Glucosinolates (GLS) are sulfur rich, anionic secondary metabolites found principally in the plant order Brassicales. This review focuses on identifying the range of GLS structures identified to date and summarises the current state of taxonomic reclassifications of GLS producing plants. Those Brassica species that are available to growers in the UK are highlighted and progress in the aspects of analytical chemistry relevant to conducting accurate determinations of GLS content of foods is reviewed. The degradation and derivatisation workflows that have been utilized for conducting ''glucosinolate analysis'' are summarized. A review is made of aspects of extraction, isolation, determination of purity, ultraviolet (UV) and mass spectrometry (MS) parameters, extinction coefficients, UV response factors, quantification procedures, and the availability of stable isotope labeled internal standards, and certified reference materials. An electronic database of structures, formulae and accurate masses of both the 200 known, and a further 180 predicted GLS, is provided for use in mass spectrometry.

We report here the first confirmation of the recent Swedish findings of acrylamide in heated foods. The verification exercise used an LC-MS/MS method developed for the purpose as well as an established GCMS method for acrylamide analysis. LC-MS/MS was suitable for the direct determination of acrylamide in aqueous extracts of foods by isotope dilution mass spectrometry (IDMS) using triply deuterated acrylamide. Some food matrices were not suited to the new method and mixed-mode solid-phase extraction (SPE) was used to clean these extracts. The foods tested included UK versions of some of the key food groups analysed in Sweden. Also tested were some foods heated under home-cooking conditions. There was good agreement between the LC-MS/MS results and the GC-MS results and the levels of acrylamide found here were similar to those reported for the corresponding foods analysed in the Swedish study. The analyses confirmed that acrylamide is absent from the raw or boiled foods but present at significant levels in fried, grilled, baked and toasted foods. The highest result was 12000 microg kg(-1) acrylamide in overcooked oil-fried chips.

Although interindividual variation in isoflavone metabolism was high, intraindividual variation was low. Only concentrations of O-DMA in plasma and urine appeared to be influenced by sex. Chronic soy consumption does not appear to induce many significant changes to the gut metabolism of isoflavones other than higher beta-glucosidase activity.

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The urinary excretion of soya isoflavones and gut microflora metabolites was investigated in infants and children who had been fed soyabased infant formulas in early infancy. These infants and children were compared with cows'-milk formula-fed controls, to determine at what age gut microflora metabolism of daidzein to equol and/or O-desmethylangolensin (O-DMA) was established, and whether exposure to isoflavones in early infancy influences their metabolism at a later stage of development. Sixty infants and children (aged 4 months -7 years) participated in the study; thirty in each of the soya and control groups. There were four age groups. These were: 4 -6 months (seven in the soya group and seven in the control group); 7 -12 months (seven in the soya group and nine in the control group); 1 -3 years (six in the soya group and eight in the control group); 3 -7 years (ten in the soya group and six in the control group). Urine samples were collected to measure isoflavonoids by MS, and faecal samples were collected to measure gut-health-related bacterial composition, by fluorescent in situ hybridisation with oligonucleotide probes, and metabolic activity. A soya challenge (typically a soya yoghurt alternative product containing 4·8 g soya protein and on average 22 mg total isoflavones) was given to control-group infants (. 6 months) and children, and also to soya-group children that were no longer consuming soya, to determine their ability to produce equol and/or O-DMA. Urinary genistein, daidzein and glycitein were detected in all infants (4 -6 months) fed soya-based infant formula; O-DMA was detected in 75 % of infants but equol was detected in only 25 %. In the controls (4 -6 months), urinary isoflavonoids were very low or not detected. In the older age groups (7 months -7 years), O-DMA was found in the urine samples of 75 % of the soya group and 50 % of the controls, after the soya challenge. Equol excretion was detected in 19 % of the soya-group infants and children, and in only 5 % of the controls. However, in the oldest (3 -7 years) children, the proportion excreting O-DMA and equol was similar in both groups. Faecal bacterial numbers for bifidobacteria (P, 0·001), bacteroides and clostridia (P, 0·05) were significantly lower for the soya group compared with the control group. There appears to be no lasting effect of early-life isoflavone exposure on isoflavone metabolism. Soya isoflavone metabolism: Equol: Soya-based infant formula: Gut bacterial microflora

The analysis of 252 food samples (UK-produced and imported) purchased from a variety of retail outlets in the UK was undertaken for the presence of perfluorooctanesulphonic acid (PFOS), perfluorooctanoic acid (PFOA) and nine other perfluorocompounds (PFCs). A limit of quantification (LOQ) of 1 microg/kg was achieved for all target analytes, in all samples. Standard addition was used for quantification of PFC levels. All 11 of the targeted PFCs were detected in 75 individual food items. In 70% of the samples, including all meat other than offal, none of the analytes were present above the LOD. The highest levels found were 59 microg/kg perfluorooctanesulphonic acid (PFOS) and 63 microg/kg total PFCs (SigmaPFCs) in an eel sample, and 40 microg/kg PFOS (62 microg/kg SigmaPFCs) in a whitebait sample. The highest level in an offal sample was 10 microg/kg, in a wild roe deer liver. There were six samples with SigmaPFCs >15 microg/kg (fish, shellfish, crustaceans), a further seven samples with SigmaPFCs ranging 11-15 microg/kg (including a liver), nine with SigmaPFCs ranging 6-10 microg/kg (fish and livers), 31 with SigmaPFCs in the range 2-5 microg/kg (including kidneys, popcorn and processed peas) and a further 22 with SigmaPFCs close to the LOD of 1 microg/kg (including eggs and potatoes). These concentrations indicate that UK consumers are being exposed to a low level of PFC contamination from food. The estimated upper bound dietary intake of 10 ng/kg bodyweight (bw)/day of PFOS for average adult consumers is well below the 0.15 microg (150 ng)/kg bw tolerable daily intake (TDI) set by the European Food Safety Authority. The lower bound adult dietary intake estimate of 1 ng/kg bw/day is similar to estimates undertaken and reported in countries such as Canada, Germany and Spain.

The isoflavone aglycon and glucoconjugate content of commercially prepared and "home-prepared" high- and low-soy foods selected for use in an on-going nutritional study were measured by LC-MS. The daidzin, daidzein, 6"-O-malonyldaidzin, 6"-O-acetyldaidzin, genistein, genistin, 6"-O-malonylgenistin, 6"-O-acetylgenistin, glycitin, glycitein, 6"-O-malonylglycitin, and 6"-O-acetylglycitin content are expressed in terms of individual isoflavones, total isoflavone equivalents, and milligrams of isoflavones per portion served. Soybeans (774 mg x kg(-1) total isoflavones) and soybean-containing foods had the highest isoflavone content of the foods examined. The low-soy foods all contained very low concentrations (<8 mg x kg(-1) total isoflavones) of the isoflavone aglycons and glucoconjugates. High- and low-soy 11 day rotating menus were constructed from the analyzed foods to deliver 100.0 and 0.5 mg of isoflavones per day, respectively.

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