Physical, chemical and flavour quality of non-fat yogurt as affected by a β-glucan hydrocolloidal composite during storage

Abstract

In this study, a possible use of β-glucan hydrocolloidal composite as a fat replacer in the manufacture of non-fat yogurts was investigated. The yogurts with added β-glucan composite were compared with non-fat yogurt without addition of β-glucan composite and the samples were analysed for physical, chemical and sensory attributes after 1, 7 or 15 d of storage. Fat and protein contents of the experimental yogurts were identical, while ash content differed. Addition of β-glucan composite did not show a significant change of pH, titratable acidity, acetaldehyde, volatile fatty acids and tyrosine contents at any storage time. Titratable acidity and tyrosine content increased significantly throughout storage. Gel firmness and water-holding capacity in the yogurts were not influenced by addition of β-glucan composite, but these variables decreased with storage time. Addition of β-glucan composite and storage time caused a decrease in whey separation. Viscosity values in the yogurts increased by addition of β-glucan composite and storage time. Sensory results indicated a preference for control yogurts; however, use of low levels of β-glucan composite in the production of non-fat yogurt gave satisfactory sensory scores. Yogurts containing 0.25% or 0.50% β-glucan hydrocolloidal composite were acceptable by expert panels and had scores similar to the control yogurt.