Otimização da extração do óleo de baru (Dipteryx alata Vog.) e influência das condições de armazenamento das amêndoas e safras na qualidade dos óleos obtidos

Abstract

Among the products extracted from the Cerrado is the baru (Dipteryx alata Vog.), From which one obtains an almond, rich in proteins, fibers and lipids. Recent studies demonstrate the benefits obtained by the consumption of baru and oil for health, due to the antioxidant action, preventing cardiovascular diseases and neoplasias, antirheumatic action, control of hypercholesterolemia and hormonal regulator. Due to this, the objective is to optimize the extraction of the baru oil by mechanical pressing, to obtain a higher efficiency of extraction and oil with quality and photo oxidative stability. The optimization was carried out through Central Compound Rotation Delineation (CCRD), determining the best rotation and temperature parameters for oil extraction. The responses were efficiency, water content, acidity, peroxide value, specific extinction (at 232 nm and 270 nm), refractive value, iodine value and saponification value. It was also evaluated the quality and photostability of baru oil extracted from almonds stored under different conditions (in the fruit and outside the fruit) for the two harvests, 2015 and 2016. The mathematical model obtained for extraction efficiency was highly significant (p- value = 0.0045). The oils obtained in all the tests presented good oxidative quality with results for acidity from 0.17% to 0.26%, peroxides from 0.93 to 4.02 meq.O2.kg-1

, specific extinction at 232 nm of 1.876 to 2.218, 270 nm from 0.39 to 0.45, refractive value of 1.4636 to 1.4642, saponification

value of 183.08 and 191.22 mg KOH.g-1 and iodine number of 82.28 to 88.83 g I2 .100g- 1

. Significant differences (p <0.05) were observed by the Duncan test in the quality of the oils of the harvests of 2015 and 2016 due to the storage conditions as well as the photostability of the oils. It was observed antioxidant activity values higher than those already reported in the literature for baru oil, from 14.44 ± 1.06 to 31.27 ± 1.45% DPPH. A strong and positive correlation of the moisture content of the oil with the peroxide value (r2 = 0.818), specific extinction at 232 nm (r2 = 0.761) was observed. Through the PCA, the iodine content and the antioxidant capacity are the main variables that correlate with the storage conditions of the almonds. By means of these results, the handling of the almonds for preservation of the quality and increase the shelf life should be stored in the fruit, with humidity below 6%, extraction parameters with rotation below 36.5 rpm and cake almond outlet temperature above 100 oC, being fundamental the packaging in bottle amber to avoid photo-oxidation reactions.