纳滤膜对香茅提取液中挥发性成分的影响

Effect of Nanofiltration Membrane on Volatile Components in Extraction Solution of Cymbopogon citratus

摘要:

通过分析不同孔径纳滤膜对香茅提取液中挥发性成分及含量的影响,为香茅天然香精的制备提供技术参考。使用10kDa、1kDa、500Da、300Da、200Da 5级不同孔径的纳滤膜对香茅提取液进行精细化分离,采用气质联用技术对5种不同孔径纳滤膜分离所得滤液中挥发性成分进行分析检测,计算香气活力值(odor activity value,OAV)并进行聚类分析。结果表明,香茅提取液中共检出56种挥发性成分,不同孔径纳滤膜分离得到的滤液香型基本接近,随着纳滤膜孔径的减小,滤液中烃类、酸类和酮类化合物的相对含量减少,醇类和醛类化合物的相对含量升高,化合物总含量逐渐减少。同一种挥发性成分,随着纳滤膜孔径的降低,其含量逐渐降低。通过OAV分析发现,(+)-香茅醛、香叶醇、香茅醇等18种化合物为香茅提取物特征风味的关键贡献成分。由感官相似度评价结果可知,不同孔径纳滤膜分离得到的滤液香型基本接近,不易被分辨；但纳滤膜孔径越小制得的滤液的感官辨识度越高,越容易被分辨。纳滤膜可有效地降低香茅提取液风味物质体系的复杂度,希望研究可为开发稳定实用的香茅香精产品提供技术支持和理论参考。

Abstract:

The effects of different pore sizes nanofiltration membrane on the volatile components and contents of Cymbopogon citratus extract were analyzed, which provided a technical reference for the preparation of natural flavors in Cymbopogon citratus. Five levels of nanofiltration membranes with different pore sizes of 10kDa, 1kDa, 500Da, 300Da, and 200Da were used for fine separation of Cymbopogon citratus extract, and gas chromatography-mass spectrometry (GC-MS) was used to analyze the volatile components in the filtrates separated by five kinds of nanofiltration membranes with different pore sizes. The odor activity value (OAV) was calculated and the cluster analysis was carried out. The results showed that a total of 56 volatile components were detected in Cymbopogon citratus extract, and the aroma types of the filtrates separated by different nanofiltration membranes were basically similar. With the decrease of the nanofiltration membrane pore size, the relative content of hydrocarbons, acids and ketones in filtrate decreased, while the relative content of alcohols and aldehydes increased, and the total content of compounds decreased gradually. The content of the same volatile component decreases with the decrease of the pore size of the nanofiltration membrane. By OAV analysis, 18 compounds such as (+)-citronellal, geraniol and citronellol were found to be the key contributors to the characteristic flavor of Cymbopogon citratus extract. The results of sensory similarity evaluation showed that the aroma types of the filtrates separated by different nanofiltration membranes were basically similar and difficult to be distinguished. However, the smaller the pore size of the nanofiltration membrane was, the higher the sensory identification of the filtrate was, and the easier it was to be distinguished. Nanofiltration membrane could effectively reduce the complexity of the flavor substance system of Cymbopogon citratus extract. It was hoped that the research could provide technical support and theoretical reference for the development of stable and practical Cymbopogon citratus essence products.