Secagem de caju (Anacardium occidentale) pelo método foam-mat com otimização prévia da espuma

Abstract

The cashew tree (Anacardium occidentale) is original from the northeast of Brazil, it is found mainly in the states of Ceará and Rio Grande do Norte. Its fruit and “false fruit”, the cashew nut and the cashew, respectively, besides presenting an important economic value for the region, they also represent a significant nutritional value to the healthy for those ones who consume it. As it is rich in potassium, phosphorus, magnesium, calcium and other minerals, besides its high concentration of vitamin C, it helps to prevent flu, to heal hurts , to contract the muscles when there is need and to relieve the pain. The cashew also acts as an anti-inflammatory, helps the treatment of bronchitis, arthritis, intestinal colic, jaundice and even helps to treat people with diabetes. Despite of the benefits the cashew gives to the human organism, the cashew nut is still more worthy and it represents the biggest demand of the consumer market. Because of it, there is a need of making better use of the cashew through alternative methods, as the drying process, which avoids that the higher consume of the cashew nut brings waste of the cashew. The drying process extends the shelf life of a food, increases its added value and minimizes the costs with transportation and storage. The aim of this study is analyse the drying process of cashew through the foam-mat method, from an 23 experimental design to optimize the foam with three independent variables: albumin concentration (3 and 7%), Liga Neutra® concentration (0,50 and 1,00%) and whipping time (5 and 25 minutes), with three repetitions at the central point. The best condition for the formulated foam, which presented 520% of maximum expansion, was the foam with 7% of albumin, 0,50% of Liga Neutra® and 25 minutes of whipping time. The foam was submitted to the drying process for different temperatures (60, 70 and 80 ºC). The drying curves showed a period of steady rate followed by a period of decreasing rate. To the drying data were adjusted Fick and Page models and it presents a correlated index higher than 0,99. As it was expected, the results showed that both the effective diffusivity and the specific rate of drying, K, grew as the drying temperature grew. The drying rates from the steady period were between 1,0964 and 1,817 g/min. After the drying process the obtained products were analysed through the Tukey test. The moisture, the activity of water, the pH, the total soluble solids and the solubility decreased with the increase of the temperature. The hygroscopicity of the powders was between 24,43 and 41,66%, but it did not diverge statistically.