Microstructure and viscoelastic properties of low-fat yoghurt structured by monoglyceride gels

Three monoglyceride gels (MG gels) made up by 5 g of monopalmitin/monostearin blends in ratios of 0.10:0.87, 0.30:0.65 and 0.43:0.50, and 0.05 g of an anionic co-surfactant per 100 mL of water were prepared. Differential Scanning Calorimetry (DSC) results indicated that when cooled below the Krafft temperature (T-krafft) the three MG gels were predominantly in the alpha-gel phase, and were used under this condition to prepare three low-fat yoghurt variations (Y-0.1MP,Y-0.87MS, Y-0.3MP,Y-0.65MS, and Y-0.43MP,Y-0.50MS). Scanning electron micrographs showed that Y-0.1MP,Y-0.87MS and Y-0.3MP,Y-0.65MS structure was characterized by aggregated fused casein micelles, which had attached to their surface MG gels, with comparatively smaller interspaced voids than those showed by the control full-fat yoghurt (Y-100). Y-0.1MP,Y-0.87MS and Y-0.3MP,Y-0.65MS exhibited higher viscoelastic parameters over the whole frequency experimental sweep than Y-100. Y-0.43MP,Y-0.50MS, and low-fat control yoghurt (Y-50). (c) 2008 Elsevier Ltd. All rights reserved.