Eliana Badiale Furlong

Antioxidant activity and enzyme inhibition of phenolic acids from fermented rice bran with fungus Rizhopus oryzae

The solid-state fermentation (SSF) has been employed as a form making available a higher content of functional compounds from agroindustrial wastes. In this work, the effect of SSF with the Rhizopus oryzae fungus on the phenolic acid content of rice bran was studied. Phenolic extracts derived from rice bran and fermented rice bran were evaluated for their ability to reduce free radical 1,1-diphenyl-2-picrihidrazil (DPPH) and for the ability to inhibit the enzymes peroxidase and polyphenol oxidase. The phenolic compound content increased by more than two times with fermentation. A change in the content of phenolic acids was observed, with ferulic acid presenting the greatest increase with the fermentation, starting from 33μg/g in rice bran and reaching 765μg/g in the fermented bran. [corrected]. The phenolic extracts showed an inhibition potential for DPPH and for the peroxidase enzyme, however did not inhibit the polyphenol oxidase enzyme.

Vascular Responses to Extractable Fractions of Ilex paraguariensis in Rats Fed Standard and High-Cholesterol Diets

The authors investigated the vasorelaxant properties of the aqueous (Aq-EF) and acid n-butanolic (acn-BuOH) extractable fractions from Ilex paraguariensis leaves. Perfusion pressure was evaluated using isolated and perfused mesenteric arterial beds (MABs) from rats fed hypercholesterolemic and standard diets. Extract-induced vasorelaxation in the presence and absence of various inhibitors was examined following precontraction of the MABs with methoxamine (30 μM) solution. In hypercholesterolemic-diet rats, relaxation in intact MABs was significantly decreased with ac-n-BuOH-EF bolus (300, 600, 900 μg) in comparison to those in standard-diet rats. After the endothelium was stripped from the MABs, the vascular responses to ac-n-BuOH-EF and 900 μg bolus of Aq-EF were significantly changed. Treatment of the MABs with an inhibitor of nitric oxide synthase, N G -nitro-L-arginine methylester hydrochloride (L-NAME, 10 mM), did not change either ac-n-BuOH-EF- or Aq-EF-induced vasodilation except for the 900 g bolus of Aq-EF. The guanilate cyclase inhibitor methylene blue (100 μM) did not affect vasodilation for either fraction in the MABs from the hypercholesterolemic-diet rats. The chronic oral administration of I. paraguariensis extract in hypercholesterolemic-diet rats resulted in a significant reduction in serum levels of cholesterol and triglycerides. These results suggest that I. paraguariensis ac-n-BuOH-EF and Aq-EF induce vasodilation in standard-diet rats in a dose-dependent manner and that the hypercholesterolemic diet substantially reduced the effect of ac-n-BuOH-EF on precontracted MABs.

Evaluation of a modified QuEChERS extraction of multiple classes of pesticides from a rice paddy soil by LC-APCI-MS/MS.

A new method for the determination of clomazone, fipronil, tebuconazole, propiconazole, and azoxystrobin in samples of rice paddy soil is presented. The extraction of the pesticides from soil samples was performed by using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. Some extraction conditions such as salt addition, sample acidification, use of buffer, and cleanup step were evaluated. The optimized method dealt with a single extraction of the compounds under study with acidified acetonitrile, followed by the addition of MgSO(4) and NaCl prior to the final determination by liquid chromatography-atmospheric chemical pressure ionization-tandem mass spectrometry. Validation studies were carried out in soil samples. Recoveries of the spiked samples ranged between 70.3 and 120% with relative standard deviation lower than 18.2%. The limits of quantification were between 10 and 50 μg kg(-1). The method was applied to the analysis of real samples of soils where rice is cultivated.

Effect of particle size and ammonium sulfate concentration on rice bran fermentation with the fungus Rhizopus oryzae

The effects of rice bran particle size (0.18-0.39mm) and ammonium sulfate concentration in the nutrient solution (2-8g/L) on biomass production, protein and phenolic content generated by solid state fermentation with the fungus Rhizopus oryzae (CCT 1217) were studied. Particle size had a positive effect on biomass production and a negative effect (p⩽0.05) on protein and phenolic contents. Ammonium sulfate concentration had a positive effect (p⩽0.05) on biomass and phenolic content gain. Cultivation of fungus in rice bran with particle size of 0.18mm and in the presence of 8g/L ammonium sulfate, resulted in protein levels of 20g/100g dry wt and phenolics content of 4mg/g dry wt. These values were 53 and 65% higher than those achieved with unfermented rice bran. The results demonstrate that the fermentation process increased the value of compounds recovered for potential use in food formulations.

Antioxidant properties of Spirulina (Arthospira) platensis cultivated under different temperatures and nitrogen regimes

The main aim of this work was to investigate the effects of temperature and nitrogen concentration on the antioxidant potential of extracts from Spirulina (Arthospira) platensis biomass. S. platensis biomass obtained at 35oC and with 1.875 g.L-1 or 2.5 g.L-1 of sodium nitrate in the culture medium presented higher concentrations of phenolic compounds. The antioxidant potential of methanol extracts of biomass on the enzymatic browning caused by peroxidase were 29 and 35%, respectively, being the reduction related to the amount of phenolic compounds present in this extract.

Polycyclic aromatic hydrocarbons in rice grain dried by different processes: evaluation of a quick, easy, cheap, effective, rugged and safe extraction method.

This study aims at developing a method for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) in rice grain samples by combining the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method and determination by gas chromatography-mass spectrometry (GC-EI-MS). Quantification limits ranging from 1 to 5μgkg(-1) were obtained. Recoveries ranged from 70% to 106% for most of the 16 PAHs under analysis. The optimised methodology was applied to assess safety concerning the content of PAHs in white and parboiled rice samples, dried by gas and wood burning. Although benzo(a)pyrene, the marker used for evaluating the carcinogenic risk of PAHs in food, was not detected in the samples, naphthalene and phenanthrene were detected in all of them. Since cereals have been shown to be an important source of PAHs in the diet, methods that perform the evaluation of the quality of this food group become relevant.

Avaliação da atividade antifúngica de extratos fenólicos de cebola, farelo de arroz e microalga Chlorella phyrenoidosa

The objective of this work was to relate the levels of total phenolic in onion, rice bran, and Chlorellaphyrenoidosa with the antifungal activity tested against the fungus Rhyzopus oryzae. The phenolic compounds of onion were extracted in three solvent systems: aqueous, methanolic, and with ethila acetate, whereas the phenolic compounds of rice bran and Chlorella phyrenoidosa were extracted with methanol. The extracts were quantified with the Folin-Ciocalteau reagent. The method to evaluate the antifungal activity employed was the diluted Agar technique. The Rhyzopus oryzae had its development inhibited in the presence of onion methanolic and aceto-ethylic extracts and rice bran methanolic extracts at the following phenolic concentrations, 86; 2.6, and 46 µgphenolic.mL-1agar, respectively. The aqueous extracts from onion and the methanolic extract from Chlorellaphyrenoidosa did not inhibit fungal growth under the phenolic concentrations tested.

Phenolic compounds and antioxidant activity in fermented rice (Oryza sativa) bran.

In this study, it was evaluated the influence of different shapes, sizes, and maturation stages on the yield of albedo flour and pectin content of yellow passion fruit rinds. Random samples of 40 fruits were used, and the data were compared using significance intervals at 5%. Weight, skin color, fruit size and shape, pulp yield, mesocarp thickness, amount of epicarp and mesocarp, moisture content, and pectin yield were determined. The maturation stages were defined according to measurements of the yellow color of the skin. The shape and size patterns were defined according to the length/width ratio (equatorial diameter) of fruits. It was found that the epicarp thickness was not correlated to fruit shape and size, but it was thicker in ripe fruits. The mesocarp was thiner in small ripe fruits, but it did not change with fruit shape. Pulp yield was higher in ripe fruits, and it was not influenced by shape and size of fruits. It was concluded that the content of albedo flour can account for 3.9% of the weight of processed fruits, whereas the amount of pectin powder can account for up to 0.9% of the fruit weight.

Otimização e validação de método empregando quechers modificado e lc-esi-ms/ms para determinação de agrotóxicos em cebola

An evaluation of the pesticides extraction from onion using a modern sample preparation method (QuEChERS) and determination by liquid chromatography tandem mass spectrometry was carried out. All the calibration curves showed r>0.99. The recoveries ranged between 61.8 and 120.0% with relative standard deviation lower than 20% for all compounds. Due to the occurrence of matrix effect, the quantification was performed using matrix-matched calibration. The limits of quantification of the method were between 0.0005 and 0.05 mg kg-1. The method shows the advantages of not require the clean-up step and consume low volume of organic solvents, decreasing time, costs and residues.

Phenolic compound in beans as protection against mycotoxins.

Phenolic compounds, their inhibitory activity against fungal amylase and the occurrence of aflatoxins were determined in edible beans. The free, conjugated and bounded phenolic compounds and their phenolic acid profiles were determined in ten bean varieties. A method for aflatoxin B1, B2, G1 and G2 determination and confirmation by LC-MS/MS was validated. The red and carioca beans presented the highest total phenolic content (1.8 and 1.2mg.g(-1), respectively); the fradinho and white beans the lowest (0.18 and 0.19mg.g(-1), respectively). In the free and conjugated forms, chlorogenic acid was present in 60% of the samples, while in the bounded phenolic, ferulic acid was in 90% of the samples. The phenolic extracts were able to inhibit fungal amylase, and the PCA analysis confirmed that the relation between the chlorogenic and gallic acids is important to this effect. The absence of aflatoxins in samples confirm the protector effects of these phenolic compounds.