Effects of Fruit Position in Standard Place Pack Cartons and Gamma Irradiation on the Postharvest Quality of ‘Barnfield’ Navel Oranges

The objective of this study was to determine if oranges in the top and bottom layers within a Standard Place Pack were impacted differently by irradiation after long-term storage. ‘Barnfield’ Navel oranges were packed in Standard Place Pack cartons and treated with 0, 0.15, or 1 kGy of gamma irradiation. The fruit were stored for 3 weeks at 5 °C and then for 1 week at 20 °C. After storage, the fruit from the top and bottom layers were separately evaluated for quality. The development of stem-end rind breakdown (SERB) was the main cause of quality loss and was greater in irradiated fruit in the top layer. Fruit in the bottom layer showed more physical damage (flattening) but lower incidence of SERB. The changes in individual sugar content were minimal but significant for layer. The content of individual organic acids was consistently lower in irradiated fruit from the bottom layer. Layer type showed a stronger effect on phenolic compounds than irradiation dose. The tristimulus color, total soluble solids, titratable acidity, and firmness of fruit were not influenced by irradiation dose or layer type. The results show that damage in irradiated Navel oranges depends on dose and layer, with the top layers showing greater physiological damage and bottom layers showing more physical damage.     

Microstructural and photocatalytic characterization of cement-paste sol-gel synthesized titanium dioxide

A route for the in paste synthesis of TiO₂ loaded cement is described. TiO₂ sols are blended with fresh cement paste as an alternative process to add photocatalytic functionality to cement. The modification of cement paste structure after the addition of TiO₂ sols is analyzed by XRD, SEM and TGA. As a particular microstructural feature, TiO₂ containing calcium silicate hydrate (C-H-S) particles are identified as networking centers of a C-S-H gel fiber matrix. The increase of the TiO₂ sol concentration induces a decrease of pore size and an increase in the specific surface area in the cement composites. The photocatalytic activity of the TiO₂/cement system is evaluated from the degradation of Methylene Blue (MB) under UVirradiation, monitored through the absorbance at 665 nm. The results show that, although TiO₂ phases reveal no long range order structure, the cement paste exothermal treatment in presence of hydrate products and alkaline conditions leads to a photocatalytic composite. Such new cement matrix may be twofold advantageous since it additionally promotes the formation of C-S-H gel, main determinant of cement mechanical properties.     

Determination of cyprodinil and fludioxonil in the fermentative process of must by high‐performance liquid chromatography–diode array detection

BACKGROUND: A quantitative, selective and sensitive high‐performance liquid chromatographic method is described for the analysis of new fungicides cyprodinil, fludioxonil and their commercial formulation Switch in model solutions of must and wine, as well as samples during alcoholic fermentation. A study of the dissipation of residues was carried out. RESULTS: The proposed method is based on liquid–liquid extraction (LLE) followed by high‐performance liquid chromatography and diode array detection. Dichloromethane was the most appropriate solvent for extracting cyprodinil and fludioxonil in samples. Quality parameters of the proposed method presented good recovery (ca. 97% for almost all compounds) and precision (between 4.8% and 5.4%), and limits of quantification were lower than maximum residue limits (MRLs) in grapes. CONCLUSIONS: There is no matrix effect in the analysis of cyprodinil and fludioxonil. The application of the fermentative process on cyprodinil and fludioxonil fungicides causes a decrease in the concentrations of these compounds. This decrease is slightly higher, the higher the initial concentration, without observing the appearance of any product in degradation. Fludioxonil shows a higher reduction when the compounds are presented together in Switch. Copyright © 2008 Society of Chemical Industry     

Dietary compounds as modulators of metals and metalloids toxicity

A large part of the population is exposed to metals and metalloids through the diet. Most of the in vivo studies on its toxicokinetics and toxicity are conducted by means of exposure through drinking water or by intragastric or intraperitoneal administration of aqueous standards, and therefore they do not consider the effect of the food matrix on the exposure. Numerous studies show that some components of the diet can modulate the toxicity of these food contaminants, reducing their effect on a systemic level. Part of this protective role may be due to a reduction of intestinal absorption and subsequent tissue accumulation of the toxic element, although it may also be a consequence of their ability to counteract the toxicity directly by their antioxidant and/or anti-inflammatory activity, among other factors. The present review provides a compilation of existing information about the effect that certain components of the diet have on the toxicokinetics and toxicity of the metals and metalloids of greatest toxicological importance that are present in food (arsenic, cadmium, lead, and mercury), and of their most toxic chemical species.     

Physico-chemical properties and syngas production via dry reforming of methane over NiAl2O4 catalyst

Nano-particles of NiAl₂O₄ were prepared by co-precipitation and their bulk and surface were characterized by XRD, Raman spectroscopy, N₂-adsorption-desorption analysis, SEM-EDS and XPS. The reducibility was studied by TPR and HTXRD techniques under H₂ atmosphere. The synthetized catalyst was made of NiAl₂O₄ spinel oxide as main phase and of NiO (10%) free oxide. Interestingly, it was shown that the surface was richer in Al species. The catalytic performances in methane dry reforming were evaluated without H₂-pretreatment of catalyst. A very high activity was observed with conversion of methane and CO₂ at 750 °C of 84 and 90 mol%, respectively and high H₂/CO ratio. The amount of coke deposited during the reaction on this spinel was ～3.6%. The physico-chemical properties of the catalyst on their behavior in the dry reforming of methane are discussed.     

Surface functionalization and biomolecule immobilization using plasma-generated free radicals on polypropylene

In this study are presented evidences for the functionalization of polypropylene surfaces accomplished in a sequential process: argon- or oxygen-plasma enhanced generation of free radical sites on polypropylene surfaces was followed by “in situ” gas phase derivatization in the absence of plasma using ethylene diamine, or propylene diamine; and an “in situ”, gas phase derivatization using oxallyl chloride or “ex situ” derivatization in the presence of glutaraldehyde. The free radicals’ presence on the plasma-exposed polypropylene surfaces was confirmed using “in situ” sulfur dioxide or nitric oxide labeling techniques. It was shown that the free radical sites readily react under “in situ” conditions with the stable chain-precursor components and generate the desired spacer-chain molecules revealed by ESCA analysis. Functionalized polypropylene substrates were used for immobilization of α-chymotrypsin in the presence of spacer-chain molecules. The activity of the immobilized α-chymotrypsin was found to be comparable to the activity of the free enzyme when the spacer molecules have been used.     

A New Validated Real-Time PCR-Based Method for the Specific and Fast Detection of Cronobacter spp. in Infant Formula

In this study, a real-time polymerase chain reaction (PCR)-based method was designed for the fast detection of Cronobacter spp. (a newly proposed genus formerly known as Enterobacter sakazakii) in infant formula. The real-time PCR was positively tested with 70 Cronobacter strains, including members of all the species of this genus, and 88 non-Cronobacter strains. This new PCR-based system was validated against the reference standard ISO/TS 22964: 2006 (ISO International Organization for Standardization 2006) using 70 food matrices including powdered infant formula, follow-up formula, and hydrolyzed cereals for infants. The detection limit of the technique was found to be of 1 cfu in 10 g of food, fulfilling the requirements of the European Commission. The time of analysis, which comprises around 3–6 days using the reference method, is considerably reduced to less than 24 h using the real-time PCR-based system hereby described, allowing food industry a faster release of the stocks for commercialization. Moreover, this method includes an internal amplification control, co-amplified during each PCR run to verify the results.