Secagem por liofilização e convecção do fruto da pupunha (Bactris gasipaes Kunth).

Abstract

Peach palm is a species from the tropical region of the Americas, native from the Amazon, a species that holds oil reserves, palm hearts and bunches with many small oily and fibrous fruits. Pupunha has a high potential for diversity and nutrients and it is a promising product for the consumer and agroindustrial market. This work was carried out with the objective of studying the drying process by freeze drying and forced convection of the in natura fruit of the pupunha (Bactris gasipaes Kunth). The raw and cooked fruits were processed to obtain powder by lyophilization in order to evaluate the technique for the preservation of the nutritional constituents in the pupunha. Afterwards, convective drying was carried out at temperatures of 50, 60 and 70°C and drying air velocity (0,72, 0,87 and 1,028m/s), respectively, in order to obtain a bar of cereal from the best condition of this process. The pupunha in natura, lyophilized powder and raisins were evaluated for their physicochemical composition and bioactive compounds. For the formulation of the cereal bar it was used a complete experimental design 22 + three central points, with independent variables (raisins of pupunha and concentrate whey protein) and as dependent variables (instrumental evaluation - strength and firmness and nutritional evaluation - protein and total energy value). The formulations were evaluated for their nutritional composition. The results showed that the pupunha samples were considered non-toxic, making it possible to use them for food processing. The crude and cooked lyophilized samples obtained values of minimum water activity and considerable values of lipids 20,42 and 21,551 g (100 g)-1, respectively, and proteins 7,57 and 7,28 g (100 g) -1. As for the convective drying, the diffusion approximation model, Page e Silva et alli obtained good adjustment to the experimental data, of the temperature studied. The intermediate temperature (60 º C) obtained the best quality results, obtaining an increase in the amount of pigments, being this the best condition to be used as an ingredient in the elaboration of cereal bars. Cereal bar formulations referring to the central point (F5, F6 and F7), with low caloric content, maximization of protein content and acceptability of texture parameters and collaboration with chewing achieved better results.