Untargeted metabolomics reveals links between Tiger nut (Cyperus esculentus L.) and its geographical origin by metabolome changes associated with membrane lipids

Tiger nuts and tiger nut milk are well-known Valencian products, and step-by-step these tubers and the tuber-based beverage are becoming more and more relevant products in international markets. However, the increasing demand and success of Valencian tiger nuts did not allow protected designation of origin (PDO) tuber to supply the domestic and international markets. Therefore, the verification of the geographical origin is highly required. In this research, the main objective was to combine an advance analytical method and chemometrics tools in order to decipher the geographical origin of 45 tiger nut samples from (i) ‘Xufa de València’ PDO and (ii) African samples. The analytical method, based on solid-liquid extraction followed by ultra-high performance liquid chromatography coupled to high resolution tandem mass spectrometry (UHPLC-HRMS) metabolomics approach, highlighted sensitivity and wide linear dynamic range in order to simultaneously analyse polar and non-polar metabolites. After data processing, a pronounced sample clustering according to the geographical origin was clearly observed using unsupervised models, and supervised models revealed that tiger nuts lipidome was associated with the geographical origin. As a result, African samples highlighted an overexpression of phospholipids, such as phosphatidylethanolamine 34:1, and triacylgricerols crosslinked to environmental stress and alteration of membrane lipid compositions.     

A new method in designing compatibility and adhesion of EVA/PMMA blend by using EVA-<Emphasis Type="Italic">g</Emphasis>-PMMA with controlled graft chain length

Atom transfer free radical polymerization (ATRP) was employed in a synthesis of graft polymer EVA-g-PMMA with controlled length of side PMMA chains. Three steps of synthesis: partial hydrolysis of EVA, esterification with chloroacetyl chloride and ATRP grafting were performed to produce EVAOH, macroinitiator EVACl and grafted polymers G8020 (EVA/PMMA?=?80/20 wt%) and G6040 (EVA/PMMA?=?60/40 wt%). FTIR, Raman and NMR spectroscopy were used in the determination of the chemical structure and modification of EVA. Transmitted light and dark field microscopy showed higher affinity for coil formation of EVA-g-PMMA with longer PMMA side chains, i.e. G6040 compatibilizer. Morphological, thermal and adhesive properties of optical fiber adhesives of graft polymers and polymer blends poly(ethylene-co-vinyl acetate)-blend-poly(methyl methacrylate) (EVA/PMMA) compatibilized with 1 wt% of EVA-g-PMMA, were studied. Image analysis of SEM micrographs showed effective compatibilization with short grafted chains (G8020) that was indicated by lower porosity characteristics. TG/DTG analysis enabled determination of degree of hydrolysis and amount of chloro-functionalized groups. DSC analysis showed higher thermal stability of G8020 polymer. Single lap joint of adhesives/optical fibers were subjected to adhesive testing and obtained results for maximal force applied and adhesive failure suggested the visible influence of the length of graft chains on adhesion.     

A new approach to evaluating the toxicity and genotoxicity of disinfected drinking water

The aim of this study was to evaluate the formation of toxic and genotoxic compounds in surface drinking waters treated with two widely used disinfectants, sodium hypochlorite (NaClO) and chlorine dioxide (ClO(2)), and a new disinfectant, peracetic acid (PAA). For this purpose a pilot plant was set up to add these biocides continuously to pre-filtered lake water flowing into three different basins. During three seasonal experiments, short-term in vivo tests (with plant, fish and molluscs) and in vitro tests (with bacteria, yeast and human cells) were carried out to evaluate the formation of genotoxic disinfection by-products (DBPs). Gas chromatography/mass spectrometry (GC/MS) was used to identify DBPs produced during the different treatments, microbiological analyses were performed to test the biocidal activity of the disinfectants, and chemical analyses were carried out to evaluate the quality of the water. The pilot drinking water plant under study was useful in studying the toxicity and genotoxicity of disinfected drinking water with this combined chemical/biotoxicological approach. This paper describes the setting up of the pilot plant and sets out/reports the results of the microbiological and chemical analyses.     

Amperometric response from the glycolytic versus the pentose phosphate pathway in Saccharomyces cerevisiae cells

The two main metabolic pathways involved in sugar metabolism, i.e., the pentose phosphate pathway (PPP) and the glycolytic pathway (GP), were amperometrically monitored using a double-mediator system composed of menadione and ferricyanide. With the use of the Saccharomyces cerevisiae deletion mutant, EBY44, lacking the gene encoding for the branch point enzyme phosphoglucose isomerize, selective amperometric monitoring of the PPP, mainly producing NADPH, and the GP, mainly producing NADH, could be achieved. It was found that the bioelectrocatalytic current was primarily originating from NADPH. This conclusion was supported by metabolite flux analysis, confirming that, in the presence of menadione, the cells increase the rate of NADPH-producing reactions although these processes might be detrimental to cell survival. The higher rate of in vivo NADPH-dependent menadione reduction can be ascribed to the fact that the intracellular NADPH/NADP(+) ratio is much higher than NADH/NAD(+) as well as that the former ratio is more tightly controlled. This tight control over the cofactor ratios is lost upon cell disintegration as observed from spectrophotometric assays using crude cell extract, and amperometric investigations of permeabilized cells indicate a higher rate of NADH- than NADPH-dependent menadione reduction. These in vitro experiments show a higher activity of NADH-dependent than NADPH-dependent menadione-reducing dehydrogenases in S. cerevisiae cells.     

Kinetics of lipid oxidation in the presence of cinnamic acid derivatives

The effects of seven (prenyl‐ and methoxy‐) derivatives of cinnamic acid (0.1 mM) on the kinetics of lipid (sunflower oil triacylglycerols, TGSO) bulk phase oxidation at 80 °C have been compared. Synthesis of prenyl cinnamic acid derivatives: 3‐prenyl‐4‐hydroxy‐cinnamic acid (PHC), 3,5‐diprenyl‐4‐hydroxy‐cinnamic acid (DPHC), 2,2‐di‐methyl‐6‐carboxy‐ethenyl‐2H‐benzopyran (DMCB), 2,2‐dimethyl‐6‐carboxy‐ethenyl‐8‐prenyl‐2H‐benzopyran (DCEPB) present in Brazilian propolis has been performed. The monoprenyl derivative (PHC) has been found to exert a higher antioxidant activity as compared to the diprenyl derivative (DPHC). However, cinnamic acid derivatives DMCB and DCEPB have caused no change in the kinetics of TGSO oxidation. The results obtained have been compared with those on related compounds containing a cinnamic acid moiety as a structural feature, such as 4‐hydroxy‐cinnamic (p‐coumaric), 3‐methoxy‐4‐hydroxy‐cinnamic (ferulic) and 3,5‐dimethoxy‐4‐hydroxy‐cinnamic (sinapic) acids, as well as with data on butylated hydroxytoluene (BHT) and α‐tocopherol (αToc). PHC has shown a stronger antioxidant efficiency than BHT, p‐coumaric and ferulic acid, but a weaker antioxidant efficiency than α‐Toc and sinapic acid. The observed antioxidant effect of DPHC was stronger than that of p‐coumaric and ferulic acids and weaker than that of α‐Toc, BHT and sinapic acid.     

Nonthermal Technologies for Fruit and Vegetable Juices and Beverages: Overview and Advances

In recent years, there has been a growing interest in the design of novel nonthermal processing systems that minimally modify sensory, nutritional, and functional properties of fruit and vegetable juices and beverages. The benefits of nonthermal treatments are strongly dependent on the food matrix. Thus, an understanding of the effects that these technologies exert on the properties of juices and beverages is important to design and optimize technological parameters to produce value‐added products. This review covers research on nonthermal electrical treatments, high pressure processing, ultrasound, radiation processing, inert gas treatments, cold plasma, and membrane processing. Advances towards optimization of processing conditions, and combined technologies approaches have been also extensively reviewed. This information could be useful to: (1) manage processing systems and optimize resources; (2) preserve nutritional value and organoleptic properties, and (3) provide processing conditions for validation of these technologies at the industrial scale.     

Cyanobacteria,Cyanotoxins, and Neurodegenerative Diseases: Dangerous Liaisons

The prevalence of neurodegenerative disease (ND) is increasing, partly owing to extensions in lifespan, with a larger percentage of members living to an older age, but the ND aetiology and pathogenesis are not fully understood, and effective treatments are still lacking. Neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis are generally thought to progress as a consequence of genetic susceptibility and environmental influences. Up to now, several environmental triggers have been associated with NDs, and recent studies suggest that some cyanotoxins, produced by cyanobacteria and acting through a variety of molecular mechanisms, are highly neurotoxic, although their roles in neuropathy and particularly in NDs are still controversial. In this review, we summarize the most relevant and recent evidence that points at cyanotoxins as environmental triggers in NDs development.     

Description of the microflora of sourdoughs by culture-dependent and culture-independent methods

Four types of sourdoughs (L, C, B, Q) from artisanal bakeries in Northern Italy were studied using culture-dependent and culture-independent methods. In all samples, the yeast numbers ranged from 160 to 10⁷ cfu/g, and the numbers of lactic acid bacteria (LAB) ranged from 10³ to 10⁹ cfu/g. The isolated LAB were sequenced, and a similarity was noted between two samples (C, Q), both in terms of the species that were present and in terms of the percentage of isolates. In these two samples, Lactobacillus plantarum accounted for 73% and 89% of the bacteria, and Lactobacillus brevis represented 27% and 11%. In the third sample (B), however, the dominant LAB isolate was Lb. brevis (73%), while Lb. plantarum accounted for only 27%. The fourth sourdough (L) was completely different from the others. In this sample, the most prominent isolate was Weisella cibaria (56%), followed by Lb. plantarum (36%) and Pediococcus pentosaceus (8%). In three out of four samples (L, C and Q), all of the yeasts isolated were identified as Saccharomyces cerevisiae, yet only Candida humilis (90%) and Candida milleri (10%) were isolated in the fourth sample (B). The microbial ecology of the sourdoughs was also examined with direct methods. The results obtained by culture-independent methods and DGGE analysis underline a partial correspondence between the DNA and RNA analysis. These results demonstrate the importance of using a combined analytical approach to explore the microbial communities of sourdoughs.