7 research outputs found
Rice and rice bran from different cultivars: physicochemical, spectroscopic, and thermal analysis characterization.
Várias cultivares de arroz tem sido desenvolvida no intuito de obter grãos com características de cultivo e composição apropriadas, que são responsáveis pela indicação de uso/consumo dos grãos. Assim, justifica-se a necessidade de caracterização das diferentes cultivares de arroz. No presente estudo, o arroz branco e o farelo de arroz das cultivares BRS AG, BRS Pampa, e BRS 358, cedidas pela EMBRAPA, foram caracterizadas a partir de análises físico-químicas, espectroscopia no infravermelho (FTIR-ATR) e análises térmicas. Nas amostras de arroz branco, o conteúdo de umidade, lipídios e cinzas não diferiu entre as cultivares. A BRS Pampa teve o maior teor de proteínas e o menor teor de carboidratos. A BRS Pampa e BRS 358 tiveram maior teor de ácido fítico. O maior conteúdo de carboidratos observado no arroz branco da cultivar BRS AG confirma sua indicação de uso na produção de bioetanol. Nas amostras de farelo de arroz, a BRS teve maior teor de lipídios, proteínas e ácido fítico, e o menor de carboidratos totais. A análise por FTIR-ATR e análise térmica permitiram correlacionar as propriedades físico-químicas do farelo de arroz e arroz branco com a composição química dentro de cada cultivar estudada. O arroz branco e o farelo de arroz exibiram degradação térmica a 300 °C. O conteúdo de lipídios, proteínas, cinzas e ácido fítico foram superiores no farelo em comparação ao arroz branco para todas as cultivares, o que demonstra a importância do uso desse subproduto.Título em português: Arroz e farelo de arroz de diferentes cultivares: caracterização físico-química, por espectroscopia e análise térmica
Effect of microwave and oven roasting methods on total phenol, antioxidant activity, phenolic compounds, and fatty acid compositions of coffee beans
Isolation of two lactobacilli, producers of two new bacteriocin-like substances (BLS) for potential food-preservative use
Potential biomonitoring of atmospheric carbon dioxide in Coffea arabica leaves using near-infrared spectroscopy and partial least squares discriminant analysis
Antimicrobial peptides produced by bacteria: The bacteriocins
Bacteriocins are the subset of antimicrobial peptides (AMPs) produced
by bacteria. They are small amphipathic peptides that interact with bacterial
membranes leading to cell death. Most of the best known are produced by lactic
acid bacteria used as food fermentation starters, because of their potential use as
food preservatives. Bacteriocins are divided into two groups: lantibiotics that present posttranslational condensation rings and unmodified peptides. The first are
subdivided into elongated versus globular lantibiotics, while four subgroups are
recognized among unmodified bacteriocins. The genetic organization is in clusters
that may reside into plasmids or transposons, formed by the structural gene, the
export and immunity determinants, the quorum sensing governing production and
any modification genes. Bacteriocins are active at extremely low concentrations
(nM range) due to a dual mode of action: (a) binding to the membrane phospholipids and (b) specific recognition of surface components, both of which collaborate
in pore formation. Development of resistance to bacteriocins is very infrequent due
to the presence of two targets and is usually due to unspecific modifications of the
cell envelope. Bacteriocins are used as food preservatives, either after total or partial
purification or as extracts of producing bacteria. In situ production is also used, with
the advantage of producing early lysis of the starter bacteria and ripening acceleration of the fermented product. They may also form part of hurdle technologies
and be incorporated into packaging systems to allow extended liberation. Medical
and veterinary applications are in their infancy but good results have been obtained
against infection by Gram-positive bacteria and Helicobacter pylori.Peer reviewe