Tavares Lucas Silveira, Junqueira Luciana Affonso, de Oliveira Guimarães Ívina Catarina, de Resende Jaime Vilela
Laboratory of Food Refrigeration, Department of Food Science, Federal University of Lavras, P.O. Box 3037, Lavras, Minas Gerais 37200000 Brazil.
J Food Sci Technol. 2018 Feb;55(2):457-466. doi: 10.1007/s13197-017-2954-4. Epub 2017 Nov 20.
Chia seeds ( L.) when immersed in water, produce a highly viscous solution due to the release of mucilage, high molecular weight complex carbohydrates with wide application in the food industry. Thus, this study involve development of method for extracting mucilage from chia seed based on mechanical process and low temperature. The method involve extraction by cold pressing and drying by freeze-drying, which was compared to the traditional hot extraction method. The chia seed mucilage cultivated in Brazil was extracted successfully using the previously mentioned extraction method. Rheological analysis including thixotropy, flow curve and frequency sweep of mucilage was done. Microstructure was examined by scanning electron microscopy. The optimal process at 27 °C gave yield of 8.46%. The rheograms showed that the apparent viscosity decreased with increase in shear rate and this effect was most notable in the dispersions obtained by cold extraction and with high concentrations. The gum obtained using CE presented higher values for thixotropic behavior. The storage modulus (G') was consistently higher than the loss modulus (G″) and the data indicated formation of 'weak gel' structure of the dispersions. SEM indicated macroscopic fibrous structure of mucilage obtained through cold extraction process, indicating that the macromolecular network formed by fibrous material contained in mucilage maintained its structure in the process of deep freezing and freeze-drying.
芡欧鼠尾草种子（芡欧鼠尾草）浸泡在水中时，由于黏液质的释放会产生一种高粘性溶液，黏液质是一种高分子量复合碳水化合物，在食品工业中有广泛应用。因此，本研究涉及基于机械工艺和低温从芡欧鼠尾草种子中提取黏液质方法的开发。该方法包括冷压提取和冷冻干燥，将其与传统的热提取方法进行了比较。使用上述提取方法成功提取了巴西种植的芡欧鼠尾草种子黏液质。对黏液质进行了流变学分析，包括触变性、流动曲线和频率扫描。通过扫描电子显微镜检查微观结构。在27℃的最佳工艺下产率为8.46%。流变图表明，表观粘度随剪切速率的增加而降低，这种效应在冷提取得到的分散体和高浓度分散体中最为显著。使用冷提取法获得的胶表现出更高的触变性值。储能模量（G'）始终高于损耗模量（G''），数据表明分散体形成了“弱凝胶”结构。扫描电子显微镜显示通过冷提取过程获得的黏液质具有宏观纤维结构，表明黏液质中含有的纤维材料形成的大分子网络在深度冷冻和冷冻干燥过程中保持了其结构。
