1H NMR Study of the In Vitro Digestion of Highly Oxidized Soybean Oil and the Effect of the Presence of Ovalbumin

Abstract

Oxidized lipids containing a wide variety of potentially toxic compounds can be ingested through diet. However, their transformations during digestion are little known, despite this knowledge being essential in understanding their impact on human health. Considering this, the in vitro digestion process of highly oxidized soybean oil, containing compounds bearing hydroperoxy, aldehyde, epoxy, keto- and hydroxy groups, among others, is studied by 1H nuclear magnetic resonance. Lipolysis extent, oxidation occurrence and the fate of oxidation products both present in the undigested oil and formed during digestion are analyzed. Furthermore, the effect during digestion of two different ovalbumin proportions on all the aforementioned issues is also addressed. It is proved that polyunsaturated group bioaccessibility is affected by both a decrease in lipolysis and oxidation occurrence during digestion. While hydroperoxide level declines throughout this process, epoxy-compounds, keto-dienes, hydroxy-compounds, furan-derivatives and n-alkanals persist to a great extent or even increase. Conversely, a,b-unsaturated aldehydes, especially the very reactive and toxic oxygenated ones, diminish, although part of them remains in the digestates. While a low ovalbumin proportion hardly affects oil evolution during digestion, at a high level it diminishes oxidation and reduces the concentration of potentially bioaccessible toxic oxidation compounds.

Influence of Hydroxytyrosol Acetate Enrichment of an Oil Rich in Omega-6 Groups on the Evolution of Its Oxidation and Oxylipin Formation When Subjected to Accelerated Storage. A Global Study by Proton Nuclear Magnetic Resonance

“…The occurrence of this type of reaction has become evident because the spectra of the samples studied show spectral signals due to the protons of the ester group formed in the case of formic acid, that is to say, of formats. The formate group has characteristic spectral signals (see Table S14), which have been detected previously in studies on polymerization of oils [127], and recently for the first time in 1 H NMR spectra of edible oils subjected to oxidative conditions [32,115,138]. From their intensity (see Table S14), the formate concentration in the different samples throughout storage was estimated and plotted versus storage time in Figure 17b.…”

Quality Evaluation of Fresh Pasta Fortified with Sourdough Containing Wheat Germ and Wholemeal Semolina

“…Other relevant signals can be observed from 5.5-6.6 ppm and at about 7.5-8.0 ppm (Figure 2). According to the literature, the most representative signals from primary lipid oxidation products are expected to appear in the 3.3-5.3 ppm spectral region (Figure S2) [62][63][64][65]. A-C) peaks from keto groups or alkyl-furanones [64].…”

“…According to the literature, the most representative signals from primary lipid oxidation products are expected to appear in the 3.3-5.3 ppm spectral region (Figure S2) [62][63][64][65]. A-C) peaks from keto groups or alkyl-furanones [64]. For details about the region 3.3-5 ppm, see Supplementary Materials (Figure S2).…”

“…However, experiment evidence (Figure 3) demonstrates that primary oxidation of lipids is present in pasta at t same level across time, with very tiny sample-dependent changes, ruling out an accumulating phenomena of oxidized lipids (Figure S3). When the differently formulat A-C) peaks from keto groups or alkyl-furanones [64]. For details about the region 3.3-5.3 ppm, see Supplementary Materials (Figure S2).…”

“…When the differently formulated pasta samples were compared at the same storage time, CP always had higher amounts of oxidized lipid moieties than SP and RGP, the latter two showing almost identical concentrations of such species. A-C) peaks from keto groups or alkyl-furanones [64]. For details about the region 3.3-5.3 ppm, see Supplementary Materials (Figure S2).…”