桐油出油率及主要成分随树龄和采集时间变化规律的研究

Study on the Variation of Oil Yield and the Main Components of Tung Oil with Tree Age and Harvest Time

以云南省文山油桐(Vernicia fordi)桐籽为原料,通过物理压榨法制得桐油样品,测定了油桐籽的出油率,并将所得桐油甲酯化后用气质联用分析测试,分析总结油桐籽出油率和各化学成分随树龄、采收时间的变化规律。结论表明:云南省文山州桐油不饱和脂肪酸含量在93.72%以上,桐酸含量在78.14%以上。在寒露至立冬期间内,桐籽出油率随采集时间下降,桐酸、硬脂酸随采集时间推移而下降,油酸、亚油酸、软脂酸含量随采集时间的推移而升高,且具有高显著的相关性。对于5年生及以上树龄的油桐,其出油率和桐酸含量随树龄增长而下降,油酸、亚油酸、软脂酸、硬脂酸含量均随树龄增长而增高,但无高显著相关性。桐酸含量主要受合成途径中,软脂酸到硬脂酸的转化过程和亚油酸到桐酸的转化过程的影响。研究结果可为桐油高附加值的产品开发和实际生产提供参考依据。

Tung oil samples were prepared by physical pressing method using Vernicia fordi tung seeds in Wenshan,Yunnan Province as raw materials,the oil yield of tung seeds was determined and the changes of chemical components of tung oil with the age and harvest time of tung oil were analyzed and summarized by gas chromatography-mass spectrometry(GC-MS)analysis after methylation.The results showed that:the unsaturated fatty acid content of tung oil in Wenshan prefecture of Yunnan Province was over 93.72%,and the content of tung acid was over 78.14%.During the period from cold dew to start of winter,the oil yield decreased with the harvest time,and the oil yield decreased with the harvest time,while the content of oleic acid,linoleic acid and palmitic acid basically increased with the harvest time,and had a high and significant correlation.Oil yield decreased with tree age,tung acid decreased with tree age,oleic acid,linoleic acid,palmitic acid and stearic acid increased with tree age,but there was no significant correlation.The content of tung acid was mainly affected by the conversion process from palmitic acid to stearic acid and the conversion process from linoleic acid to tung acid in the synthetic pathway.The results of this study could provide a reference for the development and actual production of tung oil high value-added product.