NMR assessment of ice cream: Effect of formulation on liquid and solid fat

The capacity of low field NMR spectrometry to characterize the different behaviours of fat protons in unfrozen ice cream mix and in ice cream was investigated. Various formulations comprising different types of fat, protein and emulsifier were tested. The NMR parameters attributed to fat were sensitive both to the type of fat and also to the components located at the fat globule interface. In the unfrozen ice cream mix and to a lesser extent in ice cream, liquid fat was more sensitive to the type of protein, whereas the solid fat was sensitive to the type of emulsifier. The solid to liquid fat ratio calculated from the solid part of the NMR signal in the unfrozen mix was mainly dependent on the fat and emulsifier types. Changes in the states of liquid fat were detected during cold storage and interpreted as deviation from an equilibrium state recoverable after prolonged storage.