In this article, the enzymatic aqueous extraction (EAE) of sunflower seed oil was investigated. The effects of the operational variables (temperature, water seed mass ratio, and enzyme concentration) were evaluated in order to define the conditions that maximize the free oil yield (FOY). It was observed that increasing the amounts of water and enzyme in the extraction medium was disadvantageous to the removal of the oil, and that an increase in temperature provided a higher FOY. Thus, a temperature of 60°C, seed:water ratio of 1:5 (g/g), and enzyme concentration of 1% (v/v) were defined as the conditions for maximum FOY (17.76%). The use of a buffered medium under these conditions increased the FOY to 20.34%. The composition of the oils obtained by the EAE under different experimental conditions was determined and compared with the oil obtained from Soxhlet extraction. The oils under study presented high levels of oleic and linoleic acids, which corresponded to ~90% of the composition of fatty acids. It was also noted that, depending on the extraction conditions, the oils obtained by EAE presented phytosterol and tocopherol contents similar or superior to those of the oil produced by Soxhlet extraction. Practical Applications The enzymatic aqueous extraction of sunflower oil has the potential to replace the solvent extraction method. The results reported herein show that the composition of the sunflower oil obtained by the enzymatic method was similar to that of the oil extracted by the solvent method. In addition, the enzymatic method uses mild conditions that reduce the energy required for the process and the residues are free of organic solvent.

The aim of this work was to maximize the enzymatic aqueous extraction (EAE) of sunflower seed oil using protease enzymes from the evaluation of various temperatures, pH and enzyme concentrations, using a Box-Behnken experimental design. The effect of a thermal pre-treatment of sunflower seeds on free oil yield (FOY) and oil quality was also determined. In the experimental range adopted, a lower temperature (40 °C) provided higher FOY values, as well as the intermediate pH (8.00) and maximum enzyme concentration (9% v/v). Thermal pre-treatment provided an increase in FOY in the initial extraction times (60 to 180 min) and decreased of the extraction time of 4 to 3 h to obtain the highest FOY value (~16%). The fatty acid composition of the oils obtained showed a predominance of oleic (~47.5%) and linoleic acids (~39.5%). The total phytosterol content in the samples was hardly affected by the heat pre-treatment of the seeds, while the fatty acid profile, tocopherol content and oxidative stability were not altered.

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The aim of this study was to estimate and select the drying kinetic model of thin-layer drying of banana slices and the effect of blanching pretreatment. In order, 16 semi-theoretical and/or empirical models were applied to the experimental data and compared according their coefficients of determination (R2), sum squared errors (SSE), and root mean square error (RMSE), which were predicted by non-linear regression analysis. Banana slices were subjected to the thermal blanching treatment, and then the samples were dried at 50 °C and 60°C for a period of 630 min. Chromatic characterization and shrinkage analysis were performed. Among the thin-layer drying models considered to determine the kinetic drying parameters, the semitheorical Two-term model gave the best fit for all drying conditions. Effective moisture diffusivity varied from 8.25 × 10−11 m2s-1 to 2.26 × 10−10 m2s-1 over the temperature range of the study. The increase in temperature led to a 60% average volume reduction. For color, the parameters L* and b* decreased, and a* increased in relation to the temperature increase, and blanching had a positive effect.