Evaluation of two fruit ecotypes (totai and sclerocarpa) of macaúba (Acrocomia aculeata)

• Macaúba is a promising material for the production of oil for biodiesel.
• The potential of macaúba for oil production depends of ecotypes and the environment.
• Germination of macaúba is influenced by the removal of the operculum and temperature.

Macaúba (Acrocomia aculeata) fruit has great potential for oil production, surpassed only by the African oil palm (Elaeis guineensis). Studies of the use of macaúba oil for biodiesel are on-going, and the co-products of oil processing are excellent nutritional sources when used in food and feed. Several ecotypes of macaúba occur, but their oil production potential remains to be verified. Thus, in this study, fruits of two ecotypes of macaúba were evaluated to determine their mineral and proximate compositions, biometric characteristics, the physicochemical composition of the nut oil, and their germination characteristics. Mineral analyses consisted of the evaluation of N, P, K, Ca, Mg, Cu, Zn, and Mn. Proximate analyses included measurements of moisture, dry matter, crude protein, crude fibre, lipids, mineral matter, ash, and carbohydrates. Biometric characterisation included the masses of the endocarp, nut, mesocarp, epicarp and fruit, the longitudinal diameter of the fruit and nut, the endocarp thickness, and the fruit volume. Progibb® (0, 50, 100, and 200 mg L−1) was used at temperatures of 25 °C and 35 °C to evaluate germination. The acidity, iodine content, saponification properties, and humidity of the nut oil were analysed. For the mineral, proximate, biometric and nut oil analyses, the means of the sclerocarpa ecotype were higher than those of the totai ecotype. In the biometric evaluations, the percentages of each part of the fruit of the totai ecotype were higher than those of the sclerocarpa ecotype, although the averages were lower in relation to fruit. The seed lot used in this study did not produce good germination, but the use of Progibb® was effective at 35 °C for the totai ecotype; both evaluated ecotypes exhibited high levels of contaminated and ungerminated seeds.