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Oregano is used worldwide both as spice and crude drug, which is mainly provided by species of Origanum genus. The quality of the product is usually determined by chemical analysis, whereas in food industrial applications sensory tests are also practised. The aim of the present study was a comparison of parallel quality investigations of oregano samples by a new and effective instrumental sensory evaluation method, the “electronic nose”, and by gas-chromatographic and human sensory analysis. The GC analysis of essential oil components revealed mainly differences between plant species (Origanum vulgare subsp. hirtum and Origanum majorana). Main components of the oil of the former taxon are carvacrol and thymol, while those of marjoram are terpinene-4-ol, ?-terpinene and terpinolene. A wholesale oregano sample showing considerable divergence from the other ones with respect to ratios of carvacrol, ß-caryophyllene ß-cubebene and thymol. It was assumed not to belong to ssp. hirtum. The electronic nose analysis, evaluated by PCA, proved to be an appropriate, rapid, non-destructive, reagent-less method for the reliable separation of all of the oregano samples based on their complex aroma features. Assumptions could be made about correlations between separation of samples by the instrumental sensors and proportions of terpenoid compounds of the oil established by GC in some cases only. The varying essential oil content of the samples did not influence the success of instrumental evaluation. The instrumental and human sensory analysis showed similar results: varieties of O. majorana could be well distinguished on the basis of their complex aroma, while their gas-chromatograms did not show characteristic differences. The results call the attention that quality evaluation of drug items of aromatic plants should be oriented in different directions, considering the current utilisation area of the items.
Tomatoes (Solanum lycopersicon L.) are one of the most important and most widely consumed vegetables in the world. The fruit contains considerable amount of different phytonutrients such as carotenoids, tocopherols, and vitamin C. In the present work, effects of some abiotic factors on the concentration of phytonutrients were investigated in tomato cultivated in two different types of soil. It was found that the type of soil had slight effect on the most important vital nutrients, while the ecological factors, particularly precipitation and average temperature 3 weeks before harvest, were of significant influence on such nutrients. It was found that low temperature and high precipitation before harvest caused the levels of carotenoids, tocopherol, and vitamin C to significantly increase by 65%, 46%, and 28%, respectively.
Winter wheat (Triticum aestivum L.) yield samples taken from a consecutive series of crop years representing drought, normal and moist conditions at the Nagygombos experimental site of the Szent István University have been evaluated. The impact of N topdressing and crop year conditions on the performance of protein and wet gluten content were studied.The results suggest that ascending levels of N topdressing, and increased number of applications had a beneficial effect on the protein content, as well as on wet gluten values. Crop year had a significant effect on quality manifestation. The drier the crop year, the better the recorded quality performance. The magnitude of changes was bigger in case of gluten than in that of protein values. There were minor differences between the two varieties examined, especially in their response patterns to nitrogen supply. Dough formation depends mainly on the gliadin/ glutenin ratio, but there is less information on the agronomic and climatic impacts that may cause alterations in that.
Anti-nutritive components in multi resistant potato cultivars were investigated in relation to conventional and organic farming for three years. Glycoalkaloids, nitrate, nitrite, asparagine, and glutamine contents of tubers were examined. Farming technology was found not to have an effect on the level of glycoalkaloids, which was influenced mostly by the genotype and season. Nitrogen fertilisation caused significant increase in nitrate, asparagine, and glutamine contents as compared to organic farming. Nitrite content was found to be more independent of farming technologies than nitrate. Tubers of cultivar Rioja had the lowest nitrate content irrespective of season or technology. In conclusion, the absolute amount and changes of different anti-nutritive components of potato tubers were influenced differently by the technology, genotype, and season in a complex manner. Organic farming had no effect on the glycoalkaloid content, but the nitrate levels had a tendency to be lower compared to conventional farming. This can be seen as a positive effect of organic farming.
Abstract
In recent years response surface analysis has been increasingly used to optimise membrane separation. It has many advantages, such as reducing the number of experiments to be performed, which requires lower energy consumption and significantly less laboratory work. For more accurate data analysis and forecasting, mathematical models are used that analyse the relevance of the factors examined and the interaction effects between the factors. In this research, two experimental designs that use response surface methodology are presented, namely, the central composite design and the Box–Behnken design. After the general characterisation of the experimental designs, their application in membrane technology is presented.
