Antioxidant activity of extracts obtained by different isolation procedures from some aromatic herbs grown in Lithuania

An increasing demand for natural additives has shifted the attention from synthetic to natural antioxidants. The present work examines the potential of some aromatic herbs grown in Lithuania as a source of natural antioxidants: marjoram (Majorana hortensis Moench), catnip (Nepeta cataria L), oregano (Origanum vulgare L), lavender (Lavandula angustifolia Mill), thyme (Thymus vulgaris L), hyssop (Hyssopus officinalis L), anise hyssop (Lophantus anisatus Benth), and sage (Salvia officinalis L). Dried herb samples were submitted to extraction with supercritical CO₂, acetone or methanol/water and hydrodistillation. Deodorised herb samples (after removal of essential oil) were also extracted with acetone. The antioxidant activity of these extracts, essential oils and dried deodorised aqueous extracts was assessed by the β-carotene bleaching test (diffusion and spectrophotometric methods). The highest yields of extracts were obtained using polar solvents. Thyme and sage acetone oleoresins showed high antioxidant activity in the tests performed and were regarded as the most promising sources. © 1998 SCI.     

An overview of solar energy applications in buildings in Greece

This work classifies and describes the main fields of solar energy exploitation in buildings in Greece, a country with high solar energy capacities. The study focuses on systems and technologies that apply to residential and commercial buildings following the prevailing design and construction practices (conventional buildings) and investigates the effects of the architectural and constructional characteristics of these buildings on the respective applications. In addition, it examines relevant applications in other building categories and in buildings with increased ecological sensitivity in their design and construction (green buildings). Through its findings, the study seeks to improve the efficiency and broaden the scope of solar energy applications in buildings in Greece to the benefit of their energy and environmental performance.     

Local challenges in the promotion of renewable energy sources: The case of Crete

Crete, the largest Greek island, attracts about 20% of the total Greek tourist activity and hosts more than 50% of all renewable energy projects situated in the Hellenic island territories. In this article, we probe the comparatively successful promotion of renewable energy applications among Cretan municipalities by identification of key components and drivers of local dynamics which facilitate the development of such innovative and collective projects. We then refer to a theoretical economic grid highlighting the strength of local factors (i.e. social and institutional forces) in co-ordination mechanisms. We conclude that for the case of Crete, both internal factors (such as local acceptance) and external elements (such as macrostructure) play a core role in successful implementation of renewable energy, and from this we propose a number of facilitating conditions which could help promote renewable energy production on other islands.     

Metabolomics of acid whey derived from Greek yogurt

Acid whey, a byproduct of Greek yogurt production, has little commercial value due to its low protein content and is also environmentally harmful when disposed of as waste. However, as a product of microbial fermentation, acid whey could be a rich source of beneficial metabolites associated with fermented foods. This study increases understanding of acid whey composition by providing a complete metabolomic profile of acid whey. Commercial and laboratory-made Greek yogurts, prepared with 3 different bacterial culture combinations, were evaluated. Samples of uncultured milk and cultured whey from each batch were analyzed. Ultra-high-performance liquid chromatography–tandem mass spectrometry metabolomics were used to separate and identify 477 metabolites. Compared with uncultured controls, acid whey from fermented yogurt showed decreases in some metabolites and increases in others, presumably due to the effects of microbial metabolism. Additional metabolites appeared in yogurt whey but not in the uncultured control. Therefore, the effect of microbial fermentation is complex, leading to increases or decreases in potentially bioactive bovine metabolites while generating new microbial compounds that may be beneficial. Metabolite production was significantly affected by combinations of culturing organisms and production location. Differences between laboratory-made and commercial samples could be caused by different starting ingredients, environmental factors, or both.     

Physicochemical and microbiological changes of “Souvlaki” – A Greek delicacy lamb meat product: Evaluation of shelf-life using microbial,colour and lipid oxidation parameters

Fresh Souvlaki-type lamb meat was packaged under vacuum (VP) and modified atmospheres (MAs) and stored under refrigeration (4 °C) for a period of 13 days. The following gas mixtures were used: M1: 30%/70% (CO₂/N₂) and M2: 70%/30% (CO₂/N₂). Identical samples were aerobically-packaged and used as control samples. Quality evaluation of product stored under the above packaging conditions was conducted using physicochemical and microbiological analyses. Of the chemical parameters determined, pH values of product showed no significant differences for all packaging treatments as a function of storage time. Lipid oxidation of lamb meat was enhanced by aerobic storage and gas mixture M1, whereas VP and gas mixture M2 controlled lipid oxidation to a greater extent. Souvlaki colour stability (as determined by a^∗, b^∗ and L^∗ values) was not negatively affected by either VP or MA conditions during the 13 days of storage. Of the two MAs and VP used, gas mixture M2 and VP were the most effective treatments for the inhibition of total viable counts (TVC), Pseudomonas spp., yeasts and Brochothrix thermosphacta in Souvlaki meat. Lactic acid bacteria (LAB) and Enterobacteriaceae were also found in the microbial flora of Souvlaki and increased during storage under all packaging conditions used. Based on microbiological analysis data and on the proposed a^∗ values, the use of VP and MAP (M2: 70%CO₂/30N₂) extended the shelf-life of “Souvlaki” meat stored at 4 °C by approximately 4–5 days compared to aerobic packaging.     

Chemical characteristics,fatty acid composition and conjugated linoleic acid (CLA) content of traditional Greek yogurts

Many studies with conjugated linoleic acid (CLA) indicate that it has a protective effect against mammary cancer. Because dairy products are the most important dietary sources of CLA, we have investigated the CLA concentrations and additionally the fatty acid profiles and chemical composition of several commercial, traditional, Greek yogurts from different geographical origin. The fat content of yogurts was in the order of goat < cow < sheep. Cow, sheep and goat milk yogurts contain respectively 0.128–1.501, 0.405–1.250 and 0.433–0.976 g CLA/100 g fat. Low-fat milk yogurts showed lower values of c-9, t-11 CLA content on lipid basis compared to full-fat yogurts. Samples from mountain areas showed average c-9, t-11 CLA content higher than those from prairie districts. The highest amounts of saturated fatty acids (SFA) were found in low-fat yogurts, of monounsaturated fatty acids (MUFA) in sheep milk yogurts and of polyunsaturated fatty acid (PUFA) in low-fat cow milk yogurts.     

The use of a non‐equilibrated solid phase microextraction method to quantitatively determine the off‐notes in mint and other essential oils

The undesirable top notes or off‐notes found in mint, clary sage, and cedarwood oils could be quantitatively determined using a non‐equilibrated solid phase microextraction/gas chromatography/selected ion monitoring/mass spectrometry (SPME/GC/SIM‐MS) technique. Using the low threshold components, dimethyl sulfide, 2‐methylpropanal, 2‐methylbutanal, and 3‐methylbutanal, which are associated with the off‐notes of these oils, their levels could be reproducibly quantitatively determined. The highest level of off‐notes was found in a sample of Scotch spearmint oil where the levels of the four constituents were, dimethyl sulfide (238 µg g^?1), 2‐methylpropanal (286 µg g^?1), 2‐methylbutanal (1048 µg g^?1) and 3‐methylbutanal (1489 µg g^?1). These quantitative results in combination with sensory evaluations could provide for a powerful overall assessment of essential oil quality. Copyright © 2004 Society of Chemical Industry     

Selection and socialization of risky drinking during the college transition: The importance of microenvironments associated with specific living units.

Risky drinking among college students differs as a function of living types, with living at Greek houses as a major risk factor. Both self-selection based on prior drinking and socialization through living environments have been shown to account for this association. However, it is not clear whether selection and socialization processes occur as a function of specific living units within living types. Multilevel models using a prospective sample of incoming college students (N = 2,392) demonstrated that (1) precollege drinking based selection into specific living units occurred within both fraternity houses and residence halls (beyond selection into the Greek system in general) and (2) socialization of extremely risky drinking among certain fraternity houses was greater than other houses (beyond greater socialization of living at fraternity houses than residence halls in general). Living unit-level precollege correlates (i.e., college attendance motives and cigarette use) and college correlates (i.e., peer drinking norms and alcohol availability) accounted for most of the selection and socialization effects. These findings highlight the importance of micro-environments associated with specific living units in risky drinking during the college transition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)