Iskanje po repozitoriju

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Opis: Determination of food authenticity is an important issue in quality control and food safety. Recent studies predict a growing demand for natural and more authentic food and beverage products. The quality and authenticity of apple juice is also of a great economic importance since the popularity and demand for apple juice consumption has increased. The growth of the market for organically produced apples and apple juice is due to the increasing demand for healthy food requirements, protection of the environment and the promotion of biotic diversity. Organic foods have a higher nutritional and health value, but they are more expensive, because their production is more difficult and less profitable. In addition to how food is produced, consumers are increasingly placing emphasis on food products of specific region, which are known for their unique natural flavours and taste. The presented thesis is based on four separate but closely interrelated studies, in which a combination of different isotopic ratios of bioelements (2H/1H, 13C/12C, 15N/14N, 18O/16O), multi-element analysis, and major primary and secondary metabolite profiles were exploited to differentiate the geographical origin and agricultural production practice (organic vs integrated/conventional) of Slovenian apples. These parameters were used to establish the first database of authentic Slovenian apple juice, which can be used to verify the authenticity of commercially available apple juice in Slovenia. The first preliminary study was entitled “Organic Cultivation ~ Geographical Origin (OCGO)” and was performed using apples from the 2009 growing season. Its aim was to examine the use of stable isotope and multi-element data for determining the geographical origin and agricultural production practice of fresh apple juices. Fruits of six apple (Malus domestica Borkh) cultivars (Topaz, Idared, Golden Delicious, Goldrush, Gala, Gloster) were collected from four different geographical regions of Slovenia (Alpine, Dinaric, Pannonian and Mediterranean) grown under organic and integrated/conventional orchard management systems. The results revealed that stable isotope parameters in sugar, pulp and water were the most significant variables for differentiating between the regions. Good separation was achieved between the geographical regions in Slovenia based on the δ18O and δ2H values in water and Rb and S levels in the apple fruit juice. The most significant variables that distinguished between organically and integrated/conventionally cultivated apples were the 15N/14N ratio and antioxidant activity of the apple juice. Significant differences were also observed in the ascorbic acid content of the juice. Based on these results the number and types of apples and the minimum number of samples needed from the same region for determining geographical origin were determined. The second study was called “Organic ~ Conventional Apple Cultivation” (OCAC) and was performed in 2010 and 2011 in a Gala apple orchard. The aim was to determine the effect of different fertilizers allowed either in organic or conventional/integrated agricultural regimes on different parameters. Quality parameters, isotopic composition of C in sugars and in pulp together with N and elemental analysis were investigated. The following five fertilizers were applied: Biosol and Plantella organic (organic) and Ca cyanamide, KAN and UREA (mineral) at a rate of 60 and 120 kg of nitrogen per hectare. From the obtained data it was possible to differentiate between organic and integrated/conventional apple production when taking into account the following parameters: mass, skin and flesh firmness (SFF), total soluble solids (TSS), and the content of Cl as well as δ15N and δ13C in the pulp. The “Organic Cultivation ~ Geographical Origin” (OCGO) study, which took place during the 2011 and 2012 growing seasons included a greater number of samples and samples from five different geographical regions: Alpine, Dinaric,
Ključne besede: apple juice, geographical origin, agricultural production practice, biomarkers, phenol compounds, elements, stable isotopes, Slovenia
Objavljeno v RUNG: 07.06.2016; Ogledov: 8038; Prenosov: 895
Celotno besedilo (3,97 MB)

Opis: Within the duration of three projects (J7-0363, L1-0437, L1-4280), in the period from 2008 to 2013, measurements of tritium (3H), 40K and γ-ray emitters of uranium (238U, 226Ra and 210Pb) and thorium (228Ra and 228Th) decay series in groundwaters of Slovenia were carried out. Tritium was also measured in precipitation at selected locations. Groundwater sampling sites were selected in order to cover the most representative lithological units that are found in Slovenia and were at the same time evenly distributed throughout the country. In total, 281 samples were measured from 120 different locations. Measurements in the period 2009-2013 have shown that tritium concentrations in precipitation in Ljubljana are for about 30% lower compared to those in Vienna, however they are in line with seasonal fluctuations observed in Vienna. This was an important information in the process of the reconstruction of past tritium concentrations in precipitation in Ljubljana (tritium curve) for the missing period between 1953 and 1981. Tritium curve represents the input data when determining the average age of water. In determining the influence of various parameters on the final interpretation of the groundwater age it has been found that the greatest uncertainty contribute the measurements of the tritium curve and the measurements of tritium in groundwater samples. Also, the interaction of other factors (continental effect, rainfall regime, infiltration) and the lack of knowledge of them may have a major impact on the misinterpretation of groundwater age. Based on tritium concentration, groundwaters were divided into 4 major categories, into groundwaters that are older than 100 years (tritium concentration was below the detection limit), groundwaters, where the older component prevails (concentration of tritium was between 0 and 2.5 TU), groundwaters with the age between 30 and 60 years (the concentration of tritium was on average 8 TU) and recent groundwaters with age up to 15 years (tritium concentration of about 6 TU). The natural background of γ-ray emitters was determined for each lithological unit. The most represented radionuclide was 40K with concentrations always above the detection limit. A dependency of 40K concentrations on nitrate was observed, especially in the recharge areas, where limestone prevailed. Other γ-ray emitters revealed some dependence on nitrate concentration, especially both radium isotopes (226Ra and 228Ra). The concentration of 210Pb in groundwaters is mainly due to the connection with the surface and consequently with atmospheric 210Pb. The highest concentrations of 238U and 228Ra were measured in groundwaters from recharge areas in clastic rocks with a clay component. In contrast to the expected, concentrations for all γ-ray emitters (except 210Pb) were the lowest or even not detectable, in groundwaters from recharge areas in igneous and metamorphic rocks. Among γ-ray emitters and categorization based on tritium concentrations, elevated concentrations of 238U were observed in groundwaters with prevailing older component. Elevated concentrations of 40K were also observed in them. The largest scattering of 210Pb and 40K concentrations was observed in recent waters, which indicates a connection with the surface and application of fertilizers.
Ključne besede: Groundwaters, Slovenia, tritium input curve, natural gamma-ray emitters background.
Objavljeno v RUNG: 05.10.2015; Ogledov: 6348; Prenosov: 210
Celotno besedilo (8,62 MB)