Maria Antonia Calori-Domingues

Gamma Radiation Effects on Peanut Skin Antioxidants

Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to refined-bleached-deodorized (RBD) soybean oil. The oxidative stability of the oil samples was determined using the Oil Stability Index method and compared to a control and synthetic antioxidants (100 mg/kg BHT and 200 mg/kg TBHQ). Gamma radiation changed total phenolic content, total condensed tannins, total flavonoid content, and the antioxidant activity. All extracts, gamma irradiated or not, presented increasing induction period (h), measured by the Oil Stability Index method, when compared with the control. Antioxidant activity of the peanut skins was higher than BHT. The present study confirmed that gamma radiation did not affect the peanut skin extracts’ antioxidative properties when added to soybean oil.

Gamma radiation induced oxidation and tocopherols decrease in in-shell, peeled and blanched peanuts.

In-shell, peeled and blanched peanut samples were characterized in relation to proximate composition and fatty acid profile. No difference was found in relation to its proximate composition. The three major fatty acids were palmitic acid, oleic acid, and linoleic acid. In order to investigate irradiation and storage effects, peanut samples were submitted to doses of 0.0, 5.0, 7.5 or 10.0 kGy, stored for six months at room temperature and monitored every three months. Peanuts responded differently to irradiation, particularly with regards to tocopherol contents, primary and secondary oxidation products and oil stability index. Induction periods and tocopherol contents were negatively correlated with irradiation doses and decreased moderately during storage. α-Tocopherol was the most gamma radiation sensitive and peeled samples were the most affected. A positive correlation was found among tocopherol contents and the induction period of the oils extracted from irradiated samples. Gamma radiation and storage time increased oxidation compounds production. If gamma radiation is considered an alternative for industrial scale peanut conservation, in-shell samples are the best feedstock. For the best of our knowledge this is the first article with such results; this way it may be helpful as basis for future studies on gamma radiation of in-shell crops.

Co-occurrence and distribution of deoxynivalenol, nivalenol and zearalenone in wheat from Brazil

ABSTRACT Fusarium mycotoxins deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEN) were investigated in wheat from the 2009 and 2010 crop years. Samples (n = 745) from commercial fields were collected in four wheat producing regions (WPR) which differed in weather conditions. Analyses were performed using HPLC-DAD. Contamination with ZEN, DON and NIV occurred in 56, 86 and 50%, respectively. Also, mean concentrations were different: DON = 1046 µg kg−1, NIV < 100 µg kg−1 and ZEN = 82 µg kg−1. Co-occurrence of ZEN, DON and NIV was observed in 74% of the samples from 2009 and in 12% from 2010. Wet/cold region WPR I had the highest mycotoxin concentration. Wet/moderately hot region WPR II had the lowest mycotoxin levels. Furthermore, the mean concentration of each mycotoxin was higher in samples from 2009 as compared with those from 2010. Precipitation during flowering or harvest periods may explain these results.

Gamma Irradiation of in-Shell and Blanched Peanuts Protects against Mycotoxic Fungi and Retains Their Nutraceutical Components during Long-Term Storage

Peanut samples were irradiated (0.0, 5.2, 7.2 or 10.0 kGy), stored for a year (room temperature) and examined every three months. Mycotoxic fungi (MF) were detected in non-irradiated blanched peanuts. A dose of 5.2 kGy was found suitable to prevent MF growth in blanched samples. No MF was detected in in-shell peanuts, with or without irradiation. The colors of the control in-shell and blanched samples were, respectively, 44.72 and 60.21 (L *); 25.20 and 20.38 (Chroma); 53.05 and 86.46 (°Hue). The water activities (Aw) were 0.673 and 0.425. The corresponding fatty acids were 13.33% and 12.14% (C16:0), 44.94% and 44.92% (C18:1, ω9) and 37.10% and 37.63% (C18:2, ω6). The total phenolics (TP) were 4.62 and 2.52 mg GAE/g, with antioxidant activities (AA) of 16.97 and 10.36 μmol TEAC/g. Storage time negatively correlated with Aw (in-shell peanuts) or L *, linoleic acid, TP and AA (in-shell and blanched peanuts) but positively correlated with Aw (blanched peanuts), and with oleic acid (in-shell and blanched peanuts). Irradiation positively correlated with antioxidant activity (blanched peanuts). No correlation was found between irradiation and AA (in-shell samples) or fatty acids and TP (in-shell and blanched peanuts). Irradiation protected against MF and retained both the polyunsaturated fatty acids and polyphenols in the samples.

Laboratory evaluation of chemical control of aflatoxin production in unshelled peanuts (Arachis hypogaea L.)

Propionic acid (ammonium salt) at 3000 mg/kg (PA1) and 5000 mg/kg (PA2) of unshelled peanuts (UP); grapefruit seed extract at 5000 mg/kg (GF1) and 10,000 mg/kg (GF2); sodium orthophenylphenate at 2500 mg/kg (SOP1) and 5000 mg/kg (SOP2); thiabendazole 1000 mg/kg (TBZ1) and 5000 mg/kg (TBZ2) were studied in the laboratory, to verify their efficiency in controlling fungal growth and aflatoxin (AF) production on moist UP (16-18% moisture content). Moist UP were put into polyethylene bags with cotton plugs and incubated at 30 +/- 2 degrees C for 28 days. Treatments were considered efficient when the AF content (B1 + G1) remained under 30 micrograms/kg. PA1 treatment was efficient till 14 days of incubation and PA2 during the whole incubation period (28 days). All other treatments were not efficient, showing AF contents from 150 to 108,333 micrograms/kg during the incubation periods. Propionic acid, used as ammonium propionate, at 5000 mg/kg shows promise in controlling aflatoxin production when applied to moist unshelled peanuts.

Formas termolisada e viva de leveduras na redução de toxicidade causada por aflatoxinas

As aflatoxinas sao metabolitos hepatotoxicos produzidos por algumas linhagens de Aspergillus flavus, A. parasiticus e, eventualmente, por A. nomius sobre grande numero de produtos agricolas. Esta pesquisa foi conduzida para avaliar a capacidade de Saccharomyces cerevisiae, nas formas termolisada e desidratada viva, em reduzir os danos causados por aflatoxinas. Para tal, foi preparada uma dieta basica e desta se obtiveram quatro formulacoes: uma como controle; as demais contaminadas com aflatoxinas na concentracao de 400 mg kg-1, sendo duas com posterior adicao de 1% de leveduras, uma na forma termolisada e outra como desidratada viva. Um bioensaio com duracao de 28 dias foi efetuado com ratos Wistar. Foram realizados os estudos do peso relativo de orgaos internos e a analise do tecido hepatico dos animais. Os pesos relativos de orgaos internos de animais submetidos aos diferentes tratamentos nao diferiram estatisticamente entre si; o tecido do figado dos animais submetidos a dieta livre de aflatoxinas foi adotado como padrao de isento de toxidez; o tecido hepatico dos animais que receberam dieta controle com aflatoxinas apresentaram sinais claros de toxicidade; os animais que receberam dieta com aflatoxinas + 1% de levedura termolisada apresentaram sinais de toxicidade semelhantes ao controle com aflatoxinas; o tecido hepatico dos animais que receberam dieta com aflatoxinas + 1% de levedura viva apresentaram sinais de toxicidade menores do que os animais que receberam a dieta controle com aflatoxinas. As leveduras termolisadas nao foram capazes de suprimir os efeitos das aflatoxinas; as leveduras vivas apresentaram habilidade de reduzir os efeitos promovidos por aflatoxinas.

Distribution of aflatoxins in corn fractions visually segregated for defects

The aflatoxin distribution in corn fractions obtained after visual segregation for defects in 30 samples, known to be contaminated, was studied. Each sample was passed through a 5.0 mm round holes sieve, graded for defects and then segregated in sound kernels (regular kernels) and non-sound kernels (injured, germinated, fermented, moldy, heated, insect damaged, immature, broken, hollow, fermented up to ¼, discolored, extraneous materials, and injured by other causes), as defined by the Brazilian Official Grading rules for corn. The non-sound kernels showed the highest contamination levels in all samples. The contamination levels of non-sound kernels (20% of total weight) ranged from 23 to 1,365 µg/kg of aflatoxins (B1, B2, G1 and G2) and were higher than sound kernels (p<1%) ranging from not detected (ND) to 126 µg/kg and in 87% of these the aflatoxin contents were lower than 20 µg/kg. Statistically significant correlation indexes were found among the percentage of defective groups like fermented, heated and sprouted kernels or the total injured kernels, and the estimated contamination levels for the sound and non sound fractions. It was concluded that the non-sound kernels fraction, even being small in weight, has contributed with 84% of the estimated contamination of the samples. The segregation of the non-sound kernels would favor a reduction in the contamination of corn lots. The poorer quality corn types (types 3 and Bellow Standart) have predominated among samples of the experiment.

Aflatoxin M1 in raw milk from different regions of São Paulo state – Brazil

A total of 635 raw milk samples from 45 dairy farms, from three regions of São Paulo state – Brazil, were evaluated during 15 months for aflatoxin M1 (AFM1). AFM1 was determined by high performance liquid chromatograph with fluorescence detection. AFM1 was detected (>0.003 µg kg−1) in 72.9%, 56.3% and 27.5% of the samples from Bauru, Araçatuba and Vale do Paraíba regions, respectively. The mean AFM1 contamination considering all the samples was 0.021 µg kg−1. Furthermore, the concentration of AFM1 was quite different among Bauru (0.038 µg kg−1), Araçatuba (0.017 µg kg−1) and Vale do Paraíba (<0.01 µg kg−1) regions. Only three samples (0.5%) had higher contamination than the tolerated limit in Brazil (0.50 µg kg−1) and 64 samples (10.1%) had a higher contamination than the maximum limit as set by the European Union (0.050 µg kg−1). The estimated AFM1 daily intake was 0.358 and 0.120 ng kg−1 body weight per day for children and adults, respectively.

SELEÇÃO ELETRÔNICA PELA COR NA DESCONTAMINAÇÃO DE AMENDOIM CONTAMINADO COM AFLATOXINAS

Quarenta e dois lotes comerciais de 300 kg de amendoim descascado, produzidos em 1997 e contaminados com aflatoxinas, foram submetidos a selecao eletronica pela cor para verificar a eficiencia desse processo na melhoria da qualidade de lotes de amendoim quanto a diminuicao da contaminacao com aflatoxinas. Os lotes de amendoim foram classificados pelo tamanho como normalmente utilizados pela cerealista, sendo 22 lotes de amendoim graudo (7,5 a 7,9mm) e 20 lotes de amendoim miudo (6,4 a 7,1mm), nos quais os niveis de contaminacao inicial variaram de 7 a 3.763 mg/kg e de 76 a 3.309 mg/kg, respectivamente. Nos 42 lotes, nao foram detectadas aflatoxinas em dois lotes de amendoim graudo e 1 de amendoim miudo. Este trabalho demonstrou que o processo de selecao eletronica retirou graos altamente contaminados, concentrando-os na porcao rejeito. Apesar disso, nao houve uma melhora substancial nos niveis iniciais medios de contaminacao dos lotes indicando que a distribuicao das aflatoxinas estava generalizada, uma vez que, os graos selecionados tambem estavam contaminados. Em lotes com menor contaminacao pode funcionar. Novos estudos serao realizados.

Ozonation of whole wheat flour and wet milling effluent: Degradation of deoxynivalenol (DON) and rheological properties

ABSTRACT The objective of this study was to evaluate the reduction on the levels of the mycotoxin deoxynivalenol (DON) in whole wheat flour (WWF) with different moisture levels, on the wet milling effluent through ozone (O3) processing, as well as the impact of ozonation on the rheological properties of flour. The results have shown that the reduction of DON was improved with increasing moisture and exposure time of WWF and wet milling effluent to ozone. The maximum reduction was about 80%, proving that ozonation is an effective and promising technology in reducing mycotoxins in different products. However, the process altered the rheological profile of WWF. Therefore, further studies are needed to better understand the process.