Investigation of the Effect of Enzyme Preparation on Water Distribution in Unfermented Dough Under Freeze–Thaw Conditions Using Nuclear Magnetic Resonance Technology

Nuclear Magnetic Resonance (NMR) is an emerging technology in the food industry that enables microscopic-level analysis of moisture distribution and migration in food matrices. T2 inversion spectra indirectly reflect the binding states, relative content, and migration behavior of water in the system.
The following case illustrates the application of NMR in studying how enzyme preparations influence water distribution in frozen-thawed, unleavened dough.
In the figure below, two peaks are observed: – Peak 1 corresponds to tightly bound water, which is closely associated with the internal structures of proteins and starch. – Peak 2 represents semi-bound water, located between protein and starch molecules.
T₂(1) and T₂(2) represent the relaxation times of peaks 1 and 2, respectively. The T₂ value indicates the degree of water mobility — the smaller the value, the more tightly water is bound, resulting in better water-holding capacity of the dough.
The intensity of the proton signal is directly proportional to the number of hydrogen protons, and thus also correlates with the integral area under each peak. Therefore, changes in peak 1 area reflect variations in tightly bound water. The relative content of tightly bound water is calculated as:
Relative Tightly Bound Water (%) = Area of Peak 1 / (Area of Peak 1 + Area of Peak 2)

Effect of Enzyme Preparations on T₂ Relaxation Time and Relative Tightly Bound Water Content in Frozen-Thawed Unleavened Dough

Reference: “Effects of Two Enzyme Preparations on the Quality of Unleavened Dough After Freeze–Thaw Cycles” Transactions of the Chinese Society of Agricultural Engineering, Vol. 31, No. 6, March 2015