Estudo da secagem infravermelho de sementes de melancia (Citrullus lanatus)

Abstract

The watermelon Citrullus lanatus species is a globally known and consumed fruit, that has the flesh rich in provitamin A, vitamins C, B complex and some minerals. The seeds of this fruit, usually discarded, also bring benefits to human beings, whether in nutrition, by your high level of fats, proteins and minerals like magnesium, calcium, potassium, iron, phosphorus and zinc, or even in the pharmaceutical industry through the oil extracted to assist in the treatment of cancer, cardiovascular problems, and hypotensive action home remedies for the treatment of Burns, swelling and arthritis. Among the components of the watermelon seeds include amino acids such as arginine and citrulline, which are important functions for the human body. Soon, the study of this material become increasingly common due to their applications, so that the drying technologies appear as an important method of processing this material, especially the use of infrared radiation or combined with other techniques such as convection and flashing that offer several advantages to the final product, since they provide good energy efficiency, high quality of the final product and reduced processing time. Given this, the work aimed to evaluate the quality, energy efficiency and continuous infrared drying kinetics, hybrid (infrared radiation associated with convection) and flashing under the conditions: 45, 65 and 85° C for the temperature of the infrared source (IR), 0,4; 0,8 and 1,2 m/s for the forced convection and burst of 1:1 proportions; 1:5 and 1:9. The samples were performed with dryings, approximately 11,5 g of seeds, and were commanded by internal diffusion of moisture of the material, allowing the use of the theoretical model of Fick to describe the period the descending rate and the use of semi empirical equations of Lewis, Brooker and Page to represent the whole process. Effective moisture diffusivity (Deff), on the various drying conditions, ranged from 0,617 to 0,625 x 10-10 m ²/s and the comparison between the results of dryings showed increased Deff with increased supply temperature IR and reduced consumption 46,79% energy by combining the highest temperature of the parsed source with longer samples burst. Colorimetric analysis of seed indicated higher levels of variation of color when applied alone IR radiation. However, this variation was softened with the Association of radiation IR with the forced convection at room temperature and flashing periods. Thus, the drying process via IR radiation is promising, being its best condition, among those analyzed, the drying via continuous IR radiation with source temperature at 85°C.