Obtenção da farinha de batata-doce (Ipomoea Batatas) pelo processo Foam Mat

Abstract

The sweet potato (Ipomoea potatoes) is one of the most produced and consumed foods worldwide, being of easy cultivation and high nutritional value. Easily adapted, this tuber is rich in carbohydrates, thus possessing a high energy value. In addition to carbohydrates, it is a food rich in minerals (such as iron, calcium), vitamin A and B vitamins, being a good food for the immune system. The low shelf life and the low exploitation of agroindustrial potential are factors that influence the search for adding value to this product. Sweet potato flour maintains the nutritional value and can be used to enrich foods such as breads, biscuits, mass in general. The best known method for the production of flour is the drying of sweet potatoes in natura followed by grinding, however the study of simpler and economical dehydration methods are sought. Foam drying is a relatively simpler and more cost-effective method of increasing the contact surface between the mixture and the hot air, and it has advantages of being made in a shorter time and at a lower temperature when compared to Other drying methods. The present study consisted in analyzing the foam-mat drying in an experimental design 3² + 2, with the addition of Emustab® (1%, 2% and 3%) and temperature (70°C, 80°C and 90°C) as independent variables. Production yields were greater than 90% and as reconstituted flours retained as physical-chemical properties of the material prior to treatment. Moisture, water activity and hygroscopicity indicate good storage conditions. The increase in the addition of the blowing agent and the temperature had effects on the drying rates and on the effective diffusion coefficients, obtaining the fit of the Fick model to the experimental data of the drying no descending rate period. The Page model presented a good fit to the experimental data of the moisture ratio as a function of time, for all conditions studied. Key-words: Sweet potato, Ipomoea potatoes, drying, foam layer, flour.