A Non-Targeted High-Resolution Mass Spectrometry Study for Extra Virgin Olive Oil Adulteration with Soft Refined Oils: Preliminary Findings from Two Different Laboratories

This work presents a non-targeted high-resolution mass spectrometry inter-laboratory study for the detection of new chemical markers responsible of soft refined oils addition to extra virgin olive oils. Refined oils (soft deodorized and soft deacidified) were prepared on a laboratory scale starting from low-quality olive oils and analyzed together with a set of pure extra virgin olive oil (EVOO) samples and with mixtures of adulterated and pure EVOO at different percentages. The same analytical workflow was applied in two different laboratories equipped with two types of instrumentation (Q-Orbitrap and Q-TOF); a group of discriminant molecules was selected, and a tentative identification of compounds was also proposed. In summary, 12 molecules were identified as markers of this specific adulteration, and seven of them were selected as discriminative in both the laboratories, with a similar trend throughout the samples (i.e., propylene glycol 1 stearate). The results obtained in the two laboratories are comparable, concretely demonstrating the inter-laboratory repeatability of non-targeted studies. As a confirmation, the same markers were detected also in "in-house"mixtures and in suspect commercial deodorized mixtures, reinforcing the robustness of the results obtained and proving that, thanks to these molecules, mixtures containing at least 40% of adulterated oils can be detected

Metabolic fingerprinting strategy: Investigation of markers for the detection of extra virgin olive oil adulteration with soft-deodorized olive oils

As extra virgin olive oil (EVOO) is a high value commodity, it might be subject of various fraudulent practices. This study is focused on a challenging authentication issue, addition of lower grade, soft-deodorized olive oil to EVOO. In the first step, sample sets of authentic EVOOs, soft-deodorized oils and their admixtures were extracted by aqueous methanol; obtained polar fractions were then analysed by ultra-high performance liquid chromatography coupled to hybrid quadrupole time-of-flight high-resolution tandem mass spectrometry (UHPLC-QTOF-HRMS/MS). Subsequent chemometric evaluation of metabolic fingerprints enabled suggestion of several ions that might be characteristic for deodorized oils; most of tentatively identified compounds were oxidized fatty acid derivatives. In the second phase, the ‘marker' ions were employed for target analysis by ultra-high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS) what enabled achieving lower the detection limits. Two compounds were selected as the best markers for detection of soft-deodorized olive oil addition, tentatively identified as methyl ester of hydroxy octadecenoic acid and ester derivative of oleic acid

A novel approach based on untargeted lipidomics reveals differences in the lipid pattern among durum and common wheat

In the present work the possibility of using an untargeted metabolomic strategy to discriminate between common and durum wheat lipidome for an authenticity purpose was explored. A first study was conducted by analyzing 52 samples from two durum and common wheat varieties. Afterwards, an extended and independent sample set (173 samples and five varieties) was used as a confirmatory study to verify the stability and consistency of the models obtained. Putatively identified markers were evaluated applying ROC curves resulting in individual marker AUC >90% both in preliminary and confirmatory study. In addition, digalactosyl diglyceride (DGDG) 36:4 was shown to be an effective marker differentiating between authentic durum wheat and its adulterated admixture down to 3% adulteration level, which is the maximum contamination level allowed by Italian legislation. The results demonstrated that untargeted lipidomics, in conjunction with chemometric tools has a significant potential for screening and detection of wheat fraud

Adaptation of anammox bacteria to low temperature via gradual acclimation and cold shocks: Distinctions in protein expression, membrane composition and activities

Anammox bacteria enable efficient removal of nitrogen from sewage in processes involving partial nitritation and anammox (PN/A) or nitrification, partial denitrification, and anammox (N-PdN/A). In mild climates, anammox bacteria must be adapted to ≤15 °C, typically by gradual temperature decrease; however, this takes months or years. To reduce the time necessary for the adaptation, an unconventional method of ‘cold shocks’ is promising, involving hours-long exposure of anammox biomass to extremely low temperatures. We compared the efficacies of gradual temperature decrease and cold shocks to increase the metabolic activity of anammox (fed batch reactor, planktonic “Ca. Kuenenia”). We assessed the cold shock mechanism on the level of protein expression (quantitative shot-gun proteomics, LC–HRMS/MS) and the structure of membrane lipids (UPLC–HRMS/MS). The shocked culture was more active (0.66±0.06 vs 0.48±0.06 kg-N/kg-VSS/d) and maintained the relative content of N-respiration proteins at levels consistent levels with the initial state, whereas the content of these proteins decreased in gradually acclimated culture. Cold shocks also induced a more efficient expression of potential cold shock proteins (e.g. ppiD, UspA, pqqC), while putative cold shock proteins CspB and TypA were upregulated in both cultures. Ladderane lipids characteristic for anammox evolved to a similar end-point in both cultures; this confirms their role in anammox bacteria adaptation to cold and indicates a three-pronged adaptation mechanism (ladderane alkyl length, introduction of shorter non-ladderane alkyls, polar headgroup). Overall, we show the outstanding potential of cold shocks for low-temperature adaptation of anammox bacteria and provide yet unreported detailed mechanisms of anammox adaptation to low temperatures.BT/Environmental Biotechnolog