Abstract The effects of gamma radiation (0, 1, 2 and 3 kGy) were used to evaluate the stability and thermal degradation kinetics of anthocyanins, as well as the stability of total phenolic compounds (TPC) and antioxidant activity at different temperatures (4, 25, 35 and 45 °C) during the storage (0, 30, 60, 90 and 120 days) of black rice flour. This flour can be used as ingredient for gluten-free cereal products with higher nutritional value. For this it is necessary to preserve the anthocyanin content during thermal processing and shelf-life periods. At time 0, the dose of 3 kGy provided all of the most available bioactive compounds, raising their antioxidant potential, except for TPC. During the storage at different temperatures up to 120 days, gradual losses occurred in all the analysed parameters. Regarding the total anthocyanin content and TPC, the sample irradiated with a 1 kGy dose remained most stable. The analysis of kinetic data indicated a first-order reaction for the degradation of anthocyanins. The combination of irradiation with different temperatures may improve the shelf-life of black rice flour.

Ácidos graxos tem grande importância metabólica e estrutural. Avaliação da composição de ácidos graxos em pimentas é ainda incompleta. Polpas e sementes de seis variedades de pimentas do gênero Capsicum foram avaliadas, neste trabalho, em relação a sua composição de ácidos graxos. Foram identificados 25 ácidos graxos diferentes nas amostras, incluindo alguns com número ímpar de átomos de carbono. Os ácidos graxos mais abundantes foram palmítico (16:0), oleico (18:1n-9) e linoleico (18:2n-6). As relações poli-insaturados:saturados foram elevadas para todas as amostras, em razão das elevadas quantidades de ácidos poli-insaturados, principalmente o ácido linoleico. Nas polpas as relações de omega-6/omega-3 variaram de 1,28 a 4,33, e foram avaliadas como relativamente adequadas, tendo em vista que, na dieta humana, relações entre 0,25 e 1,0 são consideradas altamente adequadas. Nas sementes, os níveis de n-3 foram muito mais baixos do que os níveis de n-6, que foram bem elevados, resultando em baixas proporções de omega-6/omega-3, variando entre 74,2-279,6. Análise de componentes principais (ACP) explicou 93,49% da variância total dos dados. Considerando as relações poli-insaturados: saturados e omega-6/omega-3, nossos dados sugerem que entre as pimentas do gênero Capsicum avaliadas, neste trabalho, o pimentão e a pimenta habanero laranja apresentaram as melhores características nutricionais em relação à composição de ácidos graxos.

Fatty acids have a great metabolic and structural importance. Evaluation of fatty acid composition of peppers is still incomplete. Pulps and seeds from six varieties of the genus Capsicum were evaluated in this work with respect to their contents in fatty acids. A total of 25 different fatty acids, including some with odd number of carbons were identified in the samples. The most abundant fatty acids were palmitic (16:0), oleic (18:1n-9) and linoleic (18:2n-6) acids. The polyunsaturated:saturated fatty acid (PUFA/SFA) ratios for all peppers were high due to the elevated amounts of polyunsaturated acids, particularly linoleic acid. In the pulps, the omega-6/omega-3 ratios ranging from 1.28 to 4.33, were relatively adequate if one considers that ratios between 0.25 and 1.0 in the human diet are regarded as highly appropriate. In the seeds, the levels of omega-3 were very low whereas the levels of omega-6 were high, leading to very inadequate omega-6/omega-3 ratios ranging from 74.2 to 279.6. Principal component analysis (PCA) explained 93.49% of the total variance of the data. Considering the PUFA/SFA ratio and omega-6/omega-3 ratio, our data suggest that, among the peppers of the genus Capsicum evaluated in this work, the bell pepper and orange habanero pepper present the best nutritional characteristics concerning fatty acid composition.