Study of organic acids, volatile fraction and caseins of a new Halloumi-type cheese during ripening in whey brine

Organic acids, fat hydrolysis, volatile compounds and sensory characteristics of a new brine cheese which combines characteristics of Halloumi and Feta cheeses during its ripening in whey brine (100g NaCl L⁻¹) were studied. Thermotolerant protease of Mucor miehei as a coagulant enzyme and a mixture of thermotolerant starter cultures Enterococcus faecium 0165 (0.5% w/w) and Lactobacillus casei 80 10D were used. Good quality new Halloumi-type cheese was produced with higher proteolysis than traditional Halloumi cheese kept in whey brine. The volatile compounds identified comprised alcohols, aldehydes, ketones, acids, esters, hydrocarbons and sulphur compounds. Ethanol was the dominant volatile compound determined. Lactic acid was the dominant acid produced; its concentration increased during ripening, reaching a maximum value of 9929 mg kg⁻¹ at day 30. Acetic acid was also found in high amounts, which increased during cheese ripening. Lipolysis of cheese was not intense. The most abundant acids of the mature cheese were palmitic, oleic and acetic acid. The Halloumi-type cheese scored higher in the sensory analysis when fresh than did the mature cheese.     

LC–DAD–MS (ESI+) analysis of the phenolic content of Sorbus domestica fruits in relation to their maturity stage

The aim of this study was the detailed qualitative and quantitative analysis of the phenolic content of several extracts and fractions of Sorbus domestica fruits. The analysis was realized by LC–DAD–MS (ESI+). Twenty-four different extracts and fractions of five different maturity stages of the fruit were analyzed for comparison reasons in order to determine the most beneficial for health type of consuming. Sixty-two different phenolics were identified. There were significant qualitative and quantitative differentiations in the phenolic content among the different types of the fruits. All categories were rich in benzoic, phenylpropanoic and cinnamoylquinic acids and derivatives. Unripe fruit categories were also rich in flavonoids, while well matured fruit categories had a low content of flavonoids. Fruit pulp, which was proved to be a strong antioxidant according to previous research work, contained very low amounts of both acids and flavonoids, but its phenolic content was highly qualitatively differentiated from the other categories.     

Theoretical and experimental analysis of the thermal behaviour of a green roof system installed in two residential buildings in Athens,Greece

Measurements of the thermal behaviour of two residential buildings equipped with a green roof system have been performed in Athens, Greece. Experimental data have been used to calibrate detailed simulation tools and the specific energy and environmental performance of the planted roofs system has been estimated in detail. Simulations have been performed for free‐floating and thermostatically controlled conditions. The expected energy benefits as well as the possible improvements of the indoor thermal comfort have been assessed. It is found that green roofs have a limited contribution to the heating demand of insulated buildings operating under the Mediterranean climate. On the contrary, the green roof system is found to contribute highly to reduce the cooling load of thermostatically controlled buildings. For the considered residential buildings, a cooling load decrease of about 11% has been calculated. In parallel, it is found that green roofs contribute to improve thermal comfort in free‐floating buildings during the summer period. The expected maximum decrease of the indoor air and roof surface temperatures is close to 0.6°C. Such a decrease contributes to reduce by 0.1 the summer absolute Predicted Mean Vote Comfort Index levels in the building. Copyright © 2009 John Wiley & Sons, Ltd.     

Shocks in economic growth = shocking effects for food security?

The recent economic and financial turmoil raises the question on how global economic growth affects agricultural commodity markets and, hence, food security. To address this question, this paper assesses the potential impacts of faster economic growth in developed and emerging economies on the one hand and a replication of the recent economic downturn on the other hand. The empirical analysis uses AGLINK-COSIMO, a recursive-dynamic, partial equilibrium, supply–demand model. Simulation results demonstrate that higher economic growth influences demand more than supply, resulting in higher world market prices for agricultural commodities. Emerging economies tend to import more and to stock less in order to cover their demand needs, while the rest of the world increases its exports. The modelled faster economic growth also helps developing countries to improve their trade balance, but does not necessarily give them the incentive to address domestic food security concerns by boosting domestic consumption. A replication of an economic downturn leads to lower world prices, and while the magnitude of the effects decreases over time, markets do not regain their baseline levels within a 5-year period. Due to the lower world market prices, developing countries import more and increase their per capita food calorie intake. However, as developing countries become more import dependent, this also implies that they become more vulnerable to disruptions in agricultural world markets.     

Dissolved and particulate trace metal levels in the Saronikos Gulf, Greece, in 2004. The impact of the primary Wastewater Treatment Plant of Psittalia

The present study examines the concentrations of Cd, Cu, Mn, Ni, Pb and Zn in 2004 in the Saronikos Gulf, an embayment affected by anthropogenic inputs from the nearby metropolitan area of Athens. We investigated in particular the impact of the operation for a decade of the primary Wastewater Treatment Plant of Athens, which is located at Psittalia Island, on the levels of these metals in the marine environment of the gulf, few months before the inauguration of the secondary treatment. Therefore, the present work represents the needed baseline for any future comparisons and assessment of the impact of the secondary treatment. For two samplings carried out in May and September 2004 in a grid of fifteen stations, dissolved and particulate metal concentrations are, respectively, in the range 5.0–63 and 0.22–3.6 ng/L for Cd, 0.03–0.72 and 0.03–0.23 μg/L for Cu, 0.11–1.2 and 0.02–0.55 μg/L for Mn, 0.19–1.5 and 0.01–0.11 μg/L for Ni, 0.05–0.60 and 0.02–0.59 μg/L for Pb and 0.13–5.8 and 0.06–1.0 μg/L for Zn. The concentrations of the majority of the studied metals obtained in 2004 are comparable to those of the year 2000 and among the lowest detected in the Saronikos Gulf ever since the beginning of the MED-POL program twenty years ago. This stabilization is attributed to the operation of the wastewater treatment plant and offers an indication that the levels of trace metal pollution of the marine environment of the gulf are possibly reaching a steady state.     

Changes in vegetable microbiological quality introduced by processing methods

The main objective of this research was to investigate the effect in microbial quality of vegetables, because of the chain of buyers and sellers involved in the collection, processing and selling of vegetables, from the primary production sector up to the consumer level (from farm to table). Two processing plants and six hotels were selected and 240 vegetables, 30 vegetable containers, 18 water samples used for sanitation purposes and samples of 18 personnel's hands, were microbiologically analysed. Based on actual results and processing plants auditing, we conclude that initial vegetable microbial quality is critical. The storage, separation and packaging processes, cleaning procedures and retention time at processing plants can influence vegetable microbial quality. Buyers–sellers involved between vegetable production in primary sector and final consumer can offer a dramatic decrease in vegetable quality. The use of ISO 9001:2000 can improve product quality through techniques such as product traceability and resources management.     

Development of a faradic impedimetric immunosensor for the detection of Salmonella typhimurium in milk

The development of a faradic impedimetric immunosensor for the detection of S. typhimurium in milk is described for first time. Polyclonal anti-Salmonella was cross-linked, in the presence of glutaraldehyde, on gold electrodes modified with a single 11-amino-1-undecanethiol (MUAM) self-assembled monolayer (SAM) or a mixed SAM of MUAM and 6-mercapto-1-hexanol at a constant 1 + 3 proportion, respectively. The mixed SAM was also deposited in the presence of triethylamine, which was used to prevent the formation of interplane hydrogen bonds among amine-terminated thiols. The effect of the different surface modifications on both the sensitivity and the selectivity of the immunosensors was investigated. The alteration of the interfacial features of the electrodes due to different modification or recognition steps, was measured by faradic electrochemical impedance spectroscopy in the presence of a hexacyanoferrate(II)/(III) redox couple. A substantial amplification of the measuring signal was achieved by performing the immunoreaction directly in culture samples. This resulted in immunosensors with great analytical features, as follows: (i) high sensitivity; the response of the immunosensors increases with respect to the detection time as a consequence of the simultaneous proliferation of the viable bacteria cells in the tested samples; (ii) validity; the response of the immunosensors is practically insensitive to the presence of dead cells; (iii) working simplicity; elimination of various centrifugation and washing steps, which are used for the isolation of bacteria cells from the culture. The proposed immunosensors were successfully used for the detection of S. typhimurium in experimentally inoculated milk samples. The effect of different postblocking agents on the performance of the immunosensors in real samples was also examined.     

Comparative evaluation of two simple diffuse reflectance models for biological tissue applications

We present a comparative evaluation of two simple diffuse reflectance models for biological tissue applications. One model is based on a widely accepted and used in biomedical optics implementation of diffusion theory, and the other one is based on a semiempirical approach derived from basic physical principles. We test the models on tissue phantoms and on human skin, utilizing a standard six-around-one optical fiber probe for light delivery and collection. We show that both models are suitable for use with an optical fiber probe and illustrate the potential, applicability, and validity range of the models.