Investigation of the effect of refining on the presence of targeted mineral oil aromatic hydrocarbons in coconut oil

Impact of deodorisation time and temperature on the removal of different MOAH structures: a lab-scale study on spiked coconut oil

Vegetable fats and oils are prone to contamination by mineral oil hydrocarbons due to the lipophilic and ubiquitous character of the latter. As the aromatic fraction of these hydrocarbons, MOAH, is associated with carcinogenicity, mutagenicity, and detrimental effects on foetal development, finding strategies to limit or reduce their contamination is highly relevant. Deodorisation (i.e. a refining step) has shown the ability to remove MOAH < C25 in vegetable fats and oils, but there is little information about the structures removed. Therefore, the present study investigated the impact of deodorisation conditions on the removal of different structures of MOAH in spiked coconut oil. An inscribed central composite design was built with time and temperature as variables (0.5-4h, 150-240 °C), while pressure (3 mbar) and steam flow (1 g water/g oil per hour) were kept constant. The analysis of MOAH in the oil was performed using a fully automated liquid chromatography coupled with two parallel comprehensive two-dimensional gas chromatography systems with flame ionisation and time-of-flight mass spectrometric detection. Response surfaces plotting the MOAH loss according to time and temperature were built for different MOAH fractions. The latter were defined based on the number of aromatic rings (>3 or ≤3) and the number of carbon atoms present (C16-C20, C20-C24, C24-C35, C35-C40). It was found that at 200 °C, compounds < C24, including weakly alkylated triaromatics, could be reduced to below the limit of quantification, while at 230 °C, it was possible to remove >60% of the C24-C35 fraction, including pentaromatics of low alkylation.

Combined transcriptome and metabolome analysis of sugar and fatty acid of aromatic coconut and non-aromatic coconut in China

Sugar and fatty acid content are among the important factors that contribute to the intensity of flavor in aromatic coconut. Gaining a comprehensive understanding of the sugar and fatty acid metabolites in the flesh of aromatic coconuts, along with identifying the key synthetic genes, is of significant importance for improving the development of desirable character traits in these coconuts. However, the related conjoint analysis of metabolic targets and molecular synthesis mechanisms has not been carried out in aromatic coconut until now. UPLC-MS/MS combined with RNA-Seq were performed in aromatic coconut (AC) and non-aromatic coconut (NAC) meat at 7, 9 and 11 months. The results showed that D-fructose in AC coconut meat was 3.48, 2.56 and 3.45 fold higher than that in NAC coconut meat. Similarly, D-glucose in AC coconut meat was 2.48, 2.25 and 3.91 fold higher than that in NAC coconut meat. The NAC coconut meat showed a 1.22-fold rise in the content of lauric acid compared to the AC coconut meat when it reached 11 months of age. Myristic acid content in NAC coconut meat was 1.47, 1.44 and 1.13 fold higher than that in AC coconut meat. The palmitic acid content in NAC coconut meat was 1.62 and 1.34 fold higher than that in AC coconut meat. The genes SPS, GAE, GALE, GLCAK, UGE, UGDH, FBP, GMLS, PFK, GPI, RHM, ACC, FabF, FatA, FabG, and FabI exhibited a negative correlation with D-fructose (r = -0.81) and D-glucose (r = -0.99) contents, while showing a positive correlation (r = 0.85-0.96) with lauric acid and myristic acid. Furthermore, GALE, GLCAK, FBP, GMLS, and ACC displayed a positive correlation (r = 0.83-0.94) with palmitic acid content. The sugar/organic acid ratio exhibited a positive correlation with SPS, GAE, UGE, FabF, FabZ and FabI.

Investigation of potential migratables from paper and board food contact materials

Since the ban on single-use plastic articles in Europe, the food contact material (FCM) industry has been forced to move to more sustainable alternatives. Paper and board FCM are convenient alternatives but must be safe for consumers. This study aims to investigate potential migrations of various substances (e.g., plasticizers, photoinitiators, primary aromatic amines, mineral oil, and bisphenols) from straws and takeaway articles made of paper and board. Twenty straws and fifty-eight takeaway articles were carefully selected and investigated using liquid and gas chromatography coupled with tandem mass spectrometry or flame ionization detector. Fourteen substances of all the targeted categories were found in takeaway articles, including seven plasticizers, two photoinitiators, one primary aromatic amine, two bisphenols, and the saturated and aromatic fraction of mineral oil (MOSH and MOAH, respectively). In straws, fewer substances were detected, i.e., six substances, including three plasticizers, one photoinitiator, MOSH, and MOAH. At least one of the target substances was detected in 88% of the samples, demonstrating the importance of further evaluation of these materials. Finally, the associated risks were assessed, highlighting the potential risks for several types of articles regarding bisphenol A, one primary aromatic amine (3.3-DMB), and MOSH and MOAH.

The role of comprehensive two-dimensional gas chromatography in mineral oil determination

Mineral oil hydrocarbons (MOH) contain a wide structural diversity of molecules, for which the reference method of analysis is the online coupled liquid chromatography-gas chromatography with flame ionization detection (LC-GC-FID). These compounds are very heterogeneous from a toxicological viewpoint, and an accurate risk assessment when dealing with a MOH contamination can only be performed if sufficient information is available on the types of structures present (i.e., number of carbons, degree of alkylation, number of aromatic rings). Unfortunately, the separation performances of the current LC-GC-FID method are insufficient for such characterization, not even mentioning the possible coelution of interfering compounds which additionally hinder MOH determination. Comprehensive two-dimensional gas chromatography (GC × GC), while mostly used for confirmation purposes in the past, starts to prove its relevance for overcoming the weaknesses of the LC-GC method and reaching even better the analytical requirements defined in the latest EFSA opinion. The present paper therefore aims at highlighting how GC × GC has contributed to the understanding of the MOH topic, how it has developed to meet the requirements of MOH determination, and how it could play a role in the field for overcoming many of the current analytical and toxicological challenges related to the topic.