The organic market is growing rapidly. This is because customers expect organic food to be authentic and healthy. For plant products the awareness of pesticide residues is one main point in customers' decisions for organic food, but in terms of secondary plant compounds, antioxidants are also expected benefits of organically produced foods. For wheat the xanthophylls are one group of those secondary plant compounds. There are no recent studies about the influence of cultivation practices on the xanthophyll content. This study examined the influence of the farming system on the content of lutein and zeaxanthin. To evaluate this, samples of a long-term field trial were examined by comparing conventional (nonorganic) and organic produce grown under controlled conditions. Additionally, samples were examined from farm pairs located in Germany. Each of the pairs consisted of one organically and one conventionally producing farm, located in local neighborhood and cultivating the same wheat variety. To summarize, the influence of the farming system is very small. The differences are mainly caused by different kernel sizes (thousand-kernel weight), which are found to be correlated to the lutein content.

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The market for organic produce is growing since consumers lost confidence in conventional food products in view of food scandals in the EU. There is thus an urgent need for suitable methods that can be used to demonstrate the authenticity of organic produce. In addition, consumers expect health benefits from organic products. For that the question of secondary plant compounds has been intensively discussed. Whether produce from organic farming results in higher content of health-related substances has been examined in several studies but no clear evidence was found. Secondary plant compounds may also be used in authentication of organic products. In this literature review various factors which may influence the content of carotenoids and polyphenols as two important classes of secondary metabolites in carrots are evaluated. For polyphenols in carrots there is a lack of studies apart from the influence of the variety. It has been shown that variety and environmental factors, like climate and soil, have greater influence on the carotenoid content than cultivation related factors such as fertilization and weed control. In organic farming, more intensive attempts are required to select location-and production-related varieties. Without inclusion of these factors, which are not covered in the EU regulations, an authenticity test of organic produce using secondary plant compounds seems not possible. Further research is needed on basis of large data sets to test, whether the use of multivariate statistical methods could be a practical approach to the routine analysis.

<div>We present here an experimental session for undergraduate students, based on the reaction monitoring of the degradation of an organic pollutant (para-nitrophenol) by a Fenton-like reaction, catalysed by magnetite particles. <br></div><div>During the session, students realized a follow-up of the reaction by Gas Chromatography with an internal standard, and by UV-Visible spectrophotometry. <br></div>This session was a good starting point to numerous discussions about analytical chemistry, environmental chemistry.