Melissa dos Santos Oliveira

Changes in lipid, fatty acids and phospholipids composition of whole rice bran after solid-state fungal fermentation

The aim of this study was to evaluate fermented rice bran phospholipids, lipids and fatty acid content in a fermentation solid system with Rhizopus oryzae fungus. For this, aliquots were withdrawn every 24h over 120 h. The content of phospholipids was determined by colorimetric method. Esterified fatty acids were separated by gas chromatography, then identified and quantified. The total lipids from fermented rice bran (FB) decreased from 20.4% to 11.2% in the range between 0 h and 120 h of fermentation while phospholipid contents were increased up to 2.4 mg P g(lipid)(-1). In fermented bran, oleic, palmitic and linoleic acids prevailed, with a decrease in saturated fatty acids (20%) and increase in the unsaturated ones (5%). This study showed that rice bran fermentation with R. oryzae can be applied to the production of phospholipids altering the saturated to unsaturated fatty acid ratio.

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.

Aflatoxins: Contamination, Analysis and Control

Aflatoxins are toxic metabolites produced by different species of toxigenic fungi, called mycotoxins. Humans can be exposed to aflatoxins by the periodic consumption of contaminated food, contributing to an increase in nutritional deficiencies, immunosuppresion and hepatocellular carcinoma (Wagacha & Muthomi, 2008). Aflatoxins (AFs) have a wide occurrence in different kind of matrices, such as spices, cereals, oils, fruits, vegetables, milk, meat, etc. Among the 18 different types of aflatoxins identified, the major members are aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2), M1 (AFM1) and M2 (AFM2) which are produced by Aspergillus flavus and/or Aspergillus parasiticus. Strains of A. flavus can vary from non-toxic to highly toxigenic and are more likely to produce AFB1 than AFG1. Strains of A. parasiticus generally have less variation in toxigenicity and produce AFB1 and varying amounts of AFB2, AFG1 and AFG2 (Coppock & Christian, 2007). Other fungi have been described in the literature as aflatoxins’ producers such as A. bombycis, A. ochraceoroseus and A. pseudotamari (Klich et al, 2000; Mishra & Das, 2003). A. flavus and A. fumigatus have also been identified as pathogens for animals and humans (Zain, 2011). The order of acute and chronic toxicity is AFB1 > AFG1 > AFB2 > AFG2, reflecting the role played by epoxidation of the 8,9-double bond and also the greater potency associated with the cyclopentenone ring of the B series, when compared with the six-membered lactone ring of the G series. AFM1 and AFM2 are hydroxylated forms of AFB1 and AFB2 (Mclean & Dutton, 1995; Wogan, 1966). In the primary fungi metabolism a lot of interrelated reactions catalyzed by enzymes occur, with the objective of promoting energy and primary metabolites (synthetic intermediates and macromolecules), ensuring the growth and reproduction of fungi. Secondary

Application of protein-phenolic based coating on tomatoes (Lycopersicum esculentum)

The aim of this study was to investigate the use of protein-phenolic based coating made from fermented rice bran on cherry tomatoes (Lycopersicum esculentum). Tests were performed with glycerol 3% (v/v), glycerol with protein-phenolic rice bran extract (5%), glycerol with protein-phenolic extract after 96 hours of fermentation (5%), and a control (without coating). The coated cherry tomatoes were kept at room temperature for 28 days. Mass loss, pH and acidity, total soluble solids, and carotenoids were determined every 96 hours. The coating made from the biomass extract reduced the carotenoid and acidity levels in the fruits studied by 17 and 21.1%, respectively, compared to the control. The coating proved an efficient barrier to water vapor with mass loss of 57% less than the control suggesting that it can be used as an alternative for vegetable tissue conservation.