Determination of food emulsifiers in commercial additives and food products by liquid chromatography/atmospheric-pressure chemical ionisation mass spectrometry

Determination of E 472b emulsifiers in foamed food formulations by high-performance thin-layer chromatography‒fluorescence detection

E 472b emulsifiers, defined as lactic acid esters of mono- and diacylglycerides, are food emulsifiers widely used in foamed food formulations. So far, only qualitative methods for analyzing E 472b emulsifiers have been published. Thus, a new method was developed for determining E 472b in different foamed food formulations by high-performance thin-layer chromatography with fluorescence detection (HPTLC‒FLD). The proposed method allows simple and fast E 472b emulsifier extraction from the food matrix and points out an analytical approach for quantifying these emulsifiers using a commercial E 472b emulsifier as the reference standard. Limits of decision with 56‒59 ng of E 472b emulsifier/zone and limits of quantification with 172‒179 ng of E 472b emulsifier/zone in three foamed model food formulations, respectively, as well as satisfactory repeatability (n = 6) and reproducibility (n = 6) exposed by low relative standard deviation < 8% proved the method suitable for the sensitive and reliable determination of E 472b emulsifiers. Recoveries between 96 and 109.3% were obtained for all investigated model systems. In commercial foamed food formulations from the German market, the E 472b emulsifier content ranged between 0.1 and 0.6 g/100 g.

Analysis of mono-, di-, triacylglycerols, and fatty acids in food emulsifiers by high-performance liquid chromatography–mass spectrometry

Mono- and diacylglycerols (MG/DG) of fatty acids (FA), known as emulsifiers of the type E 471, are food additives used to adjust techno-functional properties of various foodstuffs. These emulsifiers, however, are not defined single compounds but comprise, in addition to MG and DG, other constituents such as FA, triacylglycerols (TG), and glycerol. Although the emulsifiers’ compositions affect techno-functional properties of the food, knowledge of the composition is scarcely available, and the emulsifiers and their dosage are generally chosen empirically. Thus, a simple and rather inexpensive method for the simultaneous determination of FA, 1-MG, 2-MG, 1,2-DG, 1,3-DG, and TG by high-performance liquid chromatography–mass spectrometry including a straightforward quantitation strategy has been developed. Reversed-phase chromatography with gradient elution offered adequate separation of 29 considered analytes within 21 peaks, while mass-selective detection provided their unequivocal identification. The quantitation strategy based on calibration just with the C16:0 representatives of each lipid class and a corresponding response factor system has proven to provide reliable results. The determined concentrations of different mixtures comprising varying compositions and concentrations of C16:0, C18:0, and C18:1 components of each lipid class deviated < 20% (n = 351) from the respective target concentrations. Limits of decision were determined to 0.3–0.8 mg/L and limits of quantitation to 0.8–1.7 mg/L, expressed as C16:0 representatives. Application of the method to various E 471 emulsifiers provided detailed data on their chemical compositions, and calculated FA compositions matched very well those determined by common methods such as gas chromatography with flame ionization detection.

Rice Bran By-Product: From Valorization Strategies to Nutritional Perspectives

The aim of this study is to review the innovative techniques based on bioprocessing, thermal or physical treatments which have been proposed during the last few decades to convert rice bran into a valuable food ingredient. Rice bran (Oryza sativa) is the main by-product of rice grain processing. It is produced in large quantities worldwide and it contains a high amount of valuable nutrients and bioactive compounds with significant health-related properties. Despite that, its application in food industry is still scarce because of its sensitivity to oxidation processes, instability and poor technological suitability. Furthermore, the health-related effects of pretreated rice bran are also presented in this review, considering the up-to-date literature focused on both in vivo and in vitro studies. Moreover, in relation to this aspect, a brief description of rice bran arabinoxylans is provided. Finally, the application of rice bran in the food industry and the main technology aspects are concisely summarized.

Determination of mono- and diacylglycerols from E 471 food emulsifiers in aerosol whipping cream by high-performance thin-layer chromatography-fluorescence detection

Mono- and diacylglycerol (MAG and DAG) emulsifiers (E 471) are widely applied to regulate techno-functional properties in different food categories, for example, in dairy products. A method for the determination of MAG and DAG in aerosol whipping cream by high-performance thin-layer chromatography with fluorescence detection (HPTLC-FLD) after derivatization with primuline was developed. For sample preparation, aerosol whipping cream was mixed with ethanol, followed by the addition of water and liquid-liquid extraction with tert-butyl methyl ether. The sample extracts were analyzed by HPTLC-FLD on silica gel LiChrospher plates with n-pentane/n-hexane/diethyl ether (22.5:22.5:55, v/v/v) as mobile phase, when interfering matrix like cholesterol and triacylglycerols were successfully separated from the E 471 food additives. For quantitation, an emulsifier with known composition was used as calibration standard and the fluorescent MAG and DAG were scanned at 366/> 400 nm. Limits of detection and quantitation of 4 and 11 mg/100 g aerosol whipping cream were obtained for both monostearin and 1,2-distearin, respectively, and allowed the reliable quantitation of MAG and DAG from E 471 far below commonly applied emulsifier amounts. Recoveries from model aerosol whipping cream with 400 mg E 471/100 g were determined in a calibration range of 200-600 mg E 471/100 g sample and ranged between 86 and 105% with relative standard deviations below 7%. In aerosol whipping creams from the German market, E 471 amounts ranged between 384 and 610 mg/100 g.

Re-evaluation of acetic acid, lactic acid, citric acid, tartaric acid, mono- and diacetyltartaric acid, mixed acetic and tartaric acid esters of mono- and diglycerides of fatty acids (E 472a-f) as food additives

The Panel on Food Additives and Flavourings (FAF) provided a scientific opinion re-evaluating the safety of acetic acid, lactic acid, citric acid, tartaric acid, mono- and diacetyltartaric acids, mixed acetic and tartaric acid esters of mono- and diglycerides of fatty acids (E 472a-f) as food additives. All substances had been previously evaluated by the Scientific Committee for Food (SCF) and by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). Hydrolysis of E472a,b,c,e was demonstrated in various experimental systems, although the available data on absorption, distribution, metabolism, excretion (ADME) were limited. The Panel assumed that E472a-f are extensively hydrolysed in the GI tract and/or (pre-)systemically after absorption into their individual hydrolysis products which are all normal dietary constituents and are metabolised or excreted intact. No adverse effects relevant for humans have been identified from the toxicological database available for E472a-f. The Panel considered that there is no need for a numerical acceptable daily intake (ADI) for E 472a,b,c. The Panel also considered that only l(+)-tartaric acid has to be used in the manufacturing process of E472d,e,f. The Panel established ADIs for E 472d,e,f based on the group ADI of 240 mg/kg body weight (bw) per day, expressed as tartaric acid, for l(+)-tartaric acid-tartrates (E334-337, 354) and considering the total amount of l(+)-tartaric acid in each food additive. Exposure estimates were calculated for all food additives individually, except for E 472e and f, using maximum level, refined exposure and food supplements consumers only scenarios. Considering the exposure estimates, there is no safety concern at their reported uses and use levels. In addition, exposure to tartaric acid released from the use of E 472d,e,f was calculated. The Panel also proposed a number of recommendations.

High-performance liquid chromatography and gas chromatography to set the analysis method of stearoyl lactylate, a food emulsifier

Stearoyl lactylates (SLs, E481/E482) and their sodium and calcium salts are emulsifiers commonly used as food additives. This study was performed to set the analytical method of SLs in Korea using high-performance liquid chromatography (HPLC) and gas chromatography (GC). A new HPLC method using C18 column with water and methanol as the eluents, and a new GC method using DB-1 column with He as the carrier gas, were developed and were compared with previously reported analytical methods. The new HPLC and GC methods indicated a coefficient of determination (r²) of 0.999 in the calibration curves. The detection and quantification limits are 0.26 and 0.78 μg/kg for the HPLC method, respectively, and 16.54 and 50.12 μg/kg for the GC method, respectively. The new HPLC and GC methods indicated precision of 0-2.0%, and accuracy of 92.7-108.5%. Therefore, they can be applied in numerous food samples to determine the level of SLs.

Identification of lipophilic ligands of Siglec5 and -14 that modulate innate immune responses

Sialic acid-binding immunoglobulin-like lectins (Siglecs) are a family of cell-surface immune receptors that bind to sialic acid at terminal glycan residues. Siglecs also recognize nonsialic acid ligands, many of which remain to be characterized. Here, we found that Siglec5 and Siglec14 recognize lipid compounds produced by Trichophyton, a fungal genus containing several pathogenic species. Biochemical approaches revealed that the Siglec ligands are fungal alkanes and triacylglycerols, an unexpected finding that prompted us to search for endogenous lipid ligands of Siglecs. Siglec5 weakly recognized several endogenous lipids, but the mitochondrial lipid cardiolipin and the anti-inflammatory lipid 5-palmitic acid-hydroxystearic acid exhibited potent ligand activity on Siglec5. Further, the hydrophobic stretch in the Siglec5 N terminus region was found to be required for efficient recognition of these lipids. Notably, this hydrophobic stretch was dispensable for recognition of sialic acid. Siglec5 inhibited cell activation upon ligand binding, and accordingly, the lipophilic ligands suppressed interleukin-8 (IL-8) production in Siglec5-expressing human monocytic cells. Siglec14 and Siglec5 have high sequence identity in the extracellular region, and Siglec14 also recognized the endogenous lipids. However, unlike Siglec5, Siglec14 transduces activating signals upon ligand recognition. Indeed, the endogenous lipids induced IL-8 production in Siglec14-expressing human monocytic cells. These results indicated that Siglec5 and Siglec14 can recognize lipophilic ligands that thereby modulate innate immune responses. To our knowledge, this is the first study reporting the binding of Siglecs to lipid ligands, expanding our understanding of the biological function and importance of Siglecs in the innate immunity.

Re-evaluation of mono- and di-glycerides of fatty acids (E 471) as food additives

The EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of mono- and di-glycerides of fatty acids (E 471) when used as a food additive. The Panel considered that it is very likely that hydrolysis of mono- and di-glycerides of fatty acids by lipases in the gastrointestinal tract would occur, resulting in the release of glycerol and fatty acids. Glycerol (E 422) and fatty acids (E 570) have been re-evaluated and the Panel concluded that there was no safety concern regarding their use as food additives. Toxicological studies with mono- and di-glycerides rich in unsaturated fatty acids were considered for the re-evaluation of E 471. No evidence for adverse effects was reported in short-term, subchronic studies, chronic, reproductive and developmental toxicity studies. Neither carcinogenic potential nor a promotion effect in initiation/promotion was reported. The available studies did not raise any concern with regard to genotoxicity. The refined estimates were based on 31 out of 84 food categories in which E 471 is authorised. The Panel noted that the contribution of E 471 represented at the mean only 0.8-3.5% of the recommended daily fat intake. Based on the approach described in the conceptual framework for the risk assessment of certain food additives re-evaluated under Commission Regulation (EU) No 257/2010 and taking into account the considerations mentioned above, the Panel concluded that there was no need for a numerical acceptable daily intake (ADI) and that the food additive mono- and di-glycerides of fatty acids (E 471) was of no safety concern at the reported uses and use levels. The Panel recommended some modifications of the EU specifications for E 471.

Combined chromatography and mass spectrometry for the molecular characterization of food emulsifiers

Food emulsifiers are widely used to stabilise water-fat emulsions such as mayonnaise and dressings. They are prepared by oligomerisation of a poly-alcohol (as e.g. glycerol or citric acid) followed by a reaction with fatty acids. In order to gain insight in the chemical composition of different emulsifiers, a range of chromatographic methods including gas chromatography, size exclusion chromatography, normal phase- and reversed phase liquid chromatography either or not in combination with mass spectrometry was deployed. The different methods turned out to be highly complementary. By combining the information from different methods the polar head group and the fatty acid part of the emulsifier can be characterised in detail. Mass spectrometry is indispensable for establishing the number of polar molecules in the head group as well as for establishing the correct combinations of fatty acids in one molecule. Ten commercial emulsifiers were described at the level of number and type of polar groups and fatty acids present.

The presence of carbon nanostructures in bakery products induces metabolic stress in human mesenchymal stem cells through CYP1A and p53 gene expression

Ingredients commonly present in processed foods are excellent substrates for chemical reactions during modern thermal cooking or processing, which could possibly result in deteriorative carbonization changes mediated by a variety of thermal reactions. Spontaneous self-assembling complexation or polymerization of partially combusted lipids, proteins, and other food macromolecules with synthetic food additives during high temperature food processing or baking (200-250 °C) would result in the formation of carbon nanostructures (CNs). These unknown nanostructures may produce adverse physiological effects or potential health risks. The present work aimed to identify and characterize the nanostructures from the crusts of bread. Furthermore, a toxicological risk assessment of these nanostructures was conducted using human mesenchymal stem cells (hMSCs) as a model for cellular uptake and metabolic oxidative stress, with special reference to induced adipogenesis. CNs isolated from bread crusts were characterized using transmission electron microscopy. The in vitro risk assessment of the CNs was carried out in hMSCs using an MTT assay, cell morphological assessment, a reactive oxygen species assay, a mitochondrial trans-membrane potential assay, cell cycle progression assessment and gene expression analysis. Our results revealed that bread crusts contain CNs, which may form during the bread-making process. The in vitro results indicate that carbon nanostructures have moderately toxic effects in the hMSCs at a high dose (400 μg/mL). The mitochondrial trans-membrane potentials and intracellular ROS levels of the hMSCs were altered at this dose. The levels of the mRNA transcripts of metabolic stress-responsive genes such as CAT, GSR, GSTA4, CYP1A and p53 were significantly altered in response to CNs.

Characterisation and oxidation stability of monoacylglycerols from partially hydrogenated corn oil

This study reported the characterisation of some types of monoacylglycerols (MAGs) obtained by the glycerolysis of different partially hydrogenated corn oils (PHCOs) catalysed by Al2O3 loaded with K2CO3 (K2CO3/Al2O3) under the previous selected conditions. A two-stage molecular distillation method of purifying the MAGs was introduced, and the obtained MAG products were more than 90.0 wt.% pure. The fatty acid composition of corn oil significantly changed after hydrogenation sequentially catalysed by Pricat™ Ni catalysts (9908 Ni/kieselguhr and 9920 Ni/Al2O3). The PHCO samples generated typical structures with β'-form crystals. Moreover, the melting regions of all hydrogenated samples and their MAGs shifted to higher temperatures. The oxidation stability of MAGs has been significantly increased using hydrogenation to change the fatty acid composition.

Study of different reaction schemes for the enzymatic synthesis of polyglycerol polyricinoleate

BACKGROUND

Different strategies for the solvent-free enzymatic production of polyglycerol polyricinoleate (PGPR) were explored in an attempt to simplify and improve the process. Besides the conventional procedure (obtaining polyricinoleic acid, followed by its esterification with polyglycerol), two alternative methods are proposed: (1) reversing the synthesis order, i.e. esterification of polyglycerol with ricinoleic acid and then the condensation of ricinoleic acid with the previously obtained polyglycerol ester; and (2) the enzymatic synthesis of PGPR in a single-step process.

RESULTS

The reaction sequences were carried out in an open-air reactor with free and immobilised lipases (triacylglycerol acylhydrolases, E.C. 3.1.1.3): Candida rugosa lipase to obtain polyricinoleic acid and Rhizopus oryzae lipase for the esterification of polyglycerol with the carboxyl group of ricinoleic or polyricinoleic acid. A co-immobilised derivative containing both lipases was used to catalyse the single-stage scheme. The three processes were carried out in a vacuum reactor, obtaining in every case PGPR that complied with the legal specifications of the European Community and recommendations provided in the Food Chemical Codex.

CONCLUSION

The results demonstrate that all three protocols are viable for the enzymatic synthesis of PGPR and require similar reaction times. The single-stage scheme is easier to carry out.

Development of a combined SEM and ICP-MS approach for the qualitative and quantitative analyses of metal nano and microparticles in food products [corrected]

An integrated approach based on the use of inductively coupled plasma mass spectrometry (ICP-MS) and scanning electron microscopy (SEM) for the qualitative and quantitative analyses of metal particles in foods was devised and validated. Different raw materials and food products, like wheat, durum wheat, wheat flour, semolina, cookies, and pasta were considered. Attention was paid to the development of sample treatment protocols for each type of sample to avoid potential artifacts such as aggregation or agglomeration. The analytical protocols developed followed by ICP-MS and SEM investigations allowed us the quantitative determination and the morphological and dimensional characterization of metal nano- and microparticles isolated from the raw materials and finished food products considered. The ICP-MS method was validated in terms of linearity (0.8-80 μg/g and 0.09-9 μg/g for Fe and Ti, respectively), quantification limits (0.73 μg/g for Fe and 0.09 μg/g for Ti), repeatability (relative standard deviation (RSD) % equal to 10% for Fe and 20% in a wheat matrix as an example), and extraction recoveries (93 ± 2-101 ± 2%). Validation of the scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) measurements was performed working in a dimensional range from 1 to 100 μm with an estimated error in the size determination equal to 0.5 μm. ICP-MS data as well as SEM measurements showed a decrease in the concentration of metal particles from wheat to flour and from durum wheat to semolina samples, thus indicating an external contamination of grains by metal particles. These findings were confirmed by environmental SEM analysis, which allowed investigation of particles of lower dimensions. Generally, the largest number of particles was found in the case of iron and titanium, whereas particles of copper and zinc were only occasionally found without any possibility of quantifying their number.

Synergistic effect of high and low molecular weight molecules in the foamability and foam stability of sparkling wines

The foam of sparkling wines is a key parameter of their quality. However, the compounds that are directly involved in foam formation and stabilization are not yet completely established. In this work, seven sparkling wines were produced in Bairrada appellation (Portugal) under different conditions and their foaming properties evaluated using a Mosalux-based device. Fractionation of the sparkling wines into four independent fractions, (1) high molecular weight material, with molecular weight higher than 12 kDa (HMW), (2) hydrophilic material with molecular weigh between 1 and 12 kDa (AqIMW), (3) hydrophobic material with molecular weigh between 1 and 12 kDa (MeIMW), and (4) hydrophobic material with a molecular weight lower than 1 kDa (MeLMW), allowed the observation that the wines presenting the lower foam stability were those that presented lower amounts of the MeLMW fraction. The fraction that presented the best foam stability was HMW. When HMW is combined with MeLMW fraction, the foam stability largely increased. This increase was even larger, approaching the foam stability of the sparkling wine, when HMW was combined with the less hydrophobic subfraction of MeLMW (fraction 3). Electrospray tandem mass spectrometry (ESI-MS/MS) of fraction 3 allowed the assignment of polyethylene glycol oligomers (n = 5-11) and diethylene glycol 8-hydroxytridecanoate glyceryl acetate. To observe if these molecules occur in sparkling wine foam, the MeLMW was recovered directly from the sparkling wine foam and was also analyzed by ESI-MS/MS. The presence of monoacylglycerols of palmitic and stearic acids, as well as four glycerylethylene glycol fatty acid derivatives, was observed. These surface active compounds are preferentially partitioned by the sparkling wine foam rather than the liquid phase, allowing the inference of their role as key components in the promotion and stabilization of sparkling wine foam.

Application of liquid chromatography in polymer non-ionic antistatic additives analysis

This article investigates the applicability of HPLC-UV, ultra performance LC-evaporative light-scattering detection (UPLC-ELSD), HPLC-ESI(+)-MS and HPLC-hybrid linear ion trap (LTQ) Orbitrap MS for the analysis of different non-ionic antistatic additives, Span 20, Span 60, Span 65, Span 80, Span 85 (sorbitan fatty acid esters), Atmer 129 (glycerol fatty acid ester) and Atmer 163 (ethoxylated alkylamine). Several alkyl chain length or different degrees of esterification of polyol derivatives can be present in commercial mixtures of these polymer additives. Therefore, their identification and quantification is complicated. Qualitative composition of the studied compounds was analysed by MS. HPLC-UV, UPLC-ELSD and HPLC-LTQ Orbitrap MS methods were applied to the quantitative determination of the different Spans, Atmer 129 and Atmer 163, respectively. Quality parameters of these methods were established and no derivatization was necessary.