Spectral profiles of commercial omega-3 supplements: an exploratory analysis by ATR-FTIR and 1H NMR.

Most of the population is dependent on supplemental products to reach the recommended level of omega-3 polyunsaturated fatty acid (ω-3 PUFA) intake. Thus, knowledge about the quality of ω-3 supplements is important for their safe consumption. In this work, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and nuclear magnetic resonance (NMR) spectroscopy were applied to assess the quality of fourteen commercial ω-3 supplements. Using ATR-FTIR data, we could identify whether ω-3 PUFA was esterified as either triacylglyceride (71%) or ethyl (29%) esters in ω-3 supplements. The type of esterification is rarely included in the product labels, although the consumer should have the right to choose which form of the supplement to consume. On the other hand, 1H NMR spectra were useful to determine the relative concentration of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, and ω-3 PUFA in these commercial samples. Ethyl esters have higher concentrations of unsaturated fatty acids. The NMR results showed a good agreement between the obtained and declared DHA and EPA amounts on the product labels, except for one sample whose high level of ω-3 PUFA indicated it to be a vegetable oil-enriched supplement. Moreover, ω-3 supplements from Schizochytrium sp. microalgae oil revealed higher levels of DHA and ω-3 PUFA, but lower levels of EPA than fish oil. These findings indicate the need for a constant assessment of the quality of commercial products whose ATR-FTIR spectra could be routinely used for the evaluation of PUFA esterification, and NMR analysis could be used to provide advanced quantitative information on commercial ω-3 supplements.

Toward Precision Nutrition: Commercial Infant Formulas and Human Milk Compared for Stereospecific Distribution of Fatty Acids Using Metabolomics.

Precision nutrition and nutrimetabolomics are emerging omics technology applications in public health. In this context, the infant formula (IF) is a manufactured foodstuff that aims to match the composition of human milk (HM), especially the lipid profile. The IF manufacturers have achieved relative success in matching the predominant fatty acid (FAs) profiles, but the stereospecific structures of the triacylglycerides in HM require deeper analyses with system sciences. We employed NMR-based metabolomics to compare the lipid profiles of 12 commercial IF samples and 10 HM samples. Additionally, vegetables, fish, and microalgae oil as raw materials in IFs were also investigated to understand the lipid profile of IFs. We found that IF has significantly less saturated fatty acids (SFA), higher unsaturated FAs, and similar polyunsaturated fatty acid (PUFA) content, compared with HM. However, the main difference was the stereospecific distribution of FAs: HM samples were associated with a high content of SFAs in the sn-2 position (26.03% ± 2.93%) and PUFAs in the sn-1,3 position (15.35% ± 3.94%). The IF had the opposite distribution, with SFAs esterified mainly in the sn-1,3 position (33.07 ± 4.93%) and PUFAs in the sn-2 position (9.57% ± 7.05%). Consequently, the hydrolysis of HM results in SFA mainly as sn-2-monoacylglycerides, which are well absorbed. In contrast, the hydrolysis of the IF provided SFA, mainly as free FAs, which tend to bind calcium and form insoluble calcium soaps in the intestine. Taken together, these observations can inform optimal design of infant formulas with a view to precision nutrition.

Qualitative and quantitative control of pediatric syrups using Nuclear Magnetic Resonance and chemometrics.

Several flavoring and sweetening agents added to excipient of pediatric syrups are not declared in the package leaflet. Therefore, the aim of this study was to develop a non-target, simple, and precise method for qualitative and quantitative evaluation of pediatric syrups using NMR spectroscopy combined with chemometrics. This approach allowed the identification of several added compounds as citric acid, cyclamate, ethanol, glycerol, propylene glycol, saccharin, sorbitol, fructose, glucose, and sucrose. Among the sugared syrups, sucrose was the main carbohydrate with approximately 59.1%, and for sweetened syrups, glycerol with 25.5%. The ethanol was found with highest concentration of 4.0%, approximately. In addition, some syrups presented both sugar and sweetener, which is inconsistent according to the purpose of the addition. Consequently, institutional structures of countries as Brazil that are in charge of public health should put additional compliance pressure on pharmaceutical companies to clearly declare in package leaflet the presence and exact amount of the main compounds (at least) existent in the pediatric excipients.

HR-MAS NMR metabolomics of 'Swingle' citrumelo rootstock genetically modified to overproduce proline.

The accumulation of proline is a typical physiological response to abiotic stresses in higher plants. 'Swingle' citrumelo, an important rootstock for citrus production, has been modified with a mutated Δ(1)-pyrroline-5-carboxylate synthetase gene (VaP5CSF129A) linked to the cauliflower mosaic virus 35S promoter to induce the overproduction of free proline. This paper presents a comparative metabolomic study of nontransgenic versus transgenic 'Swingle' citrumelo plants with high endogenous proline. (1)H high-resolution magic angle spinning nuclear magnetic resonance spectroscopy and multivariate analysis showed significant differences in some metabolites between the nontransgenic and transgenic leaves and roots. The overproduction of proline has reduced the sucrose content in transgenic leaves, revealing a metabolic cost for these plants. In roots, the high level of free proline acts for the adjustment of cation-anion balance, causing the reduction of acetic acid content. The same sucrose level in roots indicates that they can be considered as sucrose sink. Similar behavior may be waited for fruits produced on transgenic rootstock.

Distinction between a transgenic and a conventional common bean genotype by 1H HR-MAS NMR.

In this work, it is proposed a methodology which allows to differentiate a conventional and a specific transgenic common beans, grown in greenhouse or under field conditions, based on modifications in chemical composition using (1)H HR-MAS NMR. It is demonstrated that the influence of typical variables from field planting conditions had no significant influence on the ability to set apart transgenic from conventional. This methodology was corroborated by multivariate data analysis of the (1)H NMR and IR spectra. This study also points out the simplicity of using the HR-MAS NMR technique for food analyses. The measurement is highly simplified because it does not require any pretreatment of the sample apart from the addition of a small amount of D2O necessary to produce homogeneous dough and a field frequency lock. Moreover, due to the high concentration of the sample, measurement time in HR-MAS NMR is very short.