Exploration of Betalains and Determination of the Antioxidant and Cytotoxicity Profile of Orange and Purple Opuntia spp. Cultivars in Greece

Plant Foods for Human Nutrition - Replacing synthetic dyes with natural pigments has gained great attention over the past years in the food industry, due to the increased alertness of consumers for...     

Geographical characterization of greek virgin olive oils (cv. Koroneiki) using 1H and 31P NMR fingerprinting with canonical discriminant analysis and classification binary trees

This work deals with the prediction of the geographical origin of monovarietal virgin olive oil (cv. Koroneiki) samples from three regions of southern Greece, namely, Peloponnesus, Crete, and Zakynthos, and collected in five harvesting years (2001-2006). All samples were chemically analyzed by means of 1H and 31P NMR spectroscopy and characterized according to their content in fatty acids, phenolics, diacylglycerols, total free sterols, free acidity, and iodine number. Biostatistical analysis showed that the fruiting pattern of the olive tree complicates the geographical separation of oil samples and the selection of significant chemical compounds. In this way the inclusion of the harvesting year improved the classification of samples, but increased the dimensionality of the data. Discriminant analysis showed that the geographical prediction at the level of three regions is very high (87%) and becomes (74%) when we pass to the thinner level of six sites (Chania, Sitia, and Heraklion in Crete; Lakonia and Messinia in Peloponnesus; Zakynthos). The use of classification and binary trees made possible the construction of a geographical prediction algorithm for unknown samples in a self-improvement fashion, which can be readily extended to other varieties and areas.     

Aspects on the relief of living surfaces using atomic force microscopy allow “art” to imitate nature

The visualization of the surface of biological samples using an atomic force microscope reveals features of the external relief and can resolve very fine and detailed features of the surface. We examined specimens from the skin of the amphibians Salamandra salamandra Linnaeus, 1758, Lyciasalamandra luschani basoglui Baran & Atatür, 1980 and Mesotriton alpestris Laurenti, 1768, and from the surface of pollen grains of the plant species Cyclamen graecum Link, 1835 and Cistus salviifolius Linnaeus, 1753, which exhibit certain interesting features, imaged at the nanoscale level. It is likely that the relief influences the attributes of the interfaces between the tissues and the environment. We found that the microsculpture increases in size the surface of the examined tissues and this might be particularly important for their performance in the field. Microsculpturing of amphibians' skin may affect water regulation, dehydration and rehydration, and cutaneous gas exchange. Pollen grain relief might affect the firmness of the contact between pollen surface and water droplets. High resolution imaging of the external relief showed that roughening might induce wetting and influence the water status of the specimens. In addition, roughness affects the radius of water droplets retained in between the projections of the external relief. Roughness of the tissues was highly correlated with their vertical distance, whereas surface distances were highly correlated with horizontal distances. By enabling a more detailed characterization of the external sculptures, through sophisticated techniques, a more comprehensive examination of the samples indicates similarities among different living tissues, originated from different kingdoms, which can be attributed to environmental conditions and physiological circumstances.     

Influence of combined grazing by wild boar and small ruminant on soil and plant nutrient contents in a coppice oak forest

Limited information is available about the impact of grazing on soil and plant nutrient contents in Mediterranean deciduous oak forests grazed by both livestock and wild life. Thus, the main objective of this study was to investigate the effect of wild boar and small ruminants grazing in a coppice oak forest in N Greece. Eight even‐aged stands of similar canopy cover and site quality were selected: four stands with long‐time grazing mainly by wild boar and four stands with long‐time grazing by sheep and goats. A plot of 150 m² in each of the stands was fenced in order to be protected from grazing. A similarly sized plot open to grazing was assigned next to the fenced plot. Species composition was recorded in fenced and grazed plots. Soil samples and individual plants of the dominant palatable grass species Dactylis glomerata and Brachypodium sylvaticum were collected in every fenced and grazed plot. These samples were analysed for contents of nutrients. The results indicated that grazing increased organic matter, C, and total N, P and Ca, while it had no effect on the plant nutrients Mg, Na, K and all micronutrients, and pH as well. Wild boar grazing had a significantly negative impact on the concentrations of Na, Fe, Zn, and Mn in the soil. Beside a decrease in K and Mn, grazing had minimal effects on the contents of plant nutrients. Conversely, wild boar grazing increased the contents of several nutrients such as N, Na, Cu and Fe in plant tissue. It seems that species composition was more affected by the topography and management than by the soil features as revealed by RDA analysis. The results of this study indicate that it is important to maintain moderate small ruminant grazing intensity for the sustainable multi‐disciplinary management of coppice oak forests. It is also important to control wild boar population in order to facilitate ecosystem process, soil preservation and forage quality.     

Study of variegated and white flower petals of Capparis spinosa expanded at dusk in arid landscapes

In this study,we provide the first evidence of two pairs of petals of the rapidly expanded and short-lived nocturnal flowers of Capparis spinosa L.(caper)during the prolonged drought period in Eastern Mediterranean region.The corolla of the winter-deciduous,perennial C.spinosa consists of two pairs of petals:a pair of white distinct petals and a pair of connate variegated petals with green basal parts.The results indicated the presence of substantially different amounts of chlorophyll in the two pairs of petals,while their carbohydrates’content is comparable with that of the green sepals.High resolution imaging of petal surfaces of short-lived flowers of C.spinosa, obtained by using scanning electron microscopy,revealed stomata on the adaxial epidermis on both the white and the green parts of the variegated petals;while dense hairs were found on the surface of the abaxial green parts of the variegated petals.Adaxial,epidermal cells of the variegated petals,viewed using atomic force microscopy,possess a submicron,cuticular microfolding that differs between the white and the green parts of the petals.It appears that microridges on the adaxial,white parts of petals of C.spinosa compensate for an increase in cell surface area of the short lived petals,while the roughness of the green parts of petals was found to be higher than that of the white parts.Thus,the micromorphology of surfaces of epidermal cells is expected to affect optical properties and wettability of the floral tissues.These findings may be particularly important for understanding the performance of the short-lived petals of C.spinosa,which are exposed to dryland environments.     

Classification of edible oils by employing 31P and 1H NMR spectroscopy in combination with multivariate statistical analysis. A proposal for the detection of seed oil adulteration in virgin olive oils

A combination of (1)H NMR and (31)P NMR spectroscopy and multivariate statistical analysis was used to classify 192 samples from 13 types of vegetable oils, namely, hazelnut, sunflower, corn, soybean, sesame, walnut, rapeseed, almond, palm, groundnut, safflower, coconut, and virgin olive oils from various regions of Greece. 1,2-Diglycerides, 1,3-diglycerides, the ratio of 1,2-diglycerides to total diglycerides, acidity, iodine value, and fatty acid composition determined upon analysis of the respective (1)H NMR and (31)P NMR spectra were selected as variables to establish a classification/prediction model by employing discriminant analysis. This model, obtained from the training set of 128 samples, resulted in a significant discrimination among the different classes of oils, whereas 100% of correct validated assignments for 64 samples were obtained. Different artificial mixtures of olive-hazelnut, olive-corn, olive-sunflower, and olive-soybean oils were prepared and analyzed by (1)H NMR and (31)P NMR spectroscopy. Subsequent discriminant analysis of the data allowed detection of adulteration as low as 5% w/w, provided that fresh virgin olive oil samples were used, as reflected by their high 1,2-diglycerides to total diglycerides ratio (D > or = 0.90).