Martina Cirlini

Masked mycotoxins are efficiently hydrolyzed by human colonic microbiota releasing their aglycones.

Fusarium mycotoxins are secondary metabolites produced by Fusarium spp. in cereals. Among them, deoxynivalenol (DON) and zearalenone (ZEN) are widespread worldwide contaminants of cereal commodities and are ranked as the most important chronic dietary risk factors. Their conjugates, known as masked mycotoxins, have been described but are still not accounted for in risk assessment studies. This study demonstrates for the first time that DON and ZEN are effectively deconjugated by the human colonic microbiota, releasing their toxic aglycones and generating yet unidentified catabolites. For this reason, masked mycotoxins should be considered when evaluating population exposure.

Effects of orally administered fumonisin B1 (FB1), partially hydrolysed FB1, hydrolysed FB1 and N-(1-deoxy-D-fructos-1-yl) FB1 on the sphingolipid metabolism in rats

Fumonisin B1 (FB1) is a Fusarium mycotoxin frequently occurring in maize-based food and feed. Alkaline processing like nixtamalisation of maize generates partially and fully hydrolysed FB1 (pHFB1 and HFB1) and thermal treatment in the presence of reducing sugars leads to formation of N-(1-deoxy-D-fructos-1-yl) fumonisin B1 (NDF). The toxicity of these metabolites, in particular their effect on the sphingolipid metabolism, is either unknown or discussed controversially. We produced high purity FB1, pHFB1a+b, HFB1 and NDF and fed them to male Sprague Dawley rats for three weeks. Once a week, urine and faeces samples were collected over 24 h and analysed for fumonisin metabolites as well as for the sphinganine (Sa) to sphingosine (So) ratio by validated LC-MS/MS based methods. While the latter was significantly increased in the FB1 positive control group, the Sa/So ratios of the partially and fully hydrolysed fumonisins were indifferent from the negative control group. Although NDF was partly cleaved during digestion, the liberated amounts of FB1 did not raise the Sa/So ratio. These results show that the investigated alkaline and thermal processing products of FB1 were, at the tested concentrations, non-toxic for rats, and suggest that according food processing can reduce fumonisin toxicity for humans.

Masked fumonisins in processed food: co-occurrence of hidden and bound forms and their stability under digestive conditions

Fumonisins can occur in foodstuffs as free forms (prent, partially hydrolysed, or totally hydrolysed), as covalently bound fumonisins (bound fumonisins) and as non-covalently bound fumonisins (hidden fumonisins). The formation of several covalently bound fumonisin B1 conjugates upon reaction with sugars and/or amino acids has been reported in the literature so far, but occurrence data are still very poor. Since very little is known about the relevance of both hidden and bound fumonisins in processed products, the present study aimed to evaluate the occurrence of both masked forms in maize-based food products and to study their stability under digestive conditions. The behaviour of covalently bound fumonisin B1 conjugates upon in vitro digestion was evaluated, demonstrating their stability under these conditions. In addition, the co-occurrence of hidden and bound fumonisins in maize-based food products was investigated by application of both alkaline hydrolysis and simulated in vitro digestion assay. The e...

Concentration of DL-PCBs in fish from market of Parma city (north Italy): estimated human intake.

The concentrations of 12 congeners of non-ortho and mono-ortho dioxin-like polychlorinated biphenyls (ΣDL-PCB) were measured in 30 fish samples from Parma markets by GC/MS technique. The samples were randomly purchased, choosing the species commonly found in supermarkets. The concentration of DL-PCBs estimated remained under the fixed Italian limit of 4 pg g(-1)ww WHO-TEQ (World Health Organization-Toxic Equivalent) in the major part of the samples, so the situation seems to be not at a level sufficient to pose a risk to human health of the Parma population. The medium daily intake for DL-PCBs for Italian consumers (Parma) was also estimated. This value generally resulted minor than 2 pg g(-1) ww WHO-TEQ kg(-1) body weight, exceeding only in four cases: eel, smooth hound, starry smooth hound and tuna.

1H NMR study of fermented cocoa (Theobroma cacao L.) beans.

This study reports for the first time the metabolic profile of cocoa (Theobroma cacao L.) beans using the (1)H NMR technique applied to polar extracts of fermented cocoa beans. The simultaneous detection and quantification of amino acids, polyalcohols, organic acids, sugars, methylxanthines, catechins, and phenols were obtained by assigning the major signals of the spectra for different varieties of cocoa beans (Forastero, Criollo, and Trinitario) from different countries (Ecuador, Ghana, Grenada, and Trinidad). The data set obtained, representative of all classes of soluble compounds of cocoa, was useful to characterize the fermented cocoa beans as a function of the variety and geographic origin.

Volatile fingerprinting of chestnut flours from traditional Emilia Romagna (Italy) cultivars

The volatile profile of nine monocultivar chestnut flours, obtained from fruits grown in Italy (Parma province), was characterised by a head-space solid-phase microextraction (HS-SPME) coupled with GC-MS technique. The volatile fraction was composed of 44 main compounds belonging to different classes, mainly aldehydes, ketones, alcohols, furans and terpenes. Aldehydes, in particular hexanal, are the most abundant components. In order to better understand the origin of the different volatile compounds during the drying and milling processes, samples of fresh fruit were also analysed by the same technique and the data obtained were statistically and critically compared in order to get a picture of the volatile evolution in chestnut from fresh fruit to flour. Finally, the nine monocultivar flours were chemometrically classified on the basis of the main odour descriptors associated with the volatile fingerprinting.

LDS1-produced oxylipins are negative regulators of growth, conidiation and fumonisin synthesis in the fungal maize pathogen Fusarium verticillioides

Oxylipins are fatty acid-derived signaling compounds produced by all eukaryotes so far investigated; in mycotoxigenic fungi, they modulate toxin production and interactions with the host plants. Among the many enzymes responsible for oxylipin generation, Linoleate Diol Synthase 1 (LDS1) produces mainly 8-hydroperoxyoctadecenoic acid and subsequently different di-hydroxyoctadecenoic acids. In this study, we inactivated a copy of the putative LDS1 ortholog (acc. N. FVEG_09294.3) of Fusarium verticillioides, with the aim to investigate its influence on the oxylipin profile of the fungus, on its development, secondary metabolism and virulence. LC-MS/MS oxylipin profiling carried out on the selected mutant strain revealed significant quali-quantitative differences for several oxylipins when compared to the WT strain. The Fvlds1-deleted mutant grew better, produced more conidia, synthesized more fumonisins and infected maize cobs faster than the WT strain. We hypothesize that oxylipins may act as regulators of gene expression in the toxigenic plant pathogen F. verticillioides, in turn causing notable changes in its phenotype. These changes could relate to the ability of oxylipins to re-shape the transcriptional profile of F. verticillioides by inducing chromatin modifications and exerting a direct control on the transcription of secondary metabolism in fungi.

Brand-dependent volatile fingerprinting of Italian wines from Valpolicella

Head-space solid-phase microextraction (HS-SPME) coupled to gas-chromatography-mass spectrometry was developed and applied to obtain the volatile aromatic fingerprints of three typical Italian wines, Valpolicella, Amarone and Recioto, all produced in the restricted geographical area of Valpolicella (Veneto, Italy) with the same grape cultivars within the regulations of a rigid disciplinary of production. Differences between the three typologies are mainly linked to the different withering times to which grapes are subjected before vinification, which strongly influences the concentration and the development of volatile aroma compounds. A total of 22 different wines (7 Valpolicella, 10 Amarone and 5 Recioto) were characterised in terms of aromatic volatile profile with the aim to distinguish the different products and to evaluate the possibility to differentiate the same product from different brands. For the chemometric evaluation of the data one-way analysis of variance (ANOVA), principal component analysis (PCA) and hierarchical cluster analysis (HCA) were tested. All the chemometric tools employed allow to differentiate between the three products. More intriguing is the ability of the chemometric approach to differentiate between the same product (Amarone, Recioto) from different winery, thus showing the potential of this approach to characterize the brand-dependent typicality of wines, which is usually related to subtle technological differences which nevertheless have strong influences on the organoleptic characteristics of the products.

1H NMR Fingerprinting of Soybean Extracts, with Emphasis on Identification and Quantification of Isoflavones

1H NMR spectra were recorded of methanolic extracts of seven soybean varieties (Glycine max.), cultivated using traditional and organic farming techniques. It was possible to identify signals belonging to the groups of amino acids, carbohydrates, organic acids and aromatic substances in the spectra. In the aromatic zone, the isoflavone signals were of particular interest: genistein, daidzein, genistin, daidzin, malonylgenistin, acetylgenistin, malonyldaidzin signals were assigned and these compounds were quantified, resulting in accordance with published data, and further demonstrating the potential of the NMR technique in food science.

Deoxynivalenol & Deoxynivalenol-3-Glucoside Mitigation through Bakery Production Strategies: Effective Experimental Design within Industrial Rusk-Making Technology.

In the scientific field, there is a progressive awareness about the potential implications of food processing on mycotoxins especially concerning thermal treatments. High temperatures may cause, in fact, transformation or degradation of these compounds. This work is aimed to study the fate of mycotoxins during bakery processing, focusing on deoxynivalenol (DON) and deoxynivalenol-3-glucoside (DON3Glc), along the chain of industrial rusk production. Starting from naturally contaminated bran, we studied how concentrations of DON and DON3Glc are influenced by modifying ingredients and operative conditions. The experiments were performed using statistical Design of Experiment (DoE) schemes to synergistically explore the relationship between mycotoxin reduction and the indicated processing transformation parameters. All samples collected during pilot plant experiments were analyzed with an LC-MS/MS multimycotoxin method. The obtained model shows a good fitting, giving back relevant information in terms of optimization of the industrial production process, in particular suggesting that time and temperature in baking and toasting steps are highly relevant for minimizing mycotoxin level in rusks. A reduction up to 30% for DON and DON3Glc content in the finished product was observed within an acceptable technological range.