Occurrence of ochratoxin A-producing fungi in raw Brazilian coffee

Ochratoxin A (OA)-producing fungi were identified in coffee at different stages of maturation. The toxin was quantified in coffee during terrace drying and in coffee stored in barns. By direct plating, a high level of contamination (100%) was found in the coffee beans studied, with the genus Aspergillus representing 33.2%, of which Aspergillus ochraceus and Aspergillus niger represented 10.3 and 22.9%, respectively, of the strains isolated from the coffee beans. The capacity to produce ochratoxin was determined in 155 strains of A. ochraceus and A. niger using both the agar plug method and extraction with chloroform, giving positive results for 88.1% of the A. ochraceus strains and 11.5% of the A. niger strains. Analysis for OA in the terrace and barn coffee samples showed that, independent of cultivar, year harvested, or production region, all except one of the samples analyzed showed mycotoxin levels below the limit suggested by the European Common Market (8 microg/kg), thus indicating that the problem is restricted and due to severe faults in harvesting and storage practices.     

Assisted navigation for a brain-actuated intelligent wheelchair

This paper presents an Assistive Navigation System (ANS) for a Robotic Wheelchair (RW) relying on a Brain–Computer Interface (BCI), as the Human–Machine Interface (HMI). A two-layer collaborative control approach is proposed to steer the RW, taking into account both user and machine commands. The first layer, a virtual-constraint layer, is responsible for enabling/disabling the user commands, based on context. More specifically, user commands are enabled for a set of situations requiring user decision, namely, bifurcations, multiple-directions caused by new obstacles in the environment, and deadlocks. The second layer is a user-intent matching responsible for determining the suitable steering command that better fits the user selection, taking into account the user competence to steer the wheelchair, and situation awareness of potential directions at a given location. A P300-based BCI allows the selection of commands to steer the RW. Experimental results using RobChair (Pires and Nunes (2002) [7], Lopes et al. (2007) [42]) are presented, showing the effectiveness of the proposed methodologies. The ANS was validated with ten able-bodied participants, and one participant with cerebral palsy, in two different scenarios: a structured known environment, and a structured unknown environment with moving objects. The overall result was that all participants were able to successfully operate the device, showing a high level of robustness of both, the BCI system, and the navigation system.     

Gas-phase hydrogen-transfer reduction of acrolein using 2-propanol over MgO/B2O3 and SiO2/AlPO4 catalysts

Two MgO/B2O3 and SiO2/AlPO4 catalysts designated BM50 and PM2, respectively, were used in the gas-phase hydrogen transfer between acrolein and 2-propanol to obtain allyl alcohol and propanal. The acid-base properties and catalytic activity of the two systems were found to be rather different. Thus, the MgO/B2O3 catalyst is more selective towards allyl alcohol than is the SiO2/ AlPO4 catalyst (conversion to the alcohol was 28% with the former and 0% with the latter). This special selectivity is discussed in terms of the different ways in which acrolein can be adsorbed on the catalytic surface as revealed by temperature-programmed desorption profiles and DRIFT spectra for pre-adsorbed acrolein. This revised version was published online in July 2006 with corrections to the Cover Date.     

Acceptability of partially dealcoholized wines – Measuring the impact of sensory and information cues on overall liking in real-life settings

In this study, the effect of partial alcohol reduction in wine on consumer expectation and overall liking was investigated in real-life settings (by a Home-Use-Test). By varying the wine in the bottle and by manipulating the information on the label, it was possible to assess the relative impact of sensory properties and information cues on overall liking.Standard Chardonnay and Syrah wines were partially dealcoholized from about 13.5% to about 9.5%. After bottling, these dealcoholized wines were presented once with information about real alcohol content (9.5%) and once with false information about alcohol content (13.5%). A third bottle with standard wine inside was also presented with real information about alcohol content (13.5%). A group of 194 French wine consumers rated the three wines at home for liking before and after tasting on continuous hedonic scales. Another group of 90 French wine consumers evaluated the wines at the laboratory.The same order of preference was obtained in both laboratory and home conditions but wines generally attained significantly higher hedonic scores in Home-Use-Tests. A strong segmentation of consumers highlighted specific consumer behaviors regarding expectation and overall liking of wines. Results emphasized the importance of both sensory and information cues in the development of overall liking by consumers.     

Effect of treatment with α‐galactosidase,tannase or a cell‐wall‐degrading enzyme complex on the nutritive utilisation of protein and carbohydrates from pea (Pisum sativum L.) flour

The effect of treatment with α‐galactosidase, tannase or a cell‐wall‐degrading enzyme complex under optimal conditions of pH, temperature and length of incubation time on the chemical composition and nutritive utilisation of protein and carbohydrates from pea (Pisum sativum L.) flour was studied. Soaking of pea flours in combination with enzyme treatment led to reductions of 77–90% in the levels of α‐galactosides, and of 60–80% in the levels of trypsin inhibitor activity, increasing the content of total available sugars, which was highest in the pea flour treated with the cell‐wall‐degrading enzyme complex. All the treatments assayed caused a significant improvement in daily food intake, whereas the nutritive utilisation of protein was not increased in any of the pea products tested when compared to the raw pea flour. However, all the soaking and enzymatic treatments led to a significant improvement in daily weight gain associated with a higher dietary intake of food and total available sugars. Copyright © 2007 Society of Chemical Industry     

Effect of phytic acid degradation by soaking and exogenous phytase on the bioavailability of magnesium and zinc from Pisum sativum, L.

The effect of dephytinization of Pisum sativum, L. flour on the bioavailability of Mg and Zn was evaluated in growing rats. Processing of legume flours under optimal conditions for phytase activity (pH 5.5, 37 °C, 60 min) and subsequent removal of the soaking solution led to a 42 and 61% reduction in the content of Mg and Zn, respectively. Treatment with phytase led to an additional reduction in the concentration of the above-mentioned seed flour components, compared to the raw pea flour (69% and 74% for Mg and Zn, respectively). The considerable reduction in the content of inositol phosphates with high degree of phosphorylation attained under both processing conditions did not affect the digestive utilization of Mg, whereas the metabolic utilization of this mineral increased significantly. The digestive and metabolic utilization of Zn increased significantly in response to both processes assayed, reaching the highest values in the experimental group that was fed the phytase-treated pea flour diet. The amount of Mg retained by the experimental animals was reflected in the content of this mineral in the different tissues studied (femur, sternum, kidney, and heart), whereas no correlation was found in the case of Zn.     

Catalytic use of zeolites in the Prins reaction of arylalkenes

The Prins reaction of various arylalkenes with paraformaldehyde on different zeolites as solid acid catalysts was studied. The main product of the reaction under the experimental conditions used was found to be the corresponding 1,3-dioxane. Of the catalysts tested, beta (75) zeolite proved the most active and selective in the Prins reaction of styrene, with a selectivity of 41.4% and a conversion of 95%. Other zeolites such as USY and, especially, ZSM-5, provided much lower yields. The reactions of other arylalkenes were found to be strongly influenced by the substituents on the double bond.