集合超声波、超滤、弱碱性等电点沉淀技术, 开发了一种从废弃烟叶中提取可溶性蛋白的新工艺, 并构建了一套物理、化学、生物参数评价体系. 经优化后的工艺路线如下: 在0.085 mol/L 磷酸缓冲液 (pH=7.85) 条件下, 以 1∶8 料液比进行超声波提取, 经分级离心、过滤/超滤, 并通过 0.11 mol/L [H+] 溶液调节等电点 pH=5.5, 成功提取了分子量约为 55 kDa及大于 200 kDa 的混合蛋白, 其氨基酸组成分析能满足成人必需氨基酸需求. 红外光谱分析未见明显果胶、多糖特征. 采用温和弱碱-等电点提取技术结合物理提取方法, 有效解决了传统提取方法存在的问题, 展现了良好的通用性, 为废弃烟叶的资源化利用及工业化生产提供了新的思路.

This study innovatively combined ultrasonic extraction, ultrafiltration, and weakly alkaline isoelectric precipitation technologies to devise a process for the efficient ex-traction of soluble proteins from discarded tobacco leaves. Additionally, a comprehensive evaluation system incorporating physical, chemical, and biological parameters was established. By optimizing the process, an effective protocol was identified as follows. A pH 7.85 phosphate buffer at a concentration of 0.085 mol/L was utilized for ultrasonic ex-traction with a material-to-liquid ratio of 1∶8. Subsequently, fractionated centrifugation and filtration/ultrafiltration were performed, followed by adjustment of the solution to an isoelectric point pH of 5.5 using a 0.11 mol/L [H+] solution. This protocol facilitated the successful extraction of mixed proteins with molecular weights of approximately 55 kDa and exceeding 200 kDa. The amino-acid composition of the extracted proteins satisfied the essential amino-acid requirements of adults. Infrared-spectrum analysis indicated the absence of significant pectin or polysaccharide features. This research introduced a gentle,weakly alkaline isoelectric point extraction approach, combined with physical-extraction techniques. This method not only overcomes the limitations of conventional extraction processes but also exhibits broad applicability. Innovative pathways are presented herein for the resourceful utilization and industrial-scale production of discarded tobacco leaves.