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.

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.

ABSTRACT

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.

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 microM) solution. In hypercholesterolemic-diet rats, relaxation in intact MABs was significantly decreased with ac-n-BuOH-EF bolus (300, 600, 900 microg) 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 microg 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 microg bolus of Aq-EF. The guanilate cyclase inhibitor methylene blue (100 microM) 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.