Accurate determination of 2,4,6-trichloroanisole in wines at low parts per trillion by solid-phase microextraction followed by GC-ECD

A headspace solid-phase microextraction (HS-SPME) procedure at 30 degrees C with a 100 microm PDMS fiber of a saturated NaCl solution stirred at 1100 rpm combined to GC-ECD for the 2,4,6-trichloroanisol (TCA) determination in wines has been developed. Due to the matrix complexity and ethanol absorption into the fiber, the internal standard selection was crucial to obtain unbiased results. Thus, matrix effects were observed when analyzing different types of Spanish wines (white, early, and vintage red wines) spiked with TCA at low concentration levels (i.e., <40 ng L(-)(1)). In contrast, the use of 2,4,6-tribromoanisole (TBA) as internal standard overcame these matrix effects, whereas the use of 2,4,6-trichlorophenyl ethyl ether led to inconsistent results. The developed HS-SPME-GC-ECD methodology reaches a limit of quantitation for TCA in wine within 2.9-18 ng L(-)(1), with a relative standard deviation of 2.5-13.4%, depending on the TCA concentration level and wine characteristics. This analytical method is comparable to the existing methodologies based on HS-SPME followed by GC-MS in terms of accuracy, precision, length of determination, and length of quantification; however, analysis cost is reduced.     

Identification and quantification of carotenoids including geometrical isomers in fruit and vegetable juices by liquid chromatography with ultraviolet-diode array detection

A method was established for the identification and quantification of carotenoids including geometrical isomers in fruit and vegetable juices by liquid chromatography with an ultraviolet-diode array detector, using a C(18) Vydac 201TP54 column. The mobile phase used was the ternary methanol mixture (0.1 M ammonium acetate), tert-butyl methyl ether and water, in a concentration gradient, and a temperature gradient was applied. Retinol palmitate was added as an internal standard. An extraction process (ethanol/hexane, 4:3, v/v) was performed, followed by saponification with diethyl ether/methanolic KOH (0.1%, w/v, BHT) (1:1, v/v) for 0.5 h at room temperature. Seventeen different (cis and trans) carotenoids were identified by UV-vis spectra and retention times in HPLC in the juices analyzed. The analytic parameters show that the method proposed is sensitive, reliable, accurate, and reproducible.     

Changes in broccoli (Brassica oleracea L. Var. italica) health-promoting compounds with inflorescence development

Changes in phenolic compounds, total glucosinolates, and vitamin C were monitored during the productive period along five inflorescence development stages of three broccoli commercial cultivars (Marathon, Monterrey, and Vencedor). In an attempt to identify differences due to agronomic factors, broccoli cultivars were grown under different sulfur fertilization with poor (15 kg/ha) and rich (150 kg/ha) rates. Phenolic compounds and vitamin C concentrations showed, in all broccoli cultivars, a rising trend from the first stage until the over-maturity stage, both for rich and poor sulfur fertilization. Significant differences were detected in the first two stages between rich and poor sulfur fertilization in total glucosinolates for all broccoli cultivars, where the highest concentration was always observed in the second development stage (used as minimally processed product) during poor fertilization. With regard to the last three stages, the glucosinolate concentration in the poor sulfur fertilization started to slope down until the over-maturity stage. Where rich sulfur fertilization is concerned, the highest level was reached during the third stage (used as minimally processed product also), and after that, glucosinolate concentration decreased until the fifth stage.     

Changes in photosynthesis and antioxidant metabolism of cotton (Gossypium hirsutum L.) plants in response to manganese stress

ABSTRACT

This study aimed to assess the physiological and biochemical responses of cotton plants to manganese (Mn²⁺) nutrition. Four cotton genotypes (G1 – TMG 47; G2 – FM 975 WS; G3 – TMG 11 WS and G4 – IMA 8405 GLT) were grown in nutrient solution under two Mn²⁺ concentrations (2 and 200 µmol L^?1) for 10 days. No visible symptoms of Mn²⁺ toxicity were observed in the genotypes tested. All genotypes showed a marked increase in leaf chlorophylls, pheophytins, carotenoids, sucrose and total sugars concentration in response to high Mn²⁺ in a nutrient solution. However, the net photosynthetic rate, stomatal conductance, internal carbon dioxide concentration and transpiration decreased in genotypes G1 and G2 growing under 200 µmol L^?1. Antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR) activities increased in genotypes G1, G3 and G4. Cotton genotypes showed an increased leaf antioxidant and sugar metabolism as a possible strategy to mitigate oxidative stress. The decrease in the net photosynthetic rate and stomatal conductance; the increased antioxidant enzymes activities (SOD, APX and GR); and the increase in leaf sucrose and total sugar concentration were the main physiological and biochemical responses in cotton plants to Mn²⁺ stress.     

Growth and Nutritional Disorders of Eggplant Cultivated in Nutrients Solutions with Suppressed Macronutrients

The objective was to evaluate the effects of omitting macronutrients in the nutrients solution on growth characteristics and nutritional status of eggplants. The treatments were complete nutrients solution and solutions with nutrient omission: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S). The experiment was carried out under greenhouse conditions with three replicates in a completely random design. Plant height, number of leaves per plant, leaf area, relative chlorophyll index, photosynthesis rate, stomatal conductance, dry matter, concentration levels of macronutrients in plant aerial part and root system, and nutritional disorders were evaluated. Omitting elements interfered in the concentration of elements in the various plant tissues and this had as consequences limited vegetative growth, reduced dry matter and led to the development of the typical deficiency symptoms of each element. Although potassium was the most demanded of all elements, nitrogen and calcium were the most growth limiting ones.     

Characterization and quantitation of phenolic compounds in new apricot (Prunus armeniaca L.) varieties

Thirty-seven apricot varieties, including four new releases (Rojo Pasión, Murciana, Selene, and Dorada) obtained from different crosses between apricot varieties and three traditional Spanish cultivars (Currot, Mauricio, and Búlida), were separated according to flesh color into four groups: white, yellow, light orange, and orange (mean hue angles in flesh were 88.1, 85.0, 77.6, and 72.4, respectively). Four phenolic compound groups, procyanidins, hydroxycinnamic acid derivatives, flavonols, and anthocyanins, were identified by HPLC-MS/MS and individually quantified using HPLC-DAD. Chlorogenic and neochlorogenic acids, procyanidins B1, B2, and B4, and some procyanidin trimers, quercetin 3-rutinoside, kaempferol 3-rhamnosyl-hexoside and quercetin 3-acetyl-hexoside, cyanidin 3-rutinoside, and 3-glucoside, were detected and quantified in the skin and flesh of the different cultivars. The total phenolics content, quantified as the addition of the individual compounds quantified by HPLC, ranged between 32.6 and 160.0 mg 100 g(-1) of edible tissue. No correlation between the flesh color and the phenolic content of the different cultivars was observed.     

Relationship between virgin olive oil phenolic compounds and acrylamide formation in fried crisps

In this paper the relationship between virgin olive oil (VOO) phenol compounds and the formation of acrylamide in potato crisps was investigated. The phenol compositions of 20 VOO samples were screened by LC-MS, and 4 oils, characterized by different phenol compound patterns, were selected for frying experiments. Slices of potatoes were fried at 180 degrees C for 5, 10, and 15 min, and acrylamide content was determined by LC-MS. Results demonstrated that VOO phenolic compounds are not degraded during frying, and crisp color was not significantly different among the four VOOs. Acrylamide concentration in crisps increased during frying time, but the formation was faster in the oil having the lowest concentration of phenolic compounds. Moreover, the VOO having the highest concentration of ortho-diphenolic compounds is able to efficiently inhibit acrylamide formation in crisps from mild to moderate frying conditions. It was concluded that the use of ortho-diphenolic-rich VOOs can be proposed as a reliable mitigation strategy to reduce acrylamide formation in domestic deep-frying.     

Effect of dietary protein source and time on alkaline proteolytic activity of Nile tilapia (<Emphasis Type="Italic">Oreochromis niloticus</Emphasis>)

A 4 × 3 factorial study was conducted to evaluate the effect of four experimental diets (a control diet and a 0, 50, and 100% fish meal replacement diet) and the period of time Nile tilapia, Oreochromis niloticus, were fed those diets (0, 20, and 40 days) on the alkaline proteolytic activity of the animals’ digestive tract, as well as their potential interaction. Significant differences (at P < 0.05) and a significant interaction were observed among dietary treatments for the alkaline proteolytic activity of tilapia after 40 days of feeding. This study confirmed that, under these experimental conditions, a 50% fish meal replacement formulation elicited the highest alkaline proteolytic activity in the digestive tract of tilapia, which resulted in the highest final weight and specific growth rate (SGR), but further research is needed to establish the relative contribution of the alkaline proteases to the overall proteolytic activity of this omnivorous fish species.     

Impact of aquaculture on mangrove areas in the northern Pernambuco Coast (Brazil) using remote sensing and geographic information system

The conversion of mangrove areas into shrimp farming ponds has been indicated as the main activity responsible for the reduction in the area of this ecosystem along the northeastern coast of Brazil. The present study was conducted using remote sensing methods and a geographical information system with the aim of quantifying the participation of this activity in the reduction of the mangrove areas along the northern coast of the State of Pernambuco (northeast, Brazil), where shrimp farming has been implanted in last recent years. From 1973 to 2005, there was reduction of about 2.052 ha of mangrove, 197 ha of which were converted into shrimp ponds. Thus, the real contribution of shrimp farming to this reduction was just 9.6% of the total area. Other anthropogenic activities, such as agriculture, urban expansion and tourism, contributed greatly to the reduction in the mangrove areas along the northern coast of the State of Pernambuco.     

Effects of Flour Particle Size on the Textural Properties of Flour Tortillas

Three wheat flours, hard red winter (HRW), hard white winter (HWW) and soft red winter (SRW), were fractionated by sieving into four different particle size fractions, <38, 38–53, 53–75, and >75 μm. The medium fractions, 38–53 and 53–75 μm, of the HRW and HWW wheat had higher protein contents than the finest and coarsest fractions. The finest fractions had the highest levels of damaged starch. Tortillas made from the medium fractions of HRW and HWW, especially the 53–75 μm fraction, had longer rupture distance and better foldability. The finest fraction yielded tortillas with shorter rupture distance and worse foldability. Fractionation by flour particle size slightly affected protein composition of the flour. Size exclusion-high performance liquid chromatography (SE-HPLC) analyses showed that the compositions of SRW wheat proteins were significantly different from those of HRW and HWW wheat proteins. SRW had more low molecular weight (LMW) and less high molecular weight (HMW) protein than HRW and HWW had. The <38 μm fractions of HRW and HWW had more LMW proteins than other fractions. The amount of LMW proteins of flours correlated negatively with the rupture distance and foldability of tortillas. Particle size of the flours was the major factor affecting the tortilla texture.