Ion chromatographic determination of chloride in mustard sauces.

A new, simple, precise, and rapid ion chromatography (IC) method has been developed to determine chloride in mustard sauces using a mixture of phthalic acid, acetone, and water adjusted to pH 5.0 as eluent. Conductometric detection was carried out. The retention time for chloride was 1.5 min. Linearity was obtained up to a concentration level of 100 mg/L NaCl. The method was statistically evaluated for accuracy and precision after being used to assay the chloride from mustard sauces. Within the same samples, the chloride levels obtained by IC were compared with the sodium concentrations quantified by atomic absorption spectrophotometry.     

Enzyme-mediated solvent extraction of carotenoids from marigold flower (Tagetes erecta)

Marigold flowers are the most important source of carotenoids for application in the food industry. However, the extraction gives almost 50% losses of the carotenoids depending on conditions for silaging, drying, and solvent extraction. In the past decades, macerating enzymes have been successfully applied to improve the extraction yield of valued compounds from natural products. In this work, an alternative extraction process for carotenoids is proposed, consisting of a simultaneous enzymatic treatment and solvent extraction. The proposed process employs milled fresh flowers directly as raw material, eliminating the inefficient silage and drying operations as well as the generation of hard to deal with aqueous effluents present in traditional processes. The process developed was tested at the 80 L scale, where under optimal conditions a carotenoid recovery yield of 97% was obtained.     

Effects of pig slurry application on soils and soil humic acids

The effect of three annually consecutive additions of pig slurry at two rates (90 and 150 m3 x ha(-1) x year(-1) on soils and soil humic acids (HAs) was investigated in a field experiment under semiarid conditions. Soils and pig slurries were analyzed by standard methods. The HAs were isolated from soils and pig slurry by a conventional procedure based on alkaline extraction, acidic precipitation to pH 1, purification by repeated alkaline dissolutions and acidic precipitations, water washing, dialysis, and final freeze-drying. The HAs obtained were analyzed for elemental (C, H, N, S, and O) and acidic functional group (carboxylic and phenolic) composition, and by UV-vis, FT-IR, fluorescence, and ESR spectroscopies. With respect to the control soil, the pig slurry amended soils had greater pH and electrical conductivity, slightly larger total N content, and smaller values of C/N ratio. A decrease of total organic C was observed only in soils amended for 2 and 3 years at the higher slurry rate. With respect to control soil HA, pig slurry HA was characterized by larger contents of S- and N-containing groups, smaller acidic functional group and organic free radical contents, a prevalent aliphatic character, extended molecular heterogeneity, and smaller aromatic polycondensation and humification degrees. Amendment with pig slurry HA determines a number of modifications in soil HAs, including increase of C, S, and COOH contents, C/N ratios, and aliphaticity and decrease of extraction yields and N, O, phenolic OH, and organic free radical contents. These effects are generally more evident after the first year of slurry application and tend to disappear with increasing number of treatments. Most probably, over the years the slightly humified slurry HA is mineralized through extended microbial oxidation, whereas only the most recalcitrant components, such as S-containing, phenolic, and aliphatic structures, are partially accumulated by incorporation into soil HA.     

Migration studies to assess the safety in use of a new antioxidant active packaging

Both specific and overall migration tests have been applied to new experimental food packaging-active plastic films with antioxidant properties, including in its composition a natural rosemary extract. Determination of volatile and semivolatile compounds migrating from plastic to the four established simulants showed that both specific and overall migration was very low. The results obtained gave values 20 times lower than the established limits in the worst case. So, from the point of view of health risk, the new active packaging can be considered as safe. Analytical procedure used provided the necessary information about the migration behavior, with good analytical characteristics and detection limits in the sub mug kg(-1) range. Besides, no significant difference was found between laboratory and factory-made samples, which is an important issue for industrial production, the next step in the development of the new antioxidant active film.     

Antibacterial and antioxidant activities of essential oils isolated from Thymbra capitata L. (Cav.) andOriganum vulgare L

Antilisterial activities of Thymbra capitata and Origanum vulgare essential oils were tested against 41 strains of Listeria monocytogenes. The oil of T. capitata was mainly constituted by one component, carvacrol (79%), whereas for O. vulgare three components constituted 70% of the oil, namely, thymol (33%), gamma-terpinene (26%), and p-cymene (11%). T. capitata essential oil had a significantly higher antilisterial activity in comparison to O. vulgare oil and chloramphenicol. No significant differences in L. monocytogenes susceptibilities to the essential oils tested were registered. The minimum inhibitory concentration values of T. capitata essential oil and of carvacrol were quite similar, ranging between 0.05 and 0.2 microL/mL. Antioxidant activity was also tested, the essential oil of T. capitata showing significantly higher antioxidant activity than that of O. vulgare. Use of T. capitata and O. vulgare essential oils can constitute a powerful tool in the control of L. monocytogenes in food and other industries.     

Speciation of arsenic in different types of nuts by ion chromatography-inductively coupled plasma mass spectrometry

In this work the quantitative determination and analytical speciation of arsenic were undertaken in different types of nuts, randomly purchased from local markets. The hardness of the whole nuts and high lipid content made the preparation of this material difficult for analysis. The lack of sample homogeneity caused irreproducible results. To improve the precision of analysis, arsenic was determined separately in nut oil and in the defatted sample. The lipids were extracted from the ground sample with the two portions of a mixture of chloroform and methanol (2:1). The defatted material was dried and ground again, yielding a fine powder. The nut oil was obtained by combining the two organic extracts and by evaporating the solvents. The two nut fractions were microwave digested, and total arsenic was determined by inductively coupled plasma mass spectrometry (ICP-MS). The results obtained for oils from different types of nuts showed element concentration in the range 2.9-16.9 ng g(-)(1). Lower levels of arsenic were found in defatted material (<0.1 ng g(-)(1) with the exception of Brazil nuts purchased with and without shells, 3.0 and 2.8 ng g(-)(1) respectively). For speciation analysis of arsenic in nut oils, elemental species were extracted from 2 g of oil with 12 mL of chloroform/methanol (2:1) and 8 mL of deionized water. The aqueous layer, containing polar arsenic species, was evaporated and the residue dissolved and analyzed by ion chromatography-ICP-MS. The anion exchange chromatography enabled separation of As(III), dimethylarsinic acid (DMAs(V)), monomethylarsonic acid (MMAs(V)), and As(V) within 8 min. Several types of nuts were analyzed, including walnuts, Brazil nuts, almonds, cashews, pine nuts, peanuts, pistachio nuts, and sunflower seeds. The recovery for the speciation procedure was in the range 72.7-90.6%. The primary species found in the oil extracts were As(III) and As(V). The arsenic concentration levels in these two species were 0.7-12.7 and 0.5-4.3 ng g(-)(1), respectively. The contribution of As in DMAs(V) ranged from 0.1 +/- 0.1 ng g(-)(1) in walnuts to 1.3 +/- 0.3 ng g(-)(1) in pine nuts. MMAs(V) was not detected in almonds, peanuts, pine nuts, sunflower seeds, or walnuts, and the highest concentration was found in pistachio nuts (0.5 +/- 0.2 ng g(-)(1)).     

Analysis of virgin olive oil volatiles by a novel electronic nose based on a miniaturized SAW sensor array coupled with SPME enhanced headspace enrichment

A novel electronic nose based on solid-phase microextraction (SPME) coupled with a surface acoustic wave (SAW) sensor array has been used to analyze different quality virgin olive oils. A mathematical model was designed with 37 samples to distinguish lampante from the other virgin olive oils categories (extra-virgin and virgin), because lampante-virgin olive oils cannot be consumed without a previous refining process. The model, successfully validated with a test set of 16 samples, was able to classify 90% of the samples correctly. Misclassifications were explained by SPME-HRGC analyses and a second sensory evaluation.     

Effect of differently post-treated dewatered sewage sludge on β-glucosidase activity,microbial biomass carbon,basal respiration and carbohydrates contents of soils from limestone quarries

This work has evaluated the effects of thermally dried (TDS) or composted (CDS) dewatered sewage sludge on β-glucosidase activity, total (TCH) and extractable (ECH) carbohydrate content, microbial biomass carbon and basal respiration of soils from limestone quarries under laboratory conditions. Two doses (low and high) of the dewatered sludge (DS) or of the respective TDS or CDS were applied to a clayey and a sandy soil, both coming from working quarries. The soil mixtures and the controls (soils with no added sludge) were incubated for 9 months at 25°C and 30% of field capacity. The addition of sludge increased all the studied soil parameters, and the increase depended on the amount of sludge. Except in the case of TCH and ECH, the enhancing effect decreased with time, but at the end of incubation, parameters of the treated soils were higher than those of the control. The rank order of the initial stimulating effect was soil–TDS ≥ soil–DS ≥ soil–CDS, and probably, this order depended on the proportion of stable organic matter, which was the lowest in the TDS. Values of metabolic quotient (qCO₂) were higher at the lower dose, and they did not change during incubation in the CDS-treated soils. Both TCH and ECH were the parameters with the greatest significant sludge and dose effects. Basal respiration, microbial biomass carbon and β-glucosidase activity were the best measured parameters in distinguishing the long-term effects of the three sludge types over the soils.     

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.     

Chemical markers for the evaluation of raw material hygienic quality in egg products

The aim of this research was to study uracil and lactic and acetic acids as chemical markers for hygienic quality evaluation of raw material in liquid pasteurized egg products. Uracil, absent in sound whole eggs, was formed in raw and pasteurized egg products as a consequence of high microbial contamination (>10(6) cfu/g) after a sufficient lag time, remaining stable at 4 degrees C but disappearing after 7 days of storage at 25 degrees C. Both lactic and acetic acids, starting from initial values of 1-7 mg/kg dry matter, presented trends similar to that of uracil; however, acetic acid never decreased during the storage of raw egg products. With few exceptions, all three metabolites were produced by Enterobacter cloacae, Escherichia coli, Morganella morganii, Serratia liquefaciens, Aeromonas hydrophyla, Pseudomonas fluorescens, Enterococcus avium, and Enterococcus faecalis, separately inoculated in whole egg samples. Uracil seems to be the most sensible marker, with a suggested limit corresponding to the detectable level.