New trends in food processing

In this work some of the newest trends in food processing are reviewed. This revision intends to provide an updated overview (including works published until February 2001) on the newest food processes, including food manufacturing, preservation, and control. Modern processes for food and food ingredients manufacturing based on membrane technology, super-critical fluid technology, and some applications of biotechnology are presented, mainly applied to obtain functional foods, "all-natural" enriched foods, probiotics and prebiotics. Also included is a critical assessment concerning non-thermal preservation techniques used for food preservation, such as high hydrostatic pressure, pulsed electric fields, ultrasound, pulsed light, hurdle systems, etc. Finally, a group of new analytical techniques (i.e., molecular techniques such as Polymerase Chain Reaction (PCR), food image analysis, and biosensors) and their use for food and process control is reviewed.     

Bogotá and Medellín: Architecture and Politics

In the last 15 years, Bogotá and Medellín, Colombia's two largest cities, have undergone urban renaissances. These are a direct result of a political will to tackle the social, economic and physical segregation caused by the large-scale urban migrations of the 1970s and 1980s, which resulted in informal developments that were often isolated from central urban areas with no infrastructure. Lorenzo Castro and Alejandro Echeverri describe the shared experiences and distinct approaches of each city. Copyright © 2011 John Wiley & Sons, Ltd.     

Effects of postharvest treatments on fruit quality of sweet pepper at low temperature

BACKGROUND: Postharvest storage of sweet pepper fruits (Capsicum annuum L.) at low temperatures could impair their physical and chemical composition. Therefore, maintenance of essential nutrition support or altered gas exchange could preserve fruit quality, minimizing chilling injury. Thus our aim was to determine the response to postharvest application of a low concentration of nitrogen (urea) or antitranspirant (pinolene) during a period of 21 days at 5 °C. RESULTS: The results indicate that storage at 5 °C was effective with respect to maintaining firmness of sweet pepper fruits for 21 days, while application of antitranspirant increased firmness compared with non‐sprayed fruits. Additionally, urea maintained color while increasing total phenolics and the activity of catalase and ascorbate peroxidase, lowering lipid peroxidation. Composition of free amino acids was affected to a minor extent. CONCLUSION: Maintaining quality is of paramount importance in the postharvest period. This study shows the effect of both temperature and spraying treatments with regard to maintaining fruit quality during this period, and provides new insights into the physiological role of enzymes of the antioxidant system during pepper storage at low temperature. Copyright © 2010 Society of Chemical Industry     

Characterisation of major taste and health-related compounds of four strawberry genotypes grown at different Swiss production sites

Individual sugars, organic acids, anthocyanins and vitamin C were quantified in strawberry fruits of four newly-bred cultivars grown at two production sites in Switzerland with different soil, climatic conditions and altitudes (1060 and 480 m above sea level). All the measured compounds were significantly influenced by genotype. Pelargonidin-3-glucoside was the main anthocyanin present in all cultivars, while the presence of other pelargonidin derivatives was genotype-dependent. Differences of about 2-fold were observed among the studied cultivars for their vitamin C content. In the mountain region, where plants produced a higher fruit yield over a shorter period, the concentration of both health and taste-related compounds was detrimentally affected. In particular, the vitamin C content in the fruits was negatively related to the average yield per day. However, the compositional variations of strawberry fruits in response to different production sites were genotype specific. Within the four cultivars studied, cv. Antea was most affected by the production site, showing generally lower contents of all analysed compounds when cultivated at higher altitudes, whereas cv. Clery seemed to have the more consistent chemical composition, regardless of production site. The results presented in this work corroborate the dominant role of strawberry genotype over environmental factors.     

Tissue, age, and sex distribution of thallium in shrews from Doñana, a protected area in SW Spain

In 1998, the protected area of Do?ana, an important natural region in SW Europe, was affected with great amount of acidic waters and sludge from a pyrite mine loaded with toxic metals such as thallium (Tl). Since this ecological catastrophe, several studies have addressed the effects of this pollution on the flora and fauna in this protected area. However, in contrast to other non-essential metals, scarce information on Tl was available after this disaster, especially in terrestrial environments. This study reported a 3- and 10-fold increase in Tl in liver and kidneys, respectively, of the greater white-toothed shrew, Crocidura russula, in the polluted site in comparison with reference animals. Kidneys showed the highest concentrations of this metal in the polluted site, whereas both organs analysed have similar concentrations in the reference site. Although no significant age-dependent variation was found, adults had higher concentrations than juveniles. Moreover, females showed higher concentrations than males. These results demonstrate the high entrance and transfer of Tl in terrestrial food-chains. To the best of my knowledge, these data constitute the first measurements of Tl in mammals from the protected area of Do?ana and are among the few available for insectivorous mammals.     

Assessment of soil and groundwater impacts by treated urban wastewater reuse. A case study: application in a golf course (Girona, Spain)

Starting in July 2000, treated wastewater of urban origin has been used for the "Serres de Pals" golf course irrigation (Girona, Spain). To evaluate if the soil and the aquifer underneath are affected by the utilization of this type of water, samples have been taken along a period of several months from the wastewater treatment plant, the stabilization lagoon, groundwater and soil profiles. Analyses have been performed for total coliforms and aerobic bacteria, soil water pressure and soil water content as well as chemical analyses of the irrigation water, aquifer and water of the vadose zone. Soil profiles taken at several times during the study indicate the absence of coliforms except for a short period during summer. In the vadose zone an increase of more than 1000 mg kg(-1) of NaO(2) in the top 60 cm of soil was observed while Cl(-) concentration in the aquifer reached up to 1200 mg l(-1) ten months after starting the irrigation.     

How does the greater white-toothed shrew, Crocidura russula, responds to long-term heavy metal contamination? -- A case study

Heavy metals accumulation in parallel with the evaluation of physiological and biochemical effects resulting from continued metal exposure were considered here using for the first time the great white-toothed shrew Crocidura russula as an in vivo model. Shrews were originated from an abandoned lead/zinc mining area and from a reference area, both in Alentejo, southern Portugal. Hepatic contents of nickel, copper, zinc, cadmium, mercury and lead were quantified by Inductively Coupled Plasma Mass Spectrometer (ICP-MS). Haematological parameters (white blood cells, red blood cells, haemoglobin and haematocrit) were obtained in a Coulter Counter Analyser and biochemical markers of the redox balance (glutathione S-transferase, glutathione peroxidase, and glutathione reductase) activities were measured spectrophotometrically using a Duo-50 spectrophotometer. Compared with control animals, significantly higher concentration of hepatic cadmium (9.29 vs. 1.18 micorg/g dry weight) and nickel (1.56 vs. 0.343 microg/g dry weight) were detected in the shrews collected in the mining area. However, no significant changes were observed on haematological or enzymatic parameters in animals exposed to metal pollution. The obtained results show that shrews are good bioaccumulators of toxic heavy metals, but very tolerant to their effects, revealing an interesting long-term adaptation to polluted environments. In addition, this study provides reference values for haematological parameters and antioxidant enzymes levels in C. russula, which may be relevant for comparative purposes in further studies.     

Batch Stille Coupling with Insoluble and Recyclable Stannylated Polynorbornenes

The Stille coupling can be carried out in a batch process using insoluble tin supports. The new type of support consists of stannylated polymers based on the vinylic polynorbornene skeleton that allow one to use a set‐up where the tin reagent is immobilized in a column. The immobilized stannylated polymeric reagent can be easily reused. The coupling products are thus obtained by a very simple work‐up procedure and have very low levels of tin contamination.     

A novel kinetically-controlled de-pinning model for evaporating water microdroplets

A numerical investigation of neutrally hydrophobic water microdroplet evaporation on a flat, isothermal surface was conducted. The axisymmetric time-dependent governing equations of continuity, momentum, energy, and species were solved using FLUENT. The numerical model includes temperature- and species-dependent thermodynamic and transport properties. The explicit volume of fluid (VOF) model with dynamic meshing and variable-time stepping was utilized. The continuum surface force (CSF), the gravitational body force, and Schrage's molecular kinetic-based evaporation model were included in the governing equations. A novel approach was used to model de-pinning by using Blake's molecular kinetic-based contact line motion theory. Experimentally, droplet evaporation data was acquired with a standard dispensing/imaging system and high-speed photography. There is good agreement between the measured and predicted dimensionless droplet profile as characterized by the droplet volume (∀_d/∀₀), dynamic contact angle (θ/θ₀), contact radius (R/R₀), and apex height (H/H₀) when the de-pinned microdroplet numerical model is used. The de-pinning time (t_d) and volume (∀_d/∀₀) are controlled by both the de-pinning parameters (K_w and λ = n^− 2) and the accommodation coefficient (ε). On the other hand, the de-pinning contact angle (θ_d/θ₀) and height (H_d/H₀) are independent of ε.     

Numerical validation of a finite element thin‐walled beam model of a composite wind turbine blade

This paper presents a numerical validation of a thin‐walled beam (TWB) finite element (FE) model of a realistic wind turbine rotor blade. Based on the theory originally developed by Librescu et al. and later extended to suit FE modelling by Phuong, Lee and others, this computationally efficient yet accurate numerical model is capable of capturing most of the features found in large blades including thin‐walled hollow cross section with variable thickness along the section's contour, inner reinforcements, arbitrary material layup and non‐linear anisotropic fibre‐reinforced composites; the present application is, for the time being, restricted to linearity. This one‐dimensional (1D) FE model allows retaining information of different regions of the blade's shell and therefore approximates the behaviour of more complex three‐dimensional (3D) shell or solid FE models more accurately than typical 1D FE beam models. A 9.2 m rotor blade, previously reported in specialized literature, was chosen as a case study to validate the static and dynamic behaviour predicted by a TWB model against an industry‐standard 3D shell model built in a commercial software tool. Given the geometric and material complexities involved, an excellent agreement was found for static deformation curves, as well as a good prediction of the lowest frequency modes in terms of resonance frequencies, mode shapes and frequency response functions; the highest (sixth) frequency mode shows only a fair agreement as expected for an FE model. It is concluded that despite its simplicity, a TWB FE model is sufficiently accurate to serve as a design tool for the recursive analyses required during design and optimization stages of wind turbines using only readily available computational tools. Copyright © 2011 John Wiley & Sons, Ltd.