Biocatalytic nylon nanofibrous membranes.

Nylon-6 nanofibrous membranes (NFM) have been prepared, characterized and used to build-up electrochemical biosensing devices. The assembly and the functioning of biocatalytic NFM are described in connection with the physical and the covalent immobilization of glucose oxidase for the detection of glucose. Effects of the enzyme loading, the mediator, the pH, the surface acidity and the kinetic of the catalysis have been thoroughly investigated. The results show that NFM allow the binding of proteins without the need for the hydrolysis step, in contrast to the nylon film. Furthermore, the high surface-to-volume ratio of the NFM allow superior loading of the enzyme with respect to thin film technology. The immobilization step does not affect the permeability of the coating to the mediator used. These results give evidence that NFM are a promising and inexpensive coating for a novel electrochemical transducer.

Antioxidant characterization of some Sicilian edible wild greens.

Epidemiological studies have demonstrated that many antioxidants and the total antioxidant capacity (TAC) of the diet may protect against cancers and cardiovascular disease. Common fruits and vegetables are good sources of antioxidants, although in some Mediterranean areas traditional wild greens are responsible for a significant percentage of total dietary antioxidant intake. In the European Prospective Investigation into Cancer and Nutrition cohort of Ragusa (Sicily), a high number of subjects were found to frequently eat wild greens, including Sinapis incana and Sinapis nigra, Diplotaxis erucoides, Cichorium intybus, Asparagus acutifolius, and Borrago officinalis. On the basis of these observations, detailed characterization of single antioxidant components (i.e., polyphenols, carotenoids, chlorophylls, and ascorbic acid) and the TAC of these edible wild traditional plants was performed. The wild plants examined were found to be very rich in antioxidants, such as flavonoids and carotenoids, with high TAC values, suggesting that the importance of these vegetables, not only in the traditional but even in the contemporary diet, needs to be emphasized.

Application of near-infrared reflectance spectroscopy (NIRS) to the evaluation of carotenoids content in maize.

The importance of including antioxidant compounds in the diet is well recognized. These compounds remediate the detrimental activity on animal cells of the so-called reactive oxygen substances (ROS). Many papers have reported on the determination of both hydrophilic and hydrophobic antioxidant compounds present in a large number of vegetables, and all methods involve the extraction from the matrix of the compounds to be determined. Because some problems may arise, such as the completeness of the extraction and the stability of the extracted compound during the extraction steps, the possibility of analyzing these compounds in the native matrix would be useful. Here is reported the application of near-infrared spectroscopy (NIRS) to the determination of the content of carotenoids in maize, comparing the obtained data with those derived from high-performance liquid chromatography (HPLC) determination of the extract obtained from the same samples. Equations for predicting carotenoid content in maize were derived using scores from modified partial least-squares (MPLS) as independent variables. Cross-validation procedures indicated good correlations between HPLC values and NIRS estimates. The results show that NIRS, a well-established and widely applied technique, can be applied to determine the maize carotenoids and that samples are readily analyzed in minutes, the only required step being their grinding.

Presence of allergenic proteins in different peach (Prunus persica) cultivars and dependence of their content on fruit ripening.

It has been reported that various cultivars of fruits and vegetables may present a different pattern for the contained allergens. Here, we report on the different content in allergenic proteins for different peach (Prunus persica) cultivars, sampled during two consecutive harvest seasons. Fruits from six cultivars of peaches were harvested fully ripe, and the proteins extracted from whole or chemically peeled fruits were analyzed by SDS-PAGE and immunoblotting. All the protein extracts from whole fruit contained a 9 kDa protein. This protein proved to be absent in the extracts taken from chemically peeled fruit. In four cultivars, this protein corresponds to the allergen Pru p3, a lipid transfer protein that causes the oral allergy syndrome (OAS) in sensitized people. In the following year, fruits from four of the six cultivars of peaches studied previously were harvested at different times, at one and two weeks before the commercial ripening time and when fully ripe, to ascertain whether the presence of the 9 kDa allergen might be related to the ripening process. Two cultivars out of four produced an intense allergenic band corresponding to a 9 kDa protein already two weeks before the commercial ripening date, while the others showed a progressive increment of the 9 kDa allergen during ripening.

Experimental studies to obtain rice malt.

The production of a rice malt that could be used as an ingredient in gluten-free foodstuffs, especially for brewing purposes, was studied. Different rice varieties were characterized through morphological description and chemical-physical analyses. Each rice variety was germinated in the laboratory in jute bags for different periods. To produce a rice malt with a good diastatic power, steeping and airing conditions, as well as time and temperature during germination, were studied. The endogenous enzymatic activities, which developed during the malting process and which characterize the diastatic power of the obtained rice malts, were also measured. The conditions of the malting process and the drying step were checked and optimized to produce rice malt with the desired color and aroma. Once the most efficient malting procedure had been chosen, the most suitable rice variety underwent the germination and kilning process in a pilot plant. Some saccharification tests were performed in the laboratory to verify the sugar content of worts obtained from the produced rice malts and whether they could be successfully fermented. The results showed that a good rice malt could be obtained, even if it has a lower enzymatic activity than barley malt.

Tomato allergy: detection of IgE-binding lipid transfer proteins in tomato derivatives and in fresh tomato peel, pulp, and seeds.

There is an increasing consumption of tomatoes worldwide: fresh in salads, cooked in household sauces, or industrially processed. Although many tomato allergens have been identified, there is no information in the literature on the allergenic components found in commercial tomato products. The primary aim of the study was to evaluate the allergenic profile of commercial tomato products by skin prick tests (SPTs) and IgE/immunoblotting in tomato-allergic subjects. The secondary end point was the study of the IgE-binding profile of tomato peel, pulp, and seeds. Forty tomato-allergic patients, reporting oral allergy syndrome (OAS) at different grades of severity for fresh and, in some cases, also for cooked tomato, were selected on the basis of positive tomato allergy history or open food challenge (OFC). They were evaluated by SPTs with different experimental tomato extracts. SDS-PAGE/immunoblotting was performed to detect tomato allergens, which were then identified by Edman degradation. Twenty-three patients (57.5%) presented first-grade OAS at the OFC, whereas 17 (42.5%) reported severe symptoms. Ten of these 17 patients (25%) reported allergic reactions to cooked tomatoes; in immunoblotting tests, their sera reacted only to lipid transfer protein (LTP). In commercial products, LTP was the only detectable allergen. In contrast to other LTP-containing fruits, in tomato, an IgE-binding LTP was identified not only in the peel but also in the pulp and seeds. This study demonstrates that, in fresh tomato, different LTP isoforms are present and allergenic. Industrial tomato derivatives still contain LTP, thus presenting a problem for LTP-allergic patients.