Secagem do bagaço de azeitona (Olea europaea L.) para obtenção e caracterização de farinha

Abstract

The olive tree (Olea europaea L.) is a plant belonging to the Oleaceae family. Due to its xerophytic structure, it has a good development in regions that have a hot and dry climate. Olive pomace is the main by-product obtained from the extraction of olive oil, whose residues generated in the industrial process of olives require better management, and the best strategy for this is to reduce them and use these in products that generate a greater added value to this co-product. Thus, its use as agricultural compost material, in industrial energy production and its use in animal and human feed emerge as alternatives, in the latter case, the material must be dry. Drying is a unitary operation aimed primarily at reducing water activity, thus inhibiting the growth of microorganisms and reducing enzymatic activity, which increases the shelf life of the dry product. In this context, this course conclusion work aimed to evaluate the drying of olive pomace in a dryer with perpendicular air flow to obtain pulp flour. Through the 2² factorial experimental design technique with rejoinder at the central point, the effects of the temperature (50, 60 and 70°C) parameters were studied and drying air speed (1.0, 1.5 and 2.0 m/s) in the characteristics of dried olive pomace. The influence of these parameters was investigated by the quantification of bioactive compounds and dried product moisture. The flour obtained from the dried pulp in the best drying condition was characterized in relation to proximate composition, bioactive compounds, total carotenoids (CT), water activity (aw), water solubility index (ISA), water absorption index (IAA), particle size (granulometry) and real specific mass. In the characterization of fresh bagasse, values of moisture, ash, proteins, lipids, fibers and carbohydrates of 65.07±0.73% (wb) were found; 3.75±0.0%; 4.19±1.02%; 19.94±0.04%; 22.25±3.75% and 45.33±3.70%, respectively. Regarding bioactive compounds, 45.33±3.70 mg gallic acid/100 g for CFT, 73.70±0.53% for AA and 29.97±1.30 µg/g for C.T. The flour from the pulp of the olive pomace was prepared in the drying condition which provided a lower loss of bioactive compounds and shorter drying time, at a temperature of 70°C and drying air speed of 1 m/s. The values of moisture, ash, proteins, lipids, fibers and carbohydrates for the flour obtained were 8.48±0.05% (bu), 3.45±0.12%, 6.75±0.80%, 26.72±0.68%, 40.18±2.45% and 14.42±4.10%, respectively. As for the physical characteristics, values were found for water activity, solubility index, absorption index, particle size and real density of 0.601±0.60, 34.65±0.75%, 0.87±0.02 g/g, 97.96±1.68 µm and 1.266±0.001 g/cm3 , respectively. The results found suggest the potential of the olive pomace pulp flour in the formulation of food products, emphasizing its fiber content and bioactive compounds.