Microstructural changes in condensed milk with the starch syrup during prolonged storage: an electron microscopy study

These work deals with the study of changes in the microstructure of the sweetened condensed milk with sugar substitution for starch syrup during its long storage period. The research has been carried out with the transmission electron microscope. The authors have analyzed the microstructure of the condensed milk with sugar and the microstructure of the condensed milk with ۴۰% and ۱۰۰% sugar substitution for the starch syrup. It is established that filamentous bridges are formed between the casein micelles in the microstructure of the condensed milk with the partial sugar substitution for the starch syrup. These bridges are pseudo-polymers, formed by glucose monomers. During the long-storage period the number and density of these bridges increase, influencing, consequently, the organoleptic and rheological properties of the condensed milk. The studies have shown that there is a critical concentration of the starch syrup in the condensed milk, which limits the syrup use in the manufacture of the product.