Effects of two methods of drying on quality physical and chemical grain winter corn - RS, stored for 6 months/ <br>Efeitos de dois métodos de secagem sobre a qualidade físico-quìmica de grãos de milho safrinha - rs, armazenados por 6 meses

The objective of this study was to evaluate the physical and chemical quality of maize, harvested in July, in Eldorado do Sul, Rio Grande do Sul, using two drying methods and stored for 6 months in bulk. The study was conducted in the EEA of UFRGS, in Eldorado do Sul - RS in the crop year 2007/2008, the harvested grain with humidity of about 30%, and were subsequently subjected to drying in-bin drying of concrete, using two methods, 1. Stationary drying with natural air is not heated at room temperature, 2. Stationary drying with natural air heated with LPG. The height of layer for drying was one meter in all silos. After drying the grains were stored in bulk in their own silos, where they were drying out. Subsequently, at intervals of 3 months were carried out following physical chemical analysis: 1000 grain weight, volumetric weight, moisture, crude protein, ether extract, ash and carbohydrates. The drying of the grains was conducted with air flow of 2.52 m3.s-1, the average air temperature during drying with natural air was 17 °C, during drying with air natural heated with LPG was 22 °C. The average air drying naturally was 48 hours, while for drying with warm air naturally with LPG was 34 hours. Grains of corn were harvested with moisture content of 31.88% and then dried with natural air to reach 15.70% moisture and air heated with natural LPG up 13.39% moisture. Based on the results we can conclude that: 1. The drying with natural air heated with LPG was faster than air drying in natural conditions of the study; 2. In conditions of high humidity and low temperature drying with natural air should be performed with care due to the equilibrium moisture content; 3. The two drying methods are feasible in terms of quality, but the losses of crude protein, lipid and carbohydrates were higher during the first six months of storage in dry grains with natural air; 4. The natural air drying can be an excellent alternative and low cost to small farmers to dry grain.<p><p>O objetivo deste trabalho foi avaliar a qualidade físico-química de milho safrinha, colhidos no mês de julho, no município de Eldorado do Sul, Rio Grande do Sul, submetidos a dois métodos de secagem e armazenados por 6 meses a granel. O trabalho foi realizado na EEA da UFRGS em Eldorado do Sul - RS na safra agrícola 2007/2008, os grãos colhidos com umidade de aproximadamente 30%, e posteriormente foram submetidos à secagem em silo secador de concreto armado, através de dois métodos, sendo: 1. Secagem em leito fixo com ar natural não aquecido, na condição ambiente; 2. Secagem em leito fixo com ar natural aquecido com GLP. A altura de camada para a secagem foi de um metro em todos os silos. Após a secagem os grãos foram armazenados a granel nos próprios silos, onde foram realizadas as secagens. Posteriormente e em intervalos de 3 meses foram realizadas as seguintes análises físicas químicas: peso de 1000 grãos, peso volumétrico, umidade, proteína bruta, extrato etéreo, cinzas e carboidratos. A secagem dos grãos foi realizada com fluxo de ar de 2,52 m3.s-1, a temperatura média do ar durante a secagem com ar natural foi de 17 °C e durante a secagem com ar natural aquecido com GLP foi de 22 °C. O tempo médio de secagem com ar natural foi de 48 horas, enquanto que para a secagem com ar natural aquecido com GLP foi de 34 horas. Os grãos de milho foram colhidos com umidade de 31,88% e posteriormente secos com ar natural até atingirem umidade de 15,70% e com ar natural aquecido com GLP até umidade de 13,39%.