青贮对广西柠檬草挥发性成分和营养成分的影响研究

Research on the Effects of Guangxi Lemongrass Silage on the Volatile Components and Nutrients

采集广西生长的柠檬草,以传统水蒸气蒸馏提取柠檬草精油,分析柠檬草的绝干得油率、挥发油的柠檬醛(橙花醛和香叶醛)以及月桂烯含量。采用顶空固相微萃取‒气相色谱质谱联用技术,对柠檬草青贮前后挥发性成分进行分析,研究柠檬草的粗脂肪、粗蛋白、中性洗涤纤维、酸性洗涤纤维、粗纤维等营养指标在青贮前后的变化。结果表明,采集的柠檬草样本主要是柠檬香茅和曲序香茅,柠檬香茅和曲序香茅的粗脂肪、中性洗涤纤维、粗纤维含量经青贮后降低,而酸性洗涤纤维含量增加,其他营养成分变化不大。采用顶空固相微萃取‒气相色谱质谱联用技术鉴定出曲序香茅中有40种挥发性成分,青贮后,橙花醛含量从19.80%降至12.76%,香叶醛含量从30.73%降至17.37%,橙花醇从2.51%升高至12.23%,香叶醇从9.83%升至15.77%。青贮发酵菌提升了挥发性成分中橙花醇和香叶醇的相对含量,柠檬草可作为反刍饲料的原料。本研究为进一步探索饲养反刍动物提供科学依据。

To study the oil yield of lemongrass and the contents of citral(nerol aldehyde and geranyl aldehyde)and laurene in the essential oils of lemongrass from Guangxi,the essential oils of lemongrass were extracted via steam distillation and analyzed via gas chromatography(GC).The volatile organic compounds of lemongrass before and after silage were analyzed by headspace solid-phase microextraction gas chromatography-mass spectrometry(HS-SPME-GC-MS),and the contents of crude fat,crude protein,neutral detergent fiber,acid detergent fiber,and crude fiber were studied.The lemongrass samples collected were mainly Cymbopogon flexuosus and C.citratus,and the contents of crude fat,neutral detergent fiber,and crude fiber in both types of lemongrass decreased after silage.However,the contents of acid detergent fibers increased,and the contents of other nutrients slightly differed.HS-SPME-GC-MS was used to identify 40 volatile constituents in currant lemongrass.After lemongrass silage,the nerol aldehyde and geranyl contents decreased from 19.80%to 12.76%and from 30.73%to 17.37%,respectively,whereas the nerolol and geranyl contents increased from 2.51%to 12.23%,and from 9.83%to 15.77%,respectively.It was concluded that fermentation bacteria increased the content of alcohols in volatile organic compounds and converted aldehydes into alcohols.Therefore,lemongrass can be used as the raw material for ruminant feed,and this research provides a scientific basis for further exploration of the feeding of ruminants.