Uso de películas pós-colheita para a manutenção dos atributos visuais e produção de etileno em mini-abóboras ornamentais

In recent years, consumers have shown interest in the ornamental use of some fruits that were previously used mainly for food purposes. However, the use of ‘mini-pumpkins’ for ornamentation can be limited by post-harvest aspects, such as skin depigmentation, fresh mass losses, ethylene production and respiration, which compromise the visual quality of the product, resulting in the loss of its ornamental value. The objective was to evaluate the effect of films application (control, carnauba wax, cassava starch and corn starch) in post-harvest of ornamental mini-pumpkins, aiming the shelf life prolongation (experiment 1) and reduction of ethylene production and respiration (experiment 2). The results obtained in experiment 1 pointed to lower mass loss and maintenance of the ornamental mini-pumpkins epidermis color with the application of carnauba wax film. In experiment 2, the application of carnauba wax and the ethylene action inhibitor (1-MCP) did not and respiration production of mini-pumpkins, suggesting that ethylene is not involved in the modifications that occur in the product during the time of exposure to the environment.

Analysis of endogenous process behaviour

In this paper an autonomous four-compartment model that describes the endogenous respiration in a aerobe biodegradation process is proposed and analysed theoretically. First the multi-time scale of the system's behaviour, to be taken into account in subsequent analyses, is emphasized. Then, an identifiability study, given measurements of MLVSS (mixed liquor volatile suspended solids) and respiration rate, is performed for use under practical circumstances such as in parameter estimation. It appears that the process is not fully identifiable. Hence, for the identification of some of the model parameters additional measurements or experiments, also indicated in the paper, have to be performed. Furthermore, it is shown that, under quasi-steady state conditions which in general appear shortly after initialization of an endogenous respiration experiment, the model can be reduced significantly.

STUDIES OF MARINE PLANKTONIC DIATOMS: III. SOME EFFECTS OF TEMPERATURE ON RESPIRATION OF FIVE SPECIES

The respiratory coefficient, expressed here as respiration per unit of chlorophyll, of six clones (five species) of diatoms was measured at temperatures of 5°, 10°, 15°, 20°, and 25 °C. The acclimatized cultures used were grown at each of these temperatures that supported sufficient growth. Considering any one of the five temperatures of measurement, the respiratory coefficient varied with temperature of acclimatization, but not consistently in the different clones. Moreover, for any of the given temperatures of acclimatization, there was no trend common to all clones in the relationship between respiratory coefficient and temperature at which respiration was measured. In any respiration experiment, greater differences were observed between two clones of the same species than between species differing in size by as much as two orders of magnitude. The highest respiratory coefficients were observed in the two eurythermal clones, and the increase in respiration with temperature was more regular, with Q10 = ca. 2.0. Respiration of the four stenothermal clones was more variable in relation to temperature, and both respiratory coefficients and Q10 were lower.