*3.9. LF NMR Relaxometry*

Biscuit samples were placed in Ø8 mm measuring tubes. The height of the sample in the tube was set at 15 mm. After placing the samples, the tubes were closed with Parafilm® and measurements were made.

<sup>1</sup>H NMR relaxation times (spin–lattice (T1) and spin–spin (T2)) were analyzed with a pulse NMR spectrometer PS15T operating at 15 MHz (Ellab, Pozna´n, Poland) at 21.0 ± 0.5 ◦C. The inversion–recovery (π − τ − π/2) [100] pulse sequence was applied for measurements of the T<sup>1</sup> relaxation times. Distances between RF pulses (τ) were changed within the range from 0.5 to 50 ms and the repetition time was from 15 s. Each time, 32 FID signals and 110 points from each FID signal were collected. Calculations of the spin–lattice relaxation time values were performed with the assistance of the CracSpin program [101].

Measurements of the spin–spin (T2) relaxation times were taken using the pulse train of the Carr–Purcell–Meiboom–Gill spin echoes (π/2 − TE/2 − (π)<sup>n</sup> [100]. The distance (TE) between π RF pulses ranged from 0.1 to 1.0 ms. The repetition time was 15 s. The number of spin echoes (n) amounted to 100. Five accumulation signals were employed. The calculations were performed by using the dedicated software by application of a non-linear least-square algorithm.
