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 (Tkrafft) the three MG gels were predominantly in the α-gel phase, and were used under this condition to prepare three low-fat yoghurt variations (Y0.1MP,0.87MS, Y0.3MP,0.65MS, and Y0.43MP,0.50MS). Scanning electron micrographs showed that Y0.1MP,0.87MS and Y0.3MP,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 (Y100). Y0.1MP,0.87MS and Y0.3MP,0.65MS exhibited higher viscoelastic parameters over the whole frequency experimental sweep than Y100, Y0.43MP,0.50MS, and low-fat control yoghurt (Y50).