FLOUR FROM PINEAPPLE PEELS: INGREDIENTS WITH NUTRACEUTICAL POTENTIAL

The fruit pulp agroindustry generates a significant volume of waste, the most common destination of which is disposal, which impacts the environment and represents a waste of raw materials usable through simple processing methods. Pineapple is included among the fruits that generate large volumes of peels during processing. An alternative for the use of these residues is their conversion into flour, which can be used as ingredients to compose food supplement sources. Therefore, the objective of this work was to analyze the flours of pineapple peels of the Jupi and Pérola varieties regarding the mineral and phenolic profile, antioxidant capacity (DPPH, FRAP and ABTS), crude fiber content and hygroscopic behavior. The crushed pineapple peels were arranged in a thin layer (0.5 cm) in stainless steel trays and dehydrated in an oven with forced air circulation at a temperature of 80 °C and an air speed of 1.0 m/s until constant mass. After drying, the dehydrated peels were crushed in a knife mill to transform them into flour. The mineral profile of the flours was determined using an energy-dispersive X-ray fluorescence spectrometer and the phenolic profile using a high performance liquid chromatograph. The crude fiber content was determined by gravimetry and the hygroscopic behavior by analysis of moisture adsorption isotherms at temperatures of 20, 30 and 40 oC. The flours showed high levels of crude fiber with similarity between the varieties; the flours had nine minerals in the composition with different concentrations between the varieties, with higher levels of zinc, iron, potassium and magnesium in Jupi and phosphorus, calcium and manganese in Pérola. The antioxidant capacity of the flours was high with the three evaluation methods (DPPH, FRAP and ABTS), highlighting the highest results for the FRAP test, with emphasis on Jupi. The flours had 14 phenolic compounds, with the highest concentrations of narigenin (flavone) and chlorogenic acid (phenolic acid), with statistical similarity between the varieties. Flour water adsorption isotherms are type II and III, and all tested models (GAB, Peleg, Oswin and Halsey) can be used to estimate them. In view of the results, it was found that pineapple peel flours (Jupi and Pérola) are a source of fiber, minerals and bioactive compounds and can be used as functional ingredients in the preparation of food products.