Quality of farmed and wild sea bass lipids studied by 1H NMR: Usefulness of this technique for differentiation on a qualitative and a quantitative basis

Usefulness of 1H NMR in assessing the extent of lipid digestion

“…Table 1 shows the assignment of the 1 H NMR signals from the spectra of the samples studied, as shown in Figs. 1 and 2; this assignment is in agreement with previous studies (Guillén & Ruiz, 2001, 2003aGuillén et al, 2008;Nieva-Echevarría et al, 2014;Vidal et al, 2012).…”

“…As in previous studies of edible oils carried out in our laboratory (Guillén, Carton, Goicoechea, & Uriarte, 2008;Martínez-Yusta & Guillén, 2014;Nieva-Echevarría et al, 2014;Vidal, Manzanos, Goicoechea, & Guillén, 2012), 200 ll of the lipid samples were mixed with 400 ll deuterated chloroform (CDCl 3 ), which contains 0.2% of non-deuterated chloroform and a small proportion of tetramethylsilane (TMS) used as internal reference (Cortec, Paris, France). The mixture was introduced into a 5 mm diameter tube.…”

A method based on 1H NMR spectral data useful to evaluate the hydrolysis level in complex lipid mixtures

“…The assignment of their signals, shown in Fig. 1, to the corresponding protons, either of the glyceryl backbone (signals O and S) or of the different acyl chains (signals A, B, C, D1, D2, E, F1, F2, G, H and T) has been very broadly commented on in previous papers and is indicated in Table 2 (Guillén & Ruiz, 2001, 2003aGuillén et al, 2008;Vidal et al, 2012). It is important to note that TG has specific signals (O and S), due to the protons present in the glyceryl backbone.…”

“…In order to select the most appropriate values to obtain accurate quantitative results in the smallest possible period of time, a very broad range of recycling times and relaxation delays were tested in the acquisition of the 1 H NMR spectra. As a result of these tests, the acquisition parameters used were: spectral width 6410 Hz, relaxation delay 3 s, number of scans 64, acquisition time 4.819 s and pulse width 90°, as in previous studies on edible oils and fats carried out in our laboratory (Guillén, Carton, Goicoechea, & Uriarte, 2008;Vidal, Manzanos, Goicoechea, & Guillén, 2012). The relaxation delay and acquisition time allow the complete relaxation of the protons, the signal areas thus being proportional to the number of protons that generate them, being possible their use for quantitative purposes.…”

Bias and Uncertainty in Non-Ideal qNMR Analysis

“…The development of affordable high-field NMR instruments coupled with more elegant pulse sequences has prompted a recent flurry of activity in the field of NMR analysis, ranging from human and plant metabonomic studies (Serkova and Brown, 2012) to analyzing the quality of lipids in wild sea bass (Vidal et al, 2012). A recent review of the applications of qNMR over the past eight years highlights its growing importance in the context of metrology and supports the statement that qNMR can be regarded as a primary method of purity analysis for organic compounds (Pauli et al, 2012).…”