Influência da temperatura do ar de secagem e da utilização do ácido etilenodiaminotetracético na qualidade do óleo e caracterização do fruto de macaúba

Abstract

This study was conducted to determine and evaluate the physical properties of the macaúba fruits, model the phenomenon of shrinkage using three temperatures, compare and evaluate the chemical properties of the oil extracted from the macaúba pulp fruit, in the presence of different EDTA concentrations, during the storage and evaluate the combined effect of temperature and storage on the oil quality. It used macaúba ripe fruit collected directly from the ground, from trees native to the region of Piranga - MG. It determined the fruits physical properties, such as: specific dimensions, circularity, sphericity, geometric diameter, projected area, surface area, bulk density, true density, porosity and shrinkage. Evaluations were made, in the quality of crude oil extracted from macaúba pulp fruit, such as: acid value, iodine value, peroxide value, saponification value, moisture, volatile material, analysis spectroscopy at ultraviolet and density on the storage period. Based on these results, it concluded: a) the dimensions and the geometric mean diameter of the macaúba fruits decreased by reducing the moisture; b) the macaúba fruit shape didn’t influenced by the moisture reduction, circularity and sphericity didn’t change with the reduction moisture; c) the moisture reduction affects the physical properties of the macaúba fruits, the bulk density and the true density were reduced and the porosity increased; d) the projected area and surface area of the macaúba fruit decreased with the moisture reduction; e) the linear model represented satisfactorily the phenomenon of macaúba fruit shrinkage for all temperatures studied; f) reducing the moisture results in decreased of 8.81, 9.36 and 10.26 %, in the fruit volume, for the 60, 70 and 80 °C respectively, these values are considered small to compared with the others agricultural products, therefore may be neglected in modeling process; g) increasing the temperature and consequently the drying rate, it had a direct effect on the shrinkage kinetics; h) the acid value, saponification value and concentration of dienes and triene were increased with storage time. The iodine value, concentration of carotenoids and density were decreased. The peroxide value of drying control treatment was increased and then was decreased, however, for others treatments the peroxide values only increased during the storage; i) the oil content, moisture and material volatile didn’t change during storage; j) exponential equations can be used to describe the behavior of acid value, iodine values and saponification values during the 100 days. However, for the peroxide value of drying control treatment the best fit to a polynomial equation; k) in the treatment with added 1.0 % EDTA to the oil was recommended to protect it against the oxidation processes, during the storage. The oils from the drying control and the EDTA addition control treatments, were showed the worst values of the indices examined, were the less efficient to keep the oil quality; l) among the drying treatments, which used the 60 °C, to reduce the moisture of macaúba fruit, was showed the best results in the oil conservation during the 100 days, though the treatments that used EDTA, were more efficient to keep oil quality.