Abstract：
The acerola seed is an agro-industrial waste. It is a high moisture content product, rich in bioactive compounds. Drying is an alternative to make this waste available in a safe condition. The use of ethanol as a pretreatment could improve the drying process besides reducing the operation time. This study aimed to investigate the influence of ethanol pretreatment (ET) on the content of bioactive compounds, cell wall thickness, and color. The drying kinetics was studied, and the influence of external and internal resistance was discussed. The samples were immersed in ethanol for 2 min with subsequent convective drying (40 °C and 60 °C; 1 m s-1) until they reached the equilibrium condition. The ET reduced the drying time up to 36.36 %. The external and mixed control of mass transfer were identified as the governing regimes for drying this material, depending on the use of ethanol. ET led to an increase in effective diffusivity, a reduction in cell wall thickness, and preservation of the color of the dried waste. The ET positively impacted the conservation of ascorbic acid compared to untreated dried samples but was not relevant to phenolic compounds, carotenoids, and antioxidant activity. The drying process increased the bioactivity of the anthocyanins. The best condition was drying at 60 °C, pretreated with ethanol.
摘要：
针叶树种子是一种农业工业废物。它是一种高水分含量的产品，富含生物活性化合物。干燥是使这种废物在安全条件下可用的替代方法。使用乙醇作为预处理，除了减少操作时间外，还可以改善干燥过程。本研究旨在探讨乙醇预处理对生物活性化合物含量的影响,细胞壁厚度,和颜色。研究了干燥动力学，并讨论了外部阻力和内部阻力的影响。将样品浸入乙醇中2分钟，随后进行对流干燥（40°C和60°C；1ms-1），直到达到平衡条件。ET将干燥时间缩短至36.36%。传质的外部和混合控制被确定为干燥该材料的管理制度。取决于乙醇的使用。ET导致有效扩散率增加，细胞壁厚度的减少，和保存干燥废物的颜色。与未经处理的干燥样品相比，ET对抗坏血酸的保存有积极影响，但与酚类化合物无关。类胡萝卜素，和抗氧化活性。干燥过程增加了花色苷的生物活性。最佳条件是在60℃下干燥，用乙醇预处理。
