental analysis. Stabilizers are used to improve consistency (increase viscosity) and reduce syneresis in yogurt. This study was a practice to formulate a stabilizer for set-yogurt by adding gelatin (0-0.3%), modified starch (0-0.3%) and guar gum (0-0.04%) through a Central Composite Design in order to improve texture of the product. Texturizing ingredients’ amounts were obtained by preliminary experiments. By mixing the ingredients in powder status thoroughly, they were added to the standardized and homogenized milk containing 2.5% fat at 65 °C while stirring and allowed to hydrate for 15 min. Then the milk was pasteurized batch-wise (10 min at 90 °C), cooled to fermentation temperature (42 °C) and subsequently inoculated with starter culture. The apparent viscosity (using a Brookfield viscometer), syneresis and water-holding capacity (by centrifuging) were monitored for each treatments. The addition of thickeners increased all the studied sensory texture attributes significantly. The optimum formulation for set-yogurt production was obtained as follows: gelatin amount three fold more than modified starch and guar gum 0.03%.

Keywords:

yogurt , texture , gelatin , modified starch , guar gum