Charakterisierung von Getreide aus ökologischem und konventionellem Anbau - Anwendung von Protein-Profiling-Techniques und Inhaltsstoffanalysen

Ökologisch und konventionell angebauter Weizen aus dem kontrollierten DOK-Feldversuch (Schweiz) wurde umfassend hinsichtlich biochemischer Unterschiede charakterisiert. Dazu wurden die Profiling-Techniken Proteomics und Metabolomics, sowie Analytik von Einzelverbindungen eingesetzt. Metaboliten-Profile und Analytik von Einzelverbindungen ergaben geringfügige Unterschiede im DOK-Weizen aus unterschiedlichen Anbauvarianten. Statistisch signifikante Abweichungen konnten meist nur für eines von zwei untersuchten Anbaujahren gefunden werden. Abweichungen lagen innerhalb der bekannten Schwankungsbreiten bei Weizen. Beim Protein-Profiling, durchgeführt mit zweidimensionaler Gel-Elektrophorese, Bildauswertung und Proteinidentifizierung wurden die relativen Gehalte von ca. 1000 Proteinen in Weizen bestimmt. Die Gehalte von 16 Proteinen waren in ökologischem und konventionellem Weizen aus zwei Anbaujahren signifikant verschieden. Diese 16 Proteine bilden eine Signatur, anhand derer die Anbauvarianten des DOK-Weizens unterschieden werden können. In einem nächsten Schritt soll untersucht werden, ob diese Signatur gleichfalls bei ökologischem und konventionellem Weizen gilt, der von verschiedenen Standorten und von verschiedenen Sorten stammt. Vor dem Hintergrund des komplexen Gesamtstoffwechsels von Pflanzen ergeben die relativ wenigen mit verschiedenen Gehalten auftretenden Proteine keinen Hinweis auf Änderungen von Stoffwechselaktivitäten, die für die menschliche Ernährung kritisch wären. Die signifikante Reduzierung des Gesamtproteingehalts ist unter Ernährungsgesichtspunkten eher ungünstig, bei der in Deutschland üblichen Zusammensetzung der Diät aber unbedenklich. Zusammenfassend wird mit Blick auf die Ergebnisse des Protein-Profiling, des Metaboliten-Profiling und der Analytik von Einzelverbindungen gefolgert, dass ökologischer und konventioneller DOK-Weizen hinsichtlich der untersuchten Parameter ernährungsphysiologisch gleich wertvoll ist

Free sugars in spelt wholemeal and flour

Spelt (Triticum aestivum L. ssp. spelta) is experiencing a renaissance in Europe and North America, where it is used for baking, brewing, production of pasta, and self-supplied animal feed. One of the characteristics of spelt is that in comparison to modern wheat it is more resistant to harsh climatic and poor soil conditions. In contrast to wheat the hulls remain on the grain after threshing. Drawbacks are that spelt yields are quite low compared to modern wheat. The subject of the current study was to gain information about the composition of soluble sugars and their concentrations in spelt wholemeal and flour. High performance liquid chromatography (HPLC) was used for analysis. Concentrations of nine free sugars in spelt wholemeal and flour are reported. Flour cumulative free sugar concentrations were 63% lower than in wholemeal. For comparisons, we also analyzed wholemeal of wheat. The cumulative concentration of free sugars was 27% lower than in spelt wholemeal. However, when published data for sugar concentration ranges of wheat are taken into account, the total concentration of free sugar was not different between spelt and modern wheats. Low concentrations of xylose and stachyose were detected in spelt. Higher concentrations of fructans such as 1-kestose and kestotetraose were detected in spelt when compared with wheat. Generally, concentrations of free sugars in spelt were in the range of free sugar levels published for wheat, except for maltose which was higher in spelt

Nutritional quality of organic and conventional wheat

The popularity of organic food and the farming area managed according to organic agriculture practices have been increasing during the last years. It is not clear, whether foods from organic and conventional agriculture are equal with respect to nutritional quality. We chose wheat (Triticum aestivum L., cv. Titlis) as one of the most important crop plants to determine a range of substances relevant for human nutrition in crops from organic and conventional agriculture systems. Wheat grains of 2003 originating from a long term field experiment, the Swiss DOK trial, consisting of bio-dynamic, bio-organic and conventional farming systems were used. Thousand seed weight, protein content, phosphate levels, antioxidative capacity, levels of phenols, fibre, fructan, oxalate and phytic acid were determined in whole wheat meal from the various organic and conventional growing systems of the DOK trial. Levels of these substances fell into a range that is known to occur in other wheat crops, indicating that wheat from the DOK trial was not special. Clearcut differences were observed for none-fertilised wheat, which was significantly lowest in thousand seed weight, protein and significantly highest in total oxalate. For the majority of the nutritionally important substances analysed, there were no significant differences between bio-dynamic, bio-organic, and conventional growing systems. Only protein content and levels of fibres were statistically different. Taken together, the magnitude of observed variations was very small. The results of our investigations do not provide evidence that wheat of one or the other agriculture system would be better or worse

Charakterisierung von Getreide aus ökologischem und konventionellem Anbau - Anwendung von Protein-Profiling-Techniques und Inhaltsstoffanalysen

Ökologisch und konventionell angebauter Weizen aus dem kontrollierten DOK-Feldversuch (Schweiz) wurde umfassend hinsichtlich biochemischer Unterschiede charakterisiert. Dazu wurden die Profiling-Techniken Proteomics und Metabolomics, sowie Analytik von Einzelverbindungen eingesetzt. Metaboliten-Profile und Analytik von Einzelverbindungen ergaben geringfügige Unterschiede im DOK-Weizen aus unterschiedlichen Anbauvarianten. Statistisch signifikante Abweichungen konnten meist nur für eines von zwei untersuchten Anbaujahren gefunden werden. Abweichungen lagen innerhalb der bekannten Schwankungsbreiten bei Weizen. Beim Protein-Profiling, durchgeführt mit zweidimensionaler Gel-Elektrophorese, Bildauswertung und Proteinidentifizierung wurden die relativen Gehalte von ca. 1000 Proteinen in Weizen bestimmt. Die Gehalte von 16 Proteinen waren in ökologischem und konventionellem Weizen aus zwei Anbaujahren signifikant verschieden. Diese 16 Proteine bilden eine Signatur, anhand derer die Anbauvarianten des DOK-Weizens unterschieden werden können. In einem nächsten Schritt soll untersucht werden, ob diese Signatur gleichfalls bei ökologischem und konventionellem Weizen gilt, der von verschiedenen Standorten und von verschiedenen Sorten stammt. Vor dem Hintergrund des komplexen Gesamtstoffwechsels von Pflanzen ergeben die relativ wenigen mit verschiedenen Gehalten auftretenden Proteine keinen Hinweis auf Änderungen von Stoffwechselaktivitäten, die für die menschliche Ernährung kritisch wären. Die signifikante Reduzierung des Gesamtproteingehalts ist unter Ernährungsgesichtspunkten eher ungünstig, bei der in Deutschland üblichen Zusammensetzung der Diät aber unbedenklich. Zusammenfassend wird mit Blick auf die Ergebnisse des Protein-Profiling, des Metaboliten-Profiling und der Analytik von Einzelverbindungen gefolgert, dass ökologischer und konventioneller DOK-Weizen hinsichtlich der untersuchten Parameter ernährungsphysiologisch gleich wertvoll ist

Modulation of carbon and nitrogen metabolism, and of nitrate reductase, in untransformed and transformed Nicotiana plumbaginifolia during CO2 enrichment of plants grown in pots and in hydroponic culture

International audienceTransformed plants of Nicotiana plumbaginifolia Viv. constitutively expressing nitrate reductase (35S-NR) or b-glucuronidase (35S-GUS) and untransformed controls were grown for two weeks in a CO 2enriched atmosphere. Whereas CO 2 enrichment (1000 ll á l A1) resulted in an increase in the carbon (C) to nitrogen (N) ratio of both the tobacco lines grown in pots with vermiculite, the C/N ratio was only slightly modi®ed when plants were grown in hydroponic culture in high CO 2 compared to those grown in air. Constitutive nitrate reductase (NR) expression per se did not change the C/N ratio of the shoots or roots. Biomass accumulation was similar in both types of plant when hydroponic or pot-grown material, grown in air or high CO 2 , were compared. Shoot dry matter accumulation was primarily related to the presence of stored carbohydrate (starch and sucrose) in the leaves. In the potgrown tobacco, growth at elevated CO 2 levels caused a concomitant decrease in the N content of the leaves involving losses in NO À 3 and amino acid levels. In contrast, the N content and composition were similar in all plants grown in hydroponic culture. The 35S-NR plants grown in air had higher foliar maximum extractable NR activities and increased glutamine levels (on a chlorophyll or protein basis) than the untransformed controls. These increases were maintained following CO 2 enrichment when the plants were grown in hydroponic culture, suggesting that an increased ¯ux through nitrogen assimilation was possible in the 35S-NR plants. Under CO 2 enrichment the NR activation state in the leaves was similar in all plants. When the 35S-NR plants were grown in pots, however, foliar NR activity and glutamine content fell in the 35S-NR transformants to levels similar to those of the untransformed controls. The dierences in NR activity between untransformed and 35S-NR leaves were much less pronounced in the hydroponic than in the pot-grown material but the dierence in total extractable NR activity was more marked following CO 2 enrichment. Foliar NR message levels were decreased by CO 2 enrichment in all growth conditions but this was much more pronounced in potgrown material than in that grown hydroponically. Since b-glucuronidase (GUS) activity and message levels in 35S-GUS plants grown under the same conditions of CO 2 enrichment (to test the eects of CO 2 enrichment on the activity of the 35S promoter) were found to be constant, we conclude that NR message turnover was speci®cally accelerated in the 35S-NR plants as well as in the untransformed controls as a result of CO 2 enrichment. The molecular and metabolic signals involved in increased NR message and protein turnover are not known but possible eectors include NO À 3 , glutamine and asparagine. We conclude that plants grown in hydroponic culture have greater access to N than those grown in pots. Regardless of the culture method, CO 2 enrichment has a direct eect on NR mRNA stability

Nutritional quality of organic and conventional wheat

The popularity of organic food and the farming area managed according to organic agriculture practices have been increasing during the last years. It is not clear, whether foods from organic and conventional agriculture are equal with respect to nutritional quality. We chose wheat (Triticum aestivum L., cv. Titlis) as one of the most important crop plants to determine a range of substances relevant for human nutrition in crops from organic and conventional agriculture systems. Wheat grains of 2003 originating from a long term field experiment, the Swiss DOK trial, consisting of bio-dynamic, bio-organic and conventional farming systems were used. Thousand seed weight, protein content, phosphate levels, antioxidative capacity, levels of phenols, fibre, fructan, oxalate and phytic acid were determined in whole wheat meal from the various organic and conventional growing systems of the DOK trial. Levels of these substances fell into a range that is known to occur in other wheat crops, indicating that wheat from the DOK trial was not special. Clear-cut differences were observed for none-fertilised wheat, which was significantly lowest in thousand seed weight, protein and significantly highest in total oxalate. For the majority of the nutritionally important substances analysed, there were no significant differences between bio-dynamic, bio-organic, and conventional growing systems. Only protein content and levels of fibres were statistically different. Taken together, the magnitude of observed variations was very small. The results of our investigations do not provide evidence that wheat of one or the other agriculture system would be better or worse