Uptake of the cyanobacterial toxin cylindrospermopsin in Brassica vegetables

Toxin-producing cyanobacterial species are increasingly being found in freshwater systems. However, literature on the impact of many cyanobacterial toxins on plants is scarce. Cylindrospermosin (CYN), a secondary metabolite of cyanobacteria such as Cylindrospermopsis and Aphanizomenon species, is a potent hepatotoxin and protein synthesis inhibitor. Worryingly, CYN is increasingly found in surface and drinking water worldwide causing human and animal intoxications. Further, exposure of crop plants to CYN by irrigation with contaminated water has already been shown. Therefore, in this study, horticulturally important and highly consumed Brassica species were investigated to determine the level of CYN in the leaves after exposure of the roots to the toxin. Treatment of Brassica oleracea var. sabellica, Brassica juncea, and Sinapis alba under varying experimental conditions showed significant CYN uptake, with CYN levels ranging from 10% to 21% in the leaves compared to the CYN concentration applied to the roots (18–35 μg/l). In seedlings, CYN concentrations of up to 49 μg/g fresh weight were observed. Thus, crop plants irrigated with CYN-containing water may represent a significant source of this toxin within the food chain.     

Quantification of the Alternaria mycotoxin tenuazonic acid in beer

Tenuazonic acid (TA) is a major water soluble Alternaria mycotoxin. In the present work, a method for the quantification of TA in beer by liquid chromatography–ion-trap multistage mass spectrometry after derivatization with 2,4-dinitrophenylhydrazine is described. The method is based on a rapid workup procedure and features a LOD of 2 μg/kg without preconcentration using 400 mg of sample. Validation was performed for a working range of 8–500 μg/kg.     

Oleuropein/ligstroside isomers and their derivatives in Portuguese olive mill wastewaters

Olive mill wastewaters (OMW) are a potential source of biophenols, but they have a complex composition with many unknown phenolics. The analysis of purified methanol extracts from two Portuguese OMW by electrospray mass spectrometry in the negative mode showed [M−H]⁻ ions at m/z 539 and m/z 523, corresponding respectively to oleuropein and ligstroside isomers which contain the glucose unit linked to its aromatic moiety. Also, the fragmentation pathway of the [M−H]⁻ ions at m/z 863, 685 and 847 indicated the presence of a diglucoside derivative of the oleuropein isomer and of mono- and diglucosides of the ligstroside isomer, respectively. Moreover, the two OMW samples contained an elenoic derivative of the ion at m/z 685 and a degradation product (m/z 453) of the [M−H]⁻ ion at m/z 523. Future studies focusing on the abundance of these compounds on OMW, as well as their bioactivities, will determine their possible industrial exploitation.     

The interactive effects of irrigation,nitrogen fertilisation rate,delayed harvest and storage on the polyphenol content in red grape (Vitis vinifera) berries: A factorial experimental design

Polyphenol concentrations, including anthocyanidins, flavonols, flavan-3-ols and stilbenes, were quantified by liquid chromatography/mass spectrometry in two cultivars of red grapes for daily consumption, which were subjected to different kinds of water supply and nitrogen fertilisation rates. Samples from the same vineyards were also analysed after a 6 week storage in a refrigerator and 6 week delayed harvesting. Berry skins and seeds were analysed separately.     

Tocols of selected spring wheat (Triticum aestivum L.), einkorn wheat (Triticum monococcum L.) and wild emmer (Triticum dicoccum Schuebl [Schrank]) varieties

Wheat contributes significantly worldwide to antioxidant income with beneficial healthy effects. Two varieties of einkorn wheat (Triticum monococcum L. – Escana and Schwedisches Einkorn), two varieties of wild emmer [Triticum dicoccum Schuebl (Schrank)] (Rudico and Kahler Emmer) and three varieties of spring wheat (Triticum aestivum L. – Granny, Kärtner Früher and SW Kadrilj) were evaluated for tocols – tocopherols and tocotrienols by high performance liquid chromatography – electrospray ionisation tandem mass spectrometry (HPLC–ESI/MS/MS). Investigated emmer and einkorn wheat varieties have shown minor lower total tocols content in comparison with spring varieties, however significant typical levels of tocopherols and tocotrienols were found in these groups. In einkorn wheat varieties the major abundance of total tocols is represented by tocotrienols (Schwedisches Einkorn 65.0%, Escana 54.9%), in emmer wheat varieties the abundance of tocotrienols and tocopherols were similar (Rudico 48.9% of tocotrienols, Kahler Emmer 47.6%), whereas in spring bread wheat higher tocopherols (SW Kadrilj 54.5%, Kärtner Früher 60.2%, Granny 55.0%) were recorded.     

An improved LC-MS/MS method for the quantitation of acrylamide in processed foods

An improved liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of acrylamide in processed foods. The homogenized samples, spiked with ¹³C₃-acrylamide as an internal standard, were extracted with water and centrifuged. D₅-3-chloropropanediol as a recovery standard was added to 1-ml aliquots, and the sample was purified with a C₁₈-cartridge column. The extract was directly analyzed using LC-MS/MS without derivatization. The ion transitions of 72–55 m/z (acrylamide), 75–58 m/z (¹³C₃-acrylamide), and 116–98 m/z (d₅-3-chloropropanediol) were found to be the most reliable for the identification and quantification of acrylamide in multiple reaction monitoring. The limit of quantification for acrylamide, defined as a signal-to-noise ratio of 10:1, was 2 μg/kg. The use of d₅-3-chloropropanediol minimized the effects of variation in the sample matrixes and increased the quality of analysis. This method could be applied to the quantification of acrylamide in processed foods.     

Modelling the formation of heterocyclic amines in slices of longissimus thoracis and semimembranosus beef muscles subjected to jets of hot air

The formation of heterocyclic amines (HAs) was modelled in slices of longissimus thoracis (LT) and semimembranosus (SM) beef muscles subjected to jets of hot air at temperatures ranging from 170 and 250 °C and treatment times ranging from 1 to 20 min. The quantity of HAs formed in the SM muscle was clearly less that that formed in the LT muscle as soon as the heat treatment was longer than 300 s. The extreme dehydration obtained with the hot-air jets slowed the formation of IQx, MeIQx and, particularly, 4,8-DiMeIQx compared with superheated steam treatments. The reverse effect was observed for PhIP concentrations which increased 1.4- to 5.5-fold. This highlights the important effect of water activity variations on HA formation, even at very low a_w values.     

Matrix effects on the bioavailability of resveratrol in humans

The pharmacokinetics of resveratrol in 11 healthy male volunteers has been assessed in a randomized, crossover, controlled clinical trial after the administration of three grape products: red wine (250 mL), grape juice (1/L), or tablets (red wine extracts enriched with trans-resveratrol). Doses of trans-resveratrol independently of the product administered, were about 14 μg/kg. Biological samples were collected and analysed by capillary gas chromatography–mass spectrometry. cis-Resveratrol, trans-resveratrol and dihydroresveratrol were determined in plasma and urine. Plasma concentration of trans-resveratrol after hydrolysis increased as a response to all grape products and that of cis-resveratrol after wine and grape juice. Free forms of these phenolic compounds were deemed undetectable in plasma. Despite similar trans-resveratrol doses being administered, its bioavailability from wine and grape juice was 6-fold higher, than that from tablets. Resveratrol was better absorbed from natural grape products than from tablets, pointing out the importance of the matrix in its bioavailability.     

Comparison of methods for the microbiological identification and typing of Cronobacter species in infant formula

Cronobacter species represent an emerging opportunistic foodborne pathogen associated with meningitis and necrotizing enterocolitis in infants. Current evidence indicates that powdered infant formula (PIF) is the main source of Cronobacter contamination. A total of 75 strains of Cronobacter spp. from different geographic regions, as well as from PIF processing environments, were identified and typed with different methods, including biochemical profiling by the API 20E system (bioMérieux, Marcy l’Etoile, France), protein profiling by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and genotypic profiling by ribotype. Analysis by MALDI-TOF MS and biochemical identification was more accurate compared with ribotype analysis. However, MALDI-TOF MS typing and ribotype analysis showed more discriminatory ability compared with biochemical phenotyping. In conclusion, MALDI-TOF MS is a rapid and reliable tool to identify Cronobacter spp. in PIF and has the potential to trace dissemination of Chronobacter along the production chain.     

Anthocyanins composition and antioxidant activity of two major wild Nitraria tangutorun Bobr. variations from Qinghai-Tibet Plateau

Nitraria tangutorun Bobr., a unique kind of fruit, widely spreads in the Qinghai-Tibet Plateau. In the present study, nine anthocyanins were identified in two variations (purple fruit and red fruit) of N. tangutorun by HPLC/DAD-ESI/MS. Cyanidin-3-O-(trans-p-coumaroyl)-diglucoside (215.76 ± 22.91 mg of Mv3G5G equivalent per 100 g of fresh weight) and pelargonidin-3-O-(p-coumaroyl)-diglucoside (5.13 ± 0.35 mg of Mv3G5G equivalent per 100 g of fresh weight) were the main anthocyanins in the purple and red fruits respectively. In addition, most of the anthocyanins were acylated by coumaric acid, and the rare anthocyanins that naturally presented a coumaric acid in both cis and trans configurations have been detected. Furthermore, the extract of the two variations showed significantly different antioxidant activity (p < 0.01) according to DPPH, ABTS and FRAP assay. Purple fruit possessed higher antioxidant activity than red fruit. There were significant correlations between antioxidant activity and both the total polyphenol content and anthocyanins content. This work is valuable for elucidation of anthocyanins composition in N. tangutorun and for further utilization as a functional food and medicine material.     

Effect of lipid oxidation products on the formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in model systems

Ternary mixtures of creatinine, phenylalanine and lipids (or carbohydrates) were heated at 200 °C for 1 h to determine the potential contribution of lipids to the formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Although unoxidised lipids did not contribute to PhIP formation, their oxidation produced many compounds that significantly increased the formation of PhIP. Among the different lipid oxidation products (LOPs) studied, which included ω-6 and ω-3 derived lipid hydroperoxides, 2,4-alkadienals, 2-alkenals, 4,5-epoxy-2-alkenals, 4-oxo-2-alkenals, and 4-hydroxy-2-nonenal, 4-oxo-2-nonenal was the most reactive compound. It produced 32.48 pmol of PhIP/μmol of creatinine in comparison with the 7.92 pmol of PhIP/μmol of creatinine produced by the control phenylalanine/creatinine reaction mixture. 4-Oxo-2-nonenal reactivity was similar to that of most carbohydrates; although ribose and arabinose produced more PhIP (44–46 pmol of PhIP/μmol of creatinine). In addition to single LOP, the addition of oxidised soybean oil for 24–144 h at 60 °C also increased PhIP formation. All these results pointed out to a potential contribution of LOP to the formation of PhIP in food products. This contribution will depend on the lipid content of the food product and its easiness to be oxidised.     

Accumulation and species distribution of selenium in Se-enriched bacterial cells of the Bifidobacterium animalis 01

Bifidobacterium animalis 01 (B. animalis 01) could absorb 16.7–39.6% of inorganic selenium in the medium and transform most of it into organic selenium. Most of the organic selenium (50.7–63.0%) was found in the protein fraction, 9.62–18.7% in the polysaccharide fraction, 0.273–0.754% in the nucleic acid fraction, and 20.8–30.9% in other components. Furthermore, the selenium content of different protein extractions was in the following order: Alkaline-soluble protein-bound Se (46.5–53.4%) > Water-soluble protein-bound Se (27.4–30.8%) > Salt-soluble protein-bound Se (7.79–11.9%) > Alcohol-soluble protein-bound Se (not detected). Additionally, the molecular mass of most proteins or protein subunits containing selenium was about 10–20 kDa. Analysis by LC–MS showed that selenomethionine (SeMet) is the major selenocompound in protein.     

Prevalence and stability of lysozyme in cheese

The use of the preservative and potential allergen hen egg white lysozyme in cheese production has to be declared. In the present study, an HPLC method with fluorescence detection (HPLC-FLD) was optimised and validated for the analysis of lysozyme in cheese. Lysozyme was detected in concentrations between 30.8 and 386.2 mg/kg cheese in 30 out of 46 analysed commercial cheese samples. During cheese production and storage for 0–54 weeks a lysozyme satellite peak (LSP) was detected, which totals up to 18% of the lysozyme content. Mass spectrometry and peptide mass fingerprint revealed that LSP possesses the same primary structure as lysozyme. Since disulphide scrambling could not be detected, LSP was assigned to a conformational isomer of lysozyme. As a consequence, LSP was included in the HPLC-FLD analysis of lysozymes in cheese.     

Mycosporine-like amino acid composition of the edible red alga, Palmaria palmata (dulse) harvested from the west and east coasts of Grand Manan Island,New Brunswick

The oxygen radical absorbance capacity (ORAC), antiproliferative activities and mycosporine-like amino acid (MAA) profiles of methanol extracts from two grades of dulse harvested from locations varying in UV-exposure (west vs east coasts of Grand Manan Island, NB) were determined in the present study. MAAs confirmed by LC/MS in both grades 1 (low-UV) and 2 (high-UV) dulse were palythine, shinorine, asterina-330, palythinol and porphyra-334; usujirene was present only in grade 2 dulse. ORAC values of grade 1 and 2 dulse extracts were 36.42 and 38.78 μmol Trolox/g extract. B16-F1 murine skin melanoma cell proliferation was inhibited (p < .05) by 68.5% and 91.9% by grade 1 and 2 dulse extracts at 6.0 mg/mL. The antiproliferative efficacy of grade 2 dulse was greater (p < .05) than grade 1 from 0.375 to 6.0 mg/mL. MAA differences between the grade 1 and 2 dulse extracts likely influenced the antiproliferative efficacies, despite the similar ORAC values.     

Direct nanoHPLC-ESI-QTOF MS/MS analysis of tryptic caseinophosphopeptides

Caseinophosphopeptides (CPPs) were generated following tryptic hydrolysis of sodium caseinate. Hydrolysate peptides were separated and identified using nano-HPLC ESI-QTOF MS/MS. Sequence coverage in the 3 h hydrolysate was 79.4%, 55.6%, 80.9% and 68.1% for α_s1-, α_s2-, β- and κ-casein (CN), respectively. Variable levels of serine phosphorylation in β-CN f1–25 were observed in the 3 h hydrolysate. Analysis of β-CN f1–25 4P demonstrated that this peptide was stable during the course of hydrolysis. The effect of heat treatment (75 °C, 45 min) at pH 6.0, 7.0 and 8.0 on the peptide profile of the 3 h hydrolysate was studied. Compared to pH 6.0 and 8.0, least modification in phosphopeptide profiles was observed for the hydrolysate sample heated at pH 7.0. Different dephosphorylation and oxidation patterns were also observed following heat treatment at the three pH values. These results demonstrate that heat treatment, in addition to pH, has a major effect on both the phosphorylated and non-phosphorylated peptide profiles of CN hydrolysates.     

A review of botanical characteristics, phytochemistry, clinical relevance in efficacy and safety of Lycium barbarum fruit (Goji)

Lycium barbarum has been used as a traditional Chinese medicine (TCM) to nourish liver and kidney, and brighten the eye. The fruits are dried or freshly squeezed for their juice and concentrated for beverages. Among various constituents, a group of polysaccharides (LBP) with a Glycan-O-Ser glycopeptide structure has been most researched and considered to be important for the efficacy of L. barbarum. Studies indicate effects of L. barbarum on aging, neuroprotection, general well-being, fatigue/endurance, metabolism/energy expenditure, glucose control in diabetics, glaucoma, anti-oxidant properties, immunomodulation, anti-tumor activity and cytoprotection. In addition to TCM, L. barbarum can be sold as a dietary supplement or classified as a food based upon the long and safe traditional usage. This review is to provide background and updated information of chemical constituents and efficacies with safety including a new direction for research and current regulatory situation of L. barbarum.     

Isolation and evaluation of the antioxidant activity of phenolic constituents of the Garcinia brasiliensis epicarp

A new glycosylated biflavonone, morelloflavone-4′″-O-β-d-glycosyl, and the known compounds 1,3,6,7-tetrahydroxyxanthone, morelloflavone (fukugetin) and morelloflavone-7″-O-β-d-glycosyl (fukugeside) were isolated from the epicarp of Garcinia brasiliensis collected in Brazil. The structures of these compounds were established using ¹H and ¹³C NMR, COSY, gHMQC and gHMBC spectroscopy. The compounds exhibited antioxidant activity. The greatest potency was displayed by morelloflavone (2), with IC₅₀ = 49.5 mM against DPPH and absorbance of 0.583 at 400 μg/mL for the reduction of Fe³⁺. The weakest potency was displayed by 1,3,6,7-tetrahydroxyxanthone (1), with IC₅₀ = 148 mM against DPPH and absorbance of 0.194 at 400 μg/mL for the reduction of Fe³⁺.     

Dose-effect study on the antioxidant properties of leaves and outer bracts of extracts obtained from Violetto di Toscana artichoke

Artichoke (Cynara scolymus L.) is an edible vegetable largely used in the Mediterranean diet and in folk medicine. The present paper discusses the analysis of the polyphenol content of leaves and outer bracts of Violetto di Toscana artichoke using different extraction procedures with the aim of establishing a correlation between polyphenol subclasses and antioxidant activity measured on human LDL oxidized by copper ions. HPLC/DAD and HPLC/MS analyses revealed that both the matrixes contain identical polyphenol subclasses, with mainly quantitative differences. The antioxidant effect of four artichoke extracts decreases in the following order when the sum of total phenolic compounds was considered: ethanolic extract from leaves (IC₅₀ = 2.92 ± 0.46 μM); ethanolic extract from outer bracts (IC₅₀ = 4.04 ± 0.21 μM); ethyl acetate extract from leaves (IC₅₀ = 4.91 ± 0.11 μM); ethyl acetate extract from outer bracts (IC₅₀ = 10.18 ± 1.6 μM). IC₅₀ were also calculated considering the concentrations of single polyphenol subclasses. In both cases, the potency of antioxidant properties was not related to the amount of total polyphenols or the single subclasses.     

Evidence for galloylated type-A procyanidins in grape seeds

In this work, procyanidins were extracted with methanol from the seeds of white and red grape varieties, and fractionated using graded methanol/chloroform precipitation in order to obtain the oligomers of lower molecular weight. These were analyzed by electrospray ionization-mass spectrometry (ESI-MS and ESI-MS/MS) in the positive mode. Protonated molecules, [M+H]⁺, of procyanidin species of nongalloylated and monogalloylated type-A and type-B oligomers, with degree of polymerisation 2–5, and digalloylated oligomers, with degree of polymerisation 2–3, were observed in the ESI-MS spectra. Type-A procyanidin abundance accounted for 60–80% of the abundance of the corresponding type-B species. Independent of the interflavanic linkage, the abundance of monogalloylated dimers accounted for 20% of the abundance of the corresponding nongalloylated ones. For the higher degrees of polymerisation, the abundance of galloylated oligomers was shown to reach up to 60% of the abundance of the corresponding nongalloylated oligomers. Thiolytic analyses showed that the type-A interflavanic linkages were present in the terminal units whereas the type-B interflavanic linkages were present as extension units. Although many reports are already available regarding the analyses of procyanidin polymers and grape seed procyanidins, this is the first report for the occurrence of type-A galloylated procyanidins. The similarity of the relative abundances and structural features observed in the samples of both white and red grape varieties, shows that these are characteristic of grape seeds.