Drying of butiá pulp by the foam-layer method and characterization of the obtained powder

Abstract The objective of this work was to develop a drying process using the foam-layer method to obtain the powder from butiá (Butia spp.) pulp, as well as to characterize this powder according to its yield and physicochemical and technological characteristics. The foam was optimized for density and stability by varying whipping times and albumin and xanthan gum concentrations. Foam drying was optimized for vitamin C retention and yield using different foam thicknesses and drying temperatures. The optimized foam showed a density of 0.25 g cm-3 and a high stability, being suitable for subsequent drying. The lowest foam thickness (0.50 cm) and the highest drying temperature (80°C) resulted in the highest retention of vitamin C, whereas the increase in drying temperature improved yield. The butiá pulp powder obtained under the optimized condition presented an acid pH of 3.25, a low humidity of 7.97%, a water activity of 0.206, a water retention capacity of 4.90 g H2O per gram of powder, a solubility of 74.40%, a soluble solids content of 61°Brix, and a predominantly yellow color. The foam-layer drying method can be used to obtain butiá pulp powder.摘要 本研究旨在开发一种泡沫层法干燥工艺，以从布蒂亚（Butia spp.）果肉中制备粉末，并从得率、理化特性与工艺特性维度对该粉末进行表征。通过调控搅打时长、白蛋白与黄原胶的添加浓度，优化泡沫的密度与稳定性；通过设置不同的泡沫厚度与干燥温度，以维生素C保留率及产品得率为优化指标，对泡沫干燥工艺开展优化。优化后的泡沫密度为0.25 g·cm⁻³，稳定性优异，可满足后续干燥工序要求。实验结果显示，最低泡沫厚度（0.50 cm）与最高干燥温度（80℃）可实现最高的维生素C保留率，而提升干燥温度可提高产品得率。在优化工艺条件下制备的布蒂亚果肉粉末，其pH值为3.25（呈酸性），含水率低至7.97%，水分活度为0.206，持水能力为每克粉末吸附4.90 g水，溶解度达74.40%，可溶性固形物含量为61°Brix，色泽以黄色为主。泡沫层干燥法可用于制备布蒂亚果肉粉末。