Secagem solar e convencional de grãos de abóbora.

Abstract

Concentration area in processing and storage of agricultural products. In order to reduce waste losses and waste, non-food conventional foods have been incorporated into food as an alternative source of nutrients, This is why leaves, bark and grains, among them pumpkin squash, are incorporated into food preparations such as "multimixtures". In this work we studied the drying of pumpkin seeds in solar dryer and greenhouse. Whole grains, grains without pumpkin seed meal and flour. Oven drying with air circulation was performed at temperatures of 40, 50, 60, 70 and 80 ° C. For solar drying Two dryers were used, one for drying during the day and one for drying night time. The daytime solar dryer consists of a square box made of internally zinc coated with black painted i A piano glass plate. The nighttime dryer (ACSN) is composed of two independent water circulation systems with registers to control circulation of water between the solar collectors and the thermal reservoir and from this to the chamber drying During the day the circuit formed by the solar collectors and the reservoir, with water circulation increased by a power pump photovoltaic. At night this circuit was interrupted and the integrated circuit by the thermal reservoir and the drying chamber, whose circulation of the water was provided by the thermal siphon principle. The solar dryer for night use was mounted so that the water heated during the day, stored in a reservoir circulated in a heat exchanger overnight to provide heat for the drying chamber. The adaptation of a pump connected to a photovoltaic panel to the daytime water heating circuit increased dryer drying efficiency ACSN, ​​which reached a maximum temperature of 65 ° C. The drying in solar dryer and in sun exposure associated with the ACSN dryer drying at 40 ° C and between 40 and 50 ° C in a greenhouse, respectively. The use of the dryer nighttime resulted in faster drying, overcoming the water loss of the control. The diffusional, exponential two-term models, Henderson & Pabis, logarithmic and Page were adjusted to the data of kiln drying day and night solar dryers, where all models used were satisfactory, especially diffusional and logarithmic.