Açaí has a high content of anthocyanins and unsaturated fatty acids, and drying parameters can affect the stability of these compounds. This study used a conductive thin-film dryer at a laboratory scale to mimic the (vacuum) drum drying of açaí pulp. The effect of drying chamber pressure on the drying kinetics and powdered product characteristics was investigated. Hot air drying and freeze-drying experiments were performed as references. A pilot-scale conductive dryer, namely a vacuum drum dryer, was used as well to dry açaí pulp. Conductive drying at low pressures led to lower boiling temperatures and shorter drying times but also more vigorous bubble formation. The anthocyanin content and antioxidant activity of contact-dried samples at low pressures were comparable to those of freeze-dried and significantly higher than those of hot air-dried. However, conductive drying caused greater lipid oxidation compared to freeze-drying and hot air drying. Oil loss was observed during vacuum drum drying except for the lowest pressure and the shortest drying time. Therefore, the results suggest that chamber pressure during conductive thin film drying should be carefully selected to obtain high-quality açaí powder.

巴西莓含有高含量的花青素和不饱和脂肪酸，干燥参数会影响这些化合物的稳定性。本研究使用实验室规模的导电薄膜干燥器来模拟巴西莓纸浆的（真空）滚筒干燥。研究了干燥室压力对干燥动力学和粉末产品特性的影响。进行了热风干燥和冷冻干燥实验作为参考。还使用了中试规模的传导干燥器，即真空滚筒干燥器来干燥巴西莓浆。低压下的传导干燥导致更低的沸腾温度和更短的干燥时间，但也更剧烈的气泡形成。低压接触干燥样品的花青素含量和抗氧化活性与冻干样品相当，显着高于热风干燥样品。然而，与冷冻干燥和热风干燥相比，传导干燥引起更大的脂质氧化。除压力最低和干燥时间最短外，在真空转鼓干燥过程中观察到油量损失。因此，结果表明，应仔细选择导电薄膜干燥过程中的腔室压力，以获得高质量的巴西莓粉。