A 1H Nucear Magnetic Resonance Study of the Changes Occurring During Pound Cake Storage
During storage at ambient temperatures, cake crumb gradually firms. This can partly be ascribed to water migration from crumb to crust. Such moisture migration and water incorporation in starch crystals can be monitored with 1 dimensional 1H NMR. In previous work using model systems, we successfully assigned 1H NMR peaks to different components present in cake batter and produced a complex fingerprint with four different peaks. In this study, cake crumb samples were withdrawn at different time intervals during storage and water migration was monitored with 2 dimensional 1H NMR. This enabled us to further differentiate the two most mobile peaks from the 1 dimensional profile into respectively two and three different peaks. During cake storage, spin spin as well as spin lattice relaxation times decreased for peaks containing exchangeing protons (i.e. protons of water, starch, gluten, egg proteins and sugar). Strong negative correlations were found between the relaxation times (measured with 2 dimensional 1H NMR) and crumb firmness (measured with texture analysis) and amylopectin melting enthalpy (measured with differential scanning calorimetry). We found 2 dimensional 1H NMR to be useful for studying cake ageing.