Detection of land animal remains in fish meals by the polymerase chain reaction-restriction fragment length polymorphism technique

In the present study a technique was developed with the aim of guaranteeing the composition and security of fish meals, since it allows verification of whether these meals contain land animal remains. The method is based on polymerase chain reaction (PCR) and length polymorphism, followed by a restriction fragment length polymorphism (RFLP). Specific primers for every species were designed and calibrated, generating exclusively a PCR product with a specific size when DNA for each species was present in the sample. This technique allows the detection of land animal remains in fish meals, specifically cow, chicken, pig, horse, sheep, and goat. The identity of the PCR products can be confirmed by RFLP analysis using only one restriction enzyme. The selected restrictase generated one characteristic restriction profile for every species included in this study. The detection limit of this method was calculated by using mixtures of fish meals in different proportions and meal that exclusively contained remains of one of these land species studied. The analytical strategy herein proposed was applied to fish and meat meals, giving good results, both in the analyzed standards and in commercial samples.     

Correlation of selected constituents with the total antioxidant capacity of coffee beverages: influence of the brewing procedure

Relationships between volatile and nonvolatile compounds and the antioxidant capacity of coffee brews prepared from commercial conventional and torrefacto roasted coffees, employing commonly used doses and prepared by four brewing procedures (filter, plunger, mocha, and espresso machine) were assessed. Significant correlations between volatile Maillard reaction products and antioxidant capacity (measured by both 2,2-diphenyl-1-picrylhydrazyl radical and redox potential methods) were not observed. Highly positive correlations between browned compounds and caffeine with both antioxidant capacity parameters were reported. Principal component analysis allowed coffee brews separation according to coffee roasting processes (PC1) and brewing procedures (PC2), showing that in all cases coffee brews from torrefacto roasted coffee were more antioxidant that those extracted from conventional ones; also, coffee brews extracted by an espresso machine were more antioxidant than those extracted by mocha, plunger, and filter machines.     

Antioxidant profile of red wines evaluated by total antioxidant capacity, scavenger activity, and biomarkers of oxidative stress methodologies

The study of the antioxidant capacity of foodstuffs requires the use of diverse determination methods to gain a wider picture of their multiple effects. The aim of this work was to evaluate the "antioxidant profile" of red wines applying TAC (total antioxidant capacity) methods: 2,2'-azinobis(3-ethyl-benzthiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl, N,N-dimethyl-p-phenylenediamine dihydrochloride, oxygen radical absorbance capacity, ferric reducing/antioxidant power, hydroxyl and superoxide radical scavenger activities, and biomarkers of oxidative stress methods such as lipid peroxidation inhibition and inhibition of damage to DNA. Furthermore, levels of total polyphenols (TPP) of wines were also evaluated. Three bottles of 107 different Spanish red wines (total samples 321), made from different grape varieties, aging processes, and vintages, were analyzed. The validation of TAC methods, the first step in this work, provided a good linearity, proportionality, and low detection limits. Among these methods, the ABTS was the most satisfactory for its rapidity, cost, and precision. All wines showed an important capacity to scavenge hydroxyl radicals and were capable of blocking superoxide radicals but with 10 times lower intensity. Wines also showed important protective action on biomarkers of oxidative stress; they were much more active to inhibit lipid peroxidation than DNA oxidation. Few statistically significant correlations among levels of TPP and antioxidant properties of wines were detected. Furthermore, values of these correlations were very low.     

D-amino acid formation in sterilized alkali-treated olives

The occurrence of d-amino acids in commercial ripe olives, a well-known sterilized alkali-treated product, was investigated by high-performance liquid chromatography (HPLC) with precolumn automatic derivatization. Absolute amounts of D-amino acids were in total 18.6-38.2 mg/100 g edible portion. The major D-amino acids were D-aspartic acid, D-glutamic acid, D-serine, and D-leucine. Furthermore, to evaluate the effects of sterilization time and olive pH on amino acid racemization, a simulated processing of green ripe olives was carried out. Serine (both free and bound form) was the most-racemized amino acid after heat treatment. Sterilization (15-35 min at 121 degrees C) increased the racemization values of both free and protein-bound amino acids, although in case of protein-bound phenylalanine the increase was not statistically significant. With an increase of pH from 8 to 10 units, the racemization values of all amino acids increased significantly, except for free forms of aspartic and glutamic acids. In general, the effects of the sterilization time and olive pH on total concentration (L + D enantiomers) of each amino acid were also significant.     

Effects of agricultural practices on color, carotenoids composition, and minerals contents of sweet peppers, cv. Almuden

Consumers demand organic products because they believe they are more flavorful and respectful to the environment and human health. The effects of conventional, integrated, and organic farming, grown in a controlled greenhouse, on color, minerals, and carotenoids of sweet pepper fruits ( Capsicum annuum), cv. Almuden, were studied. Experimental results proved that organic farming provided peppers with the highest (a) intensities of red and yellow colors, (b) contents of minerals, and (c) total carotenoids. Integrated fruits presented intermediate values of the quality parameters under study, and conventional fruits were those with the lowest values of minerals, carotenoids, and color intensity. As an example, the concentrations of total carotenoids were 3231, 2493, and 1829 mg kg (-1) for organic, integrated, and conventional sweet peppers, respectively. Finally, organic red peppers could be considered as those having the highest antioxidant activity of all studied peppers (agricultural farming and development stage).     

Fermentation as a bio-process to obtain functional soybean flours

The effect of fermentation on the antioxidant compounds [vitamins C and E, total phenolic compounds (TPC), and reduced glutathione (GSH)], and antioxidant capacity [superoxide anion scavenging activity (SOD-like activity), peroxyl radical-trapping capacity (PRTC), inhibition of phosphatidylcholine (PC) peroxidation, and Trolox equivalent antioxidant capacity (TEAC)] of soybean (Glycine max cv. Merit) was studied. Fermentation was carried out in solid state in cracked seeds inoculated with Aspergillus oryzae, Rhizopus oryzae, Bacillus subtilis, and Lactobacillus plantarum and in liquid state either in cracked seeds or milled soybean flours fermented naturally by only the microorganisms present in the seeds or by inoculation with L. plantarum. Vitamin C was not detected in the studied samples. Fermentation caused a decrease in vitamin E activity, except when cracked seed was fermented with A. oryzae, R. oryzae, or B. subtilis that increased 31, 30, and 89%, respectively. Fermentation produced an increase in TPC content and did not affect or reduce the GSH content. Fermentation decreased SOD-like activity drastically, while PRTC increased except when it was carried out naturally in cracked seed. TEAC values rose sharply when soybeans were fermented with B. subtilis. Processed soybean extracts inhibited PC peroxidation in comparison with the control assay. On the basis of the results obtained, the relative contributions of vitamin E, TPC, and GSH to antioxidant capacity were calculated and results showed a very high TPC contribution and a low contribution of GSH and vitamin E activity. Optimum results for functional soybean flours were achieved when fermentation was carried out with B. subtilis inoculum.     

Antioxidant capacity and phenolic content of grapes, sun-dried raisins, and golden raisins and their effect on ex vivo serum antioxidant capacity

Grapes and raisins provide phenolic antioxidants, which contribute to their potential health benefits. The objectives of this study were to compare the antioxidant capacity and phenolic content of green Thompson seedless grapes (the most common variety of grapes consumed in the United States), sun-dried raisins, and golden raisins (both produced from Thompson seedless grapes) and to observe the effects of their consumption over 4 weeks in 15 healthy human males with a cross-over design. The oxygen radical absorbance capacity (ORAC) (positive statistical significance for grapes after 2 weeks and golden raisins after 3 weeks), serum oxidation (positive statistical significance for golden raisin lag time after 4 weeks), total phenolics (no significant effects), and C-reactive protein (no significant effects) were monitored. Immediately postconsumption, there were some significant nonpositive changes. It is hypothesized that these negative results may be explained by postprandial oxidation, a known effect after carbohydrate consumption. Golden raisins had the highest antioxidant capacity and phenolic content. The consumption of a serving of grapes or raisins each day, in addition to a typical diet, may not be sufficient to overcome postprandial oxidation when consumed with other high carbohydrate foods but may have beneficial antioxidant effects over time.     

Titanium dioxide photoinduced degradation of some pesticide/fungicide precursors

Five-membered nitrogen heterocycles (pyrrole, imidazole and 1,2,4-triazole) have been degraded using titanium dioxide and simulated solar radiation at pH = 8. The degradations followed a simple Langmuir-Hinshelwood mechanism. Accordingly, the adsorption equilibrium constants K of the heterocycles on the titanium dioxide surface and the rate constants k of degradation of the heterocycle-catalyst adduct have been obtained experimentally. While the K values decrease with heterocycle pKa, the k values increase with increasing pKa. Therefore, apparently, the rate constant depends on the availability of the electron pair on nitrogen, but at the same time the electron pair repulsion induced by the negatively charged titanium dioxide surface at pH = 8 causes a reverse effect in the adsorption equilibrium constant. Only in the case of imidazole, where the adsorption equilibrium constant is low enough (K = 0.013 M(-1)), can the rate constant be approximated to a pseudo-first-order rate expression: k(obs) = Kk. In all other cases, k(obs) = Kk/(1 + K(heterocycle)).     

Permeability profile estimation of flavonoids and other phenolic compounds by biopartitioning micellar capillary chromatography

This paper points out the usefulness of biopartitioning micellar chromatography (BMC) using capillary columns as a high-throughput primary screening tool providing key information about the oral absorption, skin permeability, and brain-blood distribution coefficients of 15 polyphenols (6 flavones, 2 flavonols, a flavanone, 2 flavan-3-ols, 3 phenolic acids, and a phloroglucinol) in a simple and economical way. For the compounds studied, except vicenin-2, rutin, chlorogenic acid, p-hydroxycinnamic acid, and 4-hydroxybenzoic acid, maximal oral absorption (>90%) can be expected, if there are not solubility problems or metabolic processes. On the other hand, the most retained compounds in BMC, that is, 5-hydroxyflavone, flavone, and flavanone, show the highest brain-blood distribution coefficients and skin permeability coefficients.     

Beta-carotene isomer composition of sub- and supercritical carbon dioxide extracts. Antioxidant activity measurement

In the present work sub- and supercritical extraction conditions using carbon dioxide were studied in order to obtain extracts with different compositions from the green microalgae Dunaliella salina. Different compositions of beta-carotene isomers were identified in the extracts by using HPLC-DAD. Also, antioxidant activity of the extracts was measured using a TEAC assay. An experimental design was applied considering two factors, extraction pressure and temperature, in a wide range of values, trying to maximize the extraction yield. Higher yields were obtained at high pressures and low temperatures, that is, at higher CO2 densities. Attempts were made to correlate the antioxidant activity of the extracts with their chemical composition by means of principal component analysis. A certain relationship was found between their antioxidant activity and the isomeric composition of beta-carotenes. As a result, an original equation is proposed to predict the antioxidant activity of extracts from D. salina in terms of the ratio 9-cis-beta-carotene/all-trans-beta-carotene, the concentration of alpha-carotene, and, especially, the concentration of 9-cis-beta-carotene.