Seasonal changes of fructans in dimorphic roots of Ichthyothere terminalis (Spreng.) Blake (Asteraceae) growing in Cerrado.

Cerrado is a floristically rich savanna in Brazil, whose vegetation consists of a physiognomic mosaic, influenced by rainfall seasonality. In the dry season rainfall is substantially lower and reduces soil water supply, mainly for herbs and subshrubs. Climatic seasonal variations may well define phenological shifts and induce fluctuations of plant reserve pools. Some Cerrado native species have thickened underground organs that bear buds and store reserves, as adaptive features to enable plant survival following environmental stresses. Asteraceae species accumulate fructans in storage organs, which are not only reserve, but also protecting compounds against the effects of cold and drought. Ichthyothere terminalis is one Asteraceae species abundant in cerrado rupestre, with underground organs consisting of thickened orthogravitropic and diagravitropic roots. The objectives of this study were to analyze how abiotic environmental factors and plant phenology influence fructan dynamics in field grown plants, and verify if fructan metabolism differs in both root types for one year. I. terminalis accumulates inulin-type fructans in 10-40% of the dry mass in both root types. Fructan dynamics have similar patterns described for other Asteraceae species, exhibiting a proportional increase of polysaccharides with the senescence of the aerial organs. Multivariate analyzes showed that, as rainfall decreased, environmental factors had a stronger influence on metabolite levels than phenological shifts in both root types. Only slight differences were found in fructan dynamics between orthogravitropic and diagravitropic roots, suggesting they may have similar fructan metabolism regulation. However, these small differences may reflect distinct microclimatic conditions in both root types and also represent the influence of sink strength.

Dinâmica microbiana em contrafilés bovinos embalados a vácuo: sistemas de terminação e tempo de estocagem / Microbial dynamics in the vacuum-packaged meat cuts: production system and storage period

A qualidade da carne embalada a vácuo é de grande importância para o comércio. Neste contexto, no presente estudo foi avaliada a dinâmica microbiana de cortes cárneos bovinos Longissimus dorsi, denominado comercialmente por contra filé, embalados a vácuo e armazenados a 0 ± 1 °C no estabelecimento de abate durante cinco períodos de estocagem. Foram analisadas amostras de cortes cárneos provenientes de bovinos anelorados, fêmeas, terminados em dois sistemas de produção, sendo 15 adultos criados a pasto, com média de 45 meses de vida e 15 bovinos jovens de 12 meses de idade em confinamento de alto desempenho. Procedeu-se a avaliação bacteriológica das carnes nos períodos de tempo correspondentes à zero, 30, 45, 60 e 75 dias após o abate e embalagem. A avaliação microbiológica foi efetuada pela contagem de aeróbios viáveis, bactérias ácido lácticas, Enterobacteriaceae, psicrotróficos, anaeróbios, determinaçãodo Número Mais Provável (NMP) de coliformes totais, coliformes termotolerantes e Escherichia coli, análise de pH e temperaturas dos cortes. O sistema de terminação influenciou parcialmente na dinâmica microbiana. As carnes embaladas a vácuo podem apresentar micro-organismos deteriorantes e patogênicos, provenientes de contaminação ambiental ou fecal. Quanto maior o período de estocagem dos cortes cárneos, a contagem de micro-organismos avaliados foi maior.