Investigation of urinary steroid metabolites in calf urine after oral and intramuscular administration of DHEA

DHEA (3 beta-hydroxy-androst-5-en-17-one) is a natural steroid prohormone. Despite a lack of information on the effect, DHEA and other prohormones are frequently used as a food supplement by body-builders. DHEA is suspected for growth promoting abuse in cattle as well. Considering the latter, urine samples from a previous exposure study in which calves were exposed to 1 g DHEA per day for 7 days, were used. The calves were divided in three groups: one orally treated, one intramuscularly injected, and a control group. The effect of this treatment on the urinary profile of several precursors and metabolites of DHEA was investigated. Urine samples were collected several days before and during the 7 days of administration and were submitted to a clean-up procedure consisting of a separation of the different conjugates (free, glucuronidated, and sulfated forms) of each compound on a SAX column (Varian). An LC-MS/MS method was developed for the detection and quantification of several metabolites of the pathway of DHEA including 17 alpha- and 17 beta-testosterone, 4-androstenedione, 5-androstenediol, pregnenolone, and hydroxypregnenolone. Elevated levels of DHEA, 5-androstenediol, and 17 alpha-testosterone were observed in the free and sulfated fraction of the urine of the treated calves, thus indicating that the administered DHEA is metabolized mainly by the a dagger(5)-pathway with 5-androstenediol as the intermediate. Sulfoconjugates of DHEA and its metabolites were found to constitute the largest proportion of the urinary metabolites. The free form was also present, but in a lesser extent than the sulfated form, while glucuronides were negligible

Impact of additives to lower the formation of acrylamide in a potato model system through pH reduction and other mechanisms

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Impact of chemical pre-treatments on the acrylamide formation and sensorial quality of potato crisps

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Comparison of potato varieties between seasons and their potential for acrylamide formation

BACKGROUND: Acrylamide is a probable human carcinogen produced during food preparation, including frying of potato products. The aim of this study was to investigate the impact of seasonal variation on tuber composition and its acrylamide generation potential. RESULTS: The chemical composition of potato varieties used respectively for French fry (Bintje and Ramos) and crisp (Lady Rosetta and Saturna) production was studied throughout a storage period of 9 months during two growing seasons (2003 and 2004), in addition to their acrylamide generation potential during preparation of French fries. A significant impact of variable climatological conditions on the reducing sugar, dry matter, total free amino acid and free asparagine contents of tubers was observed. Exceptionally warm summers gave rise to a lower reducing sugar content (expressed on a dry matter basis) and thus a lower susceptibility to acrylamide generation during frying. CONCLUSION: It cannot be excluded that potato growers and the potato-processing industry are confronted with some harvests that are more prone to acrylamide generation than others owing to climatological variability, thus confirming the importance of a multifactorial approach to mitigate acrylamide generation in potato products.</p

New insights into electrospray ionization of patulin

Patulin is a mycotoxin produced by several fungal species, mainly by Penicillium spp. and Aspergillus spp. Since patulin-producing fungi are widely spread, this toxin has been detected in food (fruit- and vegetable-based products, cereal products, cheese), feed and even in mouldy water-damaged dwellings. Co-occurrence of patulin with other mycotoxins has also been reported [1]. Patulin is commonly analyzed by liquid chromatography with UV detection. Liquid chromatography coupled to mass spectrometry (LC-MS/MS) is considered as a more specific tool for mycotoxin detection and confirmation. However, the implementation of this technique for the determination of patulin, especially in the context of multi-mycotoxin analysis, is limited due to ionization problems. In this study, the effect of different solvents, mobile phase additives and pH on the ionization and fragmentation pattern of patulin was investigated. The preliminary results showed that under alkaline conditions and using methanol as organic modifier, an intense and stable signal for the methanol-adduct of patulin was obtained in the positive electrospray ionization mode. The fragmentation of this protonated methanol-adduct gave a strong and stable product ion signal. The production spectra were overall more useful than those obtained with the protonated or the deprotonated molecule. These findings indicate the possibility of using the protonated methanol-adduct of patulin for its identification and quantification by LC-MS/MS. Further results that will be presented include the optimization, by means of experimental design, of the parameters that have an influence on the formation of the protonated methanol-adduct of patulin and on its fragmentation behaviour, as well as the inclusion of this toxin in a multi-mycotoxin LC-MS/MS method. This study is the first report of the LC-MS/MS determination of patulin using its protonated methanol-adduct. References: [1] Nielsen KF (2003) Mycotoxin production by indoor molds. Fungal Genetics and Biology. 39: 103-117