Effects of drying temperature and genotype on morphology and technological, thermal, and pasting properties of corn starch.

The objective of this study was to evaluate the effects of drying temperature (30, 50, 70, and 90 °C) and genotype (yellow floury corn, white floury corn, and yellow flint corn) on the morphology and technological and thermal properties of corn starch. The white and yellow genotypes with floury endosperm (soft) had spherical starch granules, while the granules of the yellow flint genotype were polyhedral. White floury corn showed higher extraction yield, higher resistance during granules' swelling before the physical collapse, as it was not affected by the increase in drying temperature, and at 90 °C it presented higher breakdown and energy necessary for gelatinization. There were peak viscosity and gelatinization enthalpy reduction on starch from yellow floury corn and yellow flint corn according to the increase in drying temperature. Drying temperatures below 50 °C are indicated for all genotypes studied. White floury corn is indicated due to the higher extraction yield presented. Yellow floury corn is indicated for application in chilled and frozen products due to lower starch retrogradation. The yellow flint corn is indicated for application as a thickening agent due to higher gel hardness.

Análise de crescimento de mamona semeada em diferentes épocas / Growth of castor sown at different times

O objetivo deste trabalho foi estudar os efeitos dos fatores externos no crescimento, desenvolvimento e na produtividade da planta de mamona. O experimento foi realizado com a cultivar 'BRS Energia' semeada em três épocas nas safras 2008/09 e 2009/10 em Pelotas - RS. As variáveis avaliadas foram a taxa de crescimento relativo (TCR), taxa assimilatória líquida (TAL), produtividade e as principais variáveis meteorológicas. A maior taxa de crescimento relativo e assimilatória líquida ocorre nos períodos de temperatura média de 22,5 a 25,7°C e insolação média diária maior que seis horas, que coincidem com as semeaduras de novembro e dezembro na região de Pelotas, enquanto as maiores produtividades ocorrem nas semeaduras de outubro e novembro.

The objective was to study external effects on growth, development and plant productivity. The experiment was conducted with 'BRS Energia' sown at three times in 2008/09 and 2009/10 seasons in Pelotas, Southern Brazil. It was evaluated the relative growth rate (RGR), net assimilation rate (NAR), yield and the main meteorological variables. The highest relative growth rate and net assimilation rate occurred at an average temperature of 22.5 to 25.7°C and average daily insolation greater than six hours, which coincide with November and December sowings in Southern Brazil. The highest yields were observed in October and November sowings.