Polyphenol oxidase activity,phenolic acid composition and browning in cashew apple (Anacardium occidentale, L.) after processing

This study describes the extraction and characterisation of cashew apple polyphenol oxidase (PPO) and the effect of wounding on cashew apple phenolic acid composition, PPO activity and fruit browning. Purification factor was 59 at 95% (NH₄)₂SO₄ saturation. For PPO activity, the optimal substrate was catechol and the optimum pH was 6.5. PPO K_m and V_max values were 18.8 mM and 13.6 U min⁻¹ ml⁻¹, respectively. Ascorbic acid, citric acid, sodium sulphite and sodium metabisulphite decreased PPO activity, while sodium chloride increased PPO activity. Wounding at 2 °C and 27 °C for 24 h increased PPO activity but storage at 40 °C reduced PPO activity. Gallic acid, protocatechuic acid and cinnamic acid (free and conjugate) were identified in cashew apple juice. Cutting and subsequent storage at 40 °C hydrolysed cinnamic acid. 5-Hydroxymethylfurfural content in cashew apple juice increased after injury and storage at higher temperatures, indicating non-enzymatic browning.     

In vivo antitumoural activity and composition of an oil extract of Brazilian propolis

The present study aimed to evaluate in vivo and in vitro the antitumoural activity of a propolis extract obtained with edible vegetable oil and its fractions and also to investigate its chemical composition by LC–MS and LC–MS/MS. To evaluate the toxicological aspects related to the propolis extract treatment, hematological, biochemical, histopathological and morphological analyses of treated animals were performed. All propolis extracts showed an in vivo antitumour activity in the experimental model with a moderate toxicity effect at experimental exposure levels. The oil extract was as effective as the ethanolic extract at inhibiting tumour growth. In vitro assays showed that the whole oil extract produced better inhibition of tumour cells than its fractions. LC–MS and LC–MS/MS identified four phenolic acids and three flavonoids. The anticancer potential of the oil extract of propolis has been demonstrated and the edible vegetable oil was shown as an attractive alternative solvent to extract bioactive natural propolis components.     

Flexible power generation scenarios for biogas plants operated in Germany: impacts on economic viability and GHG emissions

Biogas plants enable power to be generated in a flexible way so that variable, renewable energy sources can be integrated into the energy system. In Germany, the Renewable Energy Sources Act promotes flexible power generation in biogas plants. Two existing biogas plants in flexible operation were analyzed with respect to economic viability and greenhouse gas (GHG) emissions to assess the feasibility of flexible operation. To do this, a biogas technology simulation model was developed to reproduce the technical design of both biogas plants and to link this design with twelve flexibilization scenarios. The evaluation of the economic viability is based on a discounting method of investment appraisal. For assessing the level of GHG emissions, the life cycle assessment method has been applied. The results show that the profitability of flexibilization is contingent upon premium payments promoting flexibility and direct sales resulting from a higher electrical efficiency of new or additionally installed combined heat and power units. Overall, with respect to profitability, the results of the flexible power generation scenarios are dependent upon the properties of the technical plant, such as its power generation and gas storage capacities. Relative GHG emissions from flexible biogas plants show significantly lower values than for referenced fossil gas–steam power stations. Among the various scenarios, the results reveal that the level of GHG emissions especially depends on the number of operating hours of the additional combined heat and power unit(s). The results of the analyzed biogas plants showed no direct correlation between GHG emissions and the economic benefits. Overall, a flexible power generation of biogas plants may improve the economic viability as well as result in lower GHG emissions in comparison with a conventional base load operation. © 2016 The Authors. International Journal of Energy Research published by John Wiley & Sons Ltd.     

Influence of pressure losses on compressor performance in a pressurized fuel cell air supply system for airplane applications

Low ambient pressures at elevated flight altitudes lead to power losses in fuel cell powered aircrafts. As countermeasure ambient air can be pressurized with a suitable fuel cell air supply system. In this study the influence of low ambient pressures and pressure losses within the system on the performance of two turbo compressors and the resulting stack power are examined theoretically and the findings validated experimentally. Results show that decreasing ambient pressures and pressure losses in front and after the compressor reduce the maximum pressure from 2.4 to 1.6 bar(a) in the examined system. Air compression may require a significant share of the fuel cell stack power and the maximum system power is reduced from 54 to 41 kW. For air pressures higher than 1.8 bar(a) the fuel cell stack power gain due to pressurization is found to be cancelled out by the increasing power required for air compression.     

Comparison of two atmospheric correction methods for the classification of spaceborne urban hyperspectral data depending on the spatial resolution

For remote-sensing applications such as spectra classification or identification, atmospheric correction constitutes a very important pre-processing step, especially in complex urban environments where a lot of phenomenons alter the shape of the signal. The objective of this article is to compare the efficiency of two atmospheric correction algorithms, COCHISE (atmospheric COrrection Code for Hyperspectral Images of remote-sensing SEnsors) and an empirical method, on hyperspectral data and for classification applications. Classification is carried out on several simulated spaceborne data sets with different spatial resolutions (from 1.6 to 9.6 m). Four classifiers are considered in the study: a k-means, a Support Vector Machine (SVM), and a sun/shadow version of each of them, which processes sunlit and shadowed pixels separately. Results show that the most relevant atmospheric method for classification depends on the spatial resolution of the processed data set. Indeed, if the empirical method performs better on high-resolution data sets (up to 4%), its superiority fades out as the spatial resolution decreases, especially with the lower spatial resolution where COCHISE can be 10% more accurate than the empirical method.     

Dietary fat in the prevention of cardiovascular disease — a review

In developed countries atherosclerotic cardiovascular disease is the reason for about 50% of all deaths. With growing prosperity coronary heart disease (CHD) is becoming the major cause of premature death. Most complications of atherosclerosis occur unexpectedly and more than 50% of the patients developing a myocardial infarction do not survive more than one year. Because of the severe morbidity and high mortality primary prevention is likely to be the only solution. Epidemiological studies show a strong, positive relationship between plasma cholesterol concentrations and the incidence of CHD. People who immigrate from low‐risk to high‐risk areas usually acquire similar plasma cholesterol levels as the native population and a similar CHD risk. This demonstrates that environmental rather than genetic factors lead to the differences in cardiovascular risk and supports the notion that nutrition and lifestyle play a major role. The association between dietary intake of fat and cholesterol and the extent of atherosclerosis and CHD has been recognized in previous studies. The amount of saturated fat in the diet correlates stronger with the incidence of CHD than with total fat intake. The consumption of unsaturated fatty acids, however, appears to be beneficial, since it is inversely correlated with the plasma cholesterol concentration and risk of myocardial infarction. Lately additional nutritional factors like trans fatty acids with a negative influence on risk as well as positive factors like linolenic acid have attracted much attention. In conclusion, as a challenge to public health, preventive medicine needs to focus on changes in dietary habits with priority, particularly fat modification. A nutrition low in total fat primarily avoiding saturated and trans fatty acids, but rich in fruit and vegetables should be recommended.     

Limited-Dose Electron Microscopy Reveals the Crystallinity of Fibrous C–S–H Phases

Using electron diffraction, we demonstrate that the fibrous calcium–silicate–hydrates (C–S–H) of tricalciumsilicate (C₃S) hydration possess a crystalline structure. The crystalline nature was revealed by limiting the electron dose, which is common in electron microscopy of biomacromolecules. Compared with room temperature, the fading of the electron diffraction patterns at −175°C occurs at an electron dose that is about one order of magnitude higher. A combination of low-dose and cryo-protection methods offers the possibility to investigate the structures of water-containing cement phases by high-resolution electron microscopy in a close-to-native state.