Experimental Study On The Deterpene Process Of Ginger Essential Oi

Vegetable essential oils are widely used in many fields such as cosmetics,food and health care,and medicine due to their unique composition,biological activity,and special aroma.The main chemical composition of plant essential oil is terpene compounds,which are unstable in nature and prone to oxidation and polymerization reactions,resulting in deterioration of the quality of the essential oil.Compared to other components of the essential oil,terpene compounds have little contribution to aroma,and terpene compounds are difficult to dissolve in water.These factors limit the application range of plant essential oil,so it is necessary to conduct de terpene treatment for plant essential oil,That is,while separating as much as possible the terpene compounds that contribute little to aroma in ginger essential oil,keeping as much as possible the oxygenated compounds that contribute much to aroma,thereby improving the quality of plant essential oil and increasing the added value of essential oil products.This study is a systematic experimental study on the process of removing terpenes from ginger essential oil obtained from Guizhou small yellow ginger by supercritical CO₂extraction using solvent method and adsorbent supercritical CO₂ extraction method,respectively.The relevant research contents and conclusions are as follows:（1）Direct injection and headspace solid phase microextraction（HS-SPME）were used to qualitatively and quantitatively analyze the volatile components of ginger essential oil by GC-MS,and the effects of the two injection methods on the composition and content of ginger essential oil were analyzed;HS-SPME-GC-MS technology was used to qualitatively and quantitatively analyze the volatile components of ginger essential oil,and combined with odor activity value（OAV）to analyze the contribution of volatile components to aroma.HS-SPME method is an analytical method for the preparation of water-soluble ginger essential oil by solvent extraction of terpene from ginger essential oil,and OAV analysis is used to confirm the separation and retention of the target substance;The direct injection method uses the analytical technique of adsorbent supercritical CO₂ extraction for ginger essential oil to confirm the separation and retention of the target substance.（2）Based on the determination of the target diterpenoids and target retention compounds for the solvent method of removing terpenes from ginger essential oil,the relative content of these two components was used as the evaluation index.Using ethanol and propylene glycol as extractants,a single factor experiment was conducted to obtain the optimal technical parameters for the preparation of water-soluble ginger essential oil by solvent method for the removal of terpene.The optimal technical parameters for the preparation of water-soluble ginger essential oil by ethanol solvent method for the removal of terpene were as follows:ethanol aqueous solution with a concentration of 50%,centrifugation speed of 5000 r/min,centrifugation time of 15min,stirring temperature of 20℃,stirring time of 30 min,and solid-liquid ratio of 3:20（g:m L）.Under the conditions of this technical process parameter,the relative content of the target triterpenoid was reduced from 49.06%to 28.18%,and the target retained aroma was increased from 19.08%to 29.89%.The optimal technical parameters for the preparation of water-soluble ginger essential oil by propylene glycol solvent method are:propylene glycol aqueous solution with a concentration of 70%,centrifugation speed of 6000 r/min,centrifugation time of 15 min,stirring temperature of 30℃,stirring time of 60 min,and solid-liquid ratio of 3:20（g:m L）.Under the conditions of this technical process parameter,the relative content of the target triterpenoid was reduced from 49.06%to 36.75%,and the target retained aroma was increased from19.08%to 25.70%.（3）Based on the determination of the target diterpenoids and target residues for the removal of terpenes by the ginger essential oil adsorbent supercritical CO₂extraction method,the relative content of the two components was taken as the evaluation index.Based on a single factor experiment and orthogonal experimental optimization,the optimal experimental combination of target triterpenes and target retention was obtained.Taking the minimum relative content of target triterpenes in ginger essential oil as a consideration,the optimal process parameters for ginger essential oil triterpenes removal were determined:the liquid-solid ratio of ginger essential oil to silica gel was 10:6（g:g）,the extraction pressure was 20 MPa,the extraction temperature was 55℃,the CO₂ flow rate was 600 m L/min,and the extraction time was 50 min.Under the conditions of this technical process parameter,the relative content of the target triterpenoid was reduced from 67.39%to 1.44%,and the relative content of the target retention was increased from 15.99%to 72.91%.This method has a significant effect on the removal of terpenoids from ginger essential oil,and the adsorbent silica gel can be reused at least four times.