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This study investigated the effects of variations in oil contents and fatty-acid composition, density, viscosity, acid values, saponification values, specific oxidative stability, and antioxidant concentration of Acrocomia totai kernel oil during fruit maturation. Fatty acids were quantified using 1 H nuclear magnetic resonance (NMR) spectroscopy, gas chromatograph-flame-ionization detector (GC-FID), and Fourier transform Raman (FT-Raman) spectroscopy analyses. The results showed that all physicochemical characteristics and oil composition changed during the ripening stage. The CG-FID analysis showed a reduction in the unsaturated fatty-acid content (from 78.8% to 22.1%), with a proportional increase in the saturated fatty-acid contents (from 21.6% to 77.9%). The difference in the fatty-acid composition was confirmed by analysis of the 1 H NMR and FT-Raman spectra. The degree of unsaturation was calculated to determine the oxidative stability of oil. These results suggest that the fruit's maturation contributes to the specific oxidative stability. The antioxidant concentration revealed higher contents of carotenoids in the ripe fruit (0.16 mg of carotenoid per 100 g KERNEL ) when compared to the unripe fruit (0.05 mg of carotenoid per 100 g KERNEL ). In the total phenolics analysis, there was no change in concentration over ripening time. These results show that kernel oil has physicochemical properties comparable with high-quality commercial vegetable oils, suggesting that it is a promising alternative to conventional vegetable oils.

BACKGROUND Biodiesel produced from renewable energy sources has gained significant attention in the arena of fuel diversification from fossil sources. However, the conventional treatment to separate biodiesel from glycerol produces large volumes of wastewater, causing environmental concerns. The present study aims to assess ceramic membrane technology for improving biodiesel separation and purification, and overcome the traditional process constraints. RESULTS Biodiesel was obtained by ethylic transesterification of crude, degummed and refined soybean oil. The tangential ultrafiltration (α‐Al2O3/TiO2) performance in separating and purifying the produced biodiesel was evaluated based on the glycerol retention capacity and on the permeate flux values. The separation was improved by use of acidified water [0.5% and 1% (m/m)] which promoted the demulsification of the reaction final mixture. In the proposed system, the glycerol was retained, and the biodiesel was the continuous phase. Higher free fatty acid content in the crude and degummed soybean oil, not only favoured the glycerol transfer over the aqueous phase, which was retained by the membrane, but also resulted in the lowest flux decline rates. An increase in the oil acidity reduced the consumption of acidified water. As the pore diameter (0.05 μm and 20 kDa) and the transmembrane pressure (1 and 2 bar) decreased, the glycerol retention increased allowing the system to fulfill commercialization requirements. CONCLUSION The results of this study showed that the novel ultrafiltration process is efficient in separating biodiesel from glycerol and reducing wastewater generation when compared with the conventional process. © 2020 Society of Chemical Industry