Study Of Extraction Essential Oil From Lemon Peel And Its Antioxidant And Scavenging Effect Of Nitrite

Lemon belongs to the evergreen small tree of Rutaceae,which is widely cultivated all over the world.When the lemon was processed into products,a large amount of waste such as skin and slag was produced,and the lemon peel is rich in essential oil.Essential oils are widely used in food,cosmetics and other fields due to their unique fragrance and good anti-corrosion and antibacterial properties.Exploring the extraction method of lemon peel essential oil with simple operation,high extraction rate and low cost is the key to the comprehensive utilization of deep processing in the lemon industry.Therefore,this paper used the Ulrich lemon peel of Sichuan Anyue as raw material to study the optimum process parameters of extracting lemon peel essential oil by ultrasonic assisted hydrodistillation and cellulase-assisted hydrodistillation through single factor test and response surface test.The chemical constituents of lemon peel essential oil were analyzed by chromatography-mass spectrometry;the changes of the microstructure of lemon peel were observed by scanning electron microscopy;and the antioxidant activity and the elimination of nitrite of lemon peel essential oil were compared.The main findings and conclusions were as follows:?1?The optimum extraction conditions of lemon peel essential oil by ultrasonic-assisted hydrodistillation?UAHE?were ultrasonic power 320 W,liquid-to-material ratio 15.5:1?mL/g?,ultrasonic time 36 min and distillation time 140 min.The extraction rate was 1.97%.The optimum extraction conditions of lemon peel essential oil by Cellulase-assisted hydrodistillation?CAHE?were enzymatic hydrolysis temperature 50?,enzymatic hydrolysis pH 5.0,enzymatic addition amount 1.1%,liquid-to-material ratio 16:1?mL/g?,enzymatic hydrolysis time 63 min,distillation time 140 min,and the extraction rate reached 2.12%.?2?More than twenty kinds of chemical components were identified in the lemon peel essential oil extracted by the two methods,which were similar to the chemical components of the lemon peel essential oil extracted by hydrodistillation.The main components was limonene.The ultrastruture of lemon peel was observed by scanning electron microscopy,which showed that ultrasonic wave and cellulase significantly destroyed the cell structure of the raw material and promoted the rapid release of ssential oil.?3?The lemon peel essential oil extracted by the three methods had strong antioxidant activity.However,the antioxidant activity of lemon peel essential oil extracted by the three methods was not significantly different?P>0.05?.Lemon peel essential oil had stronger antioxidant activity than limonene and?-pinene.?4?The lemon peel essential oil extracted by the three methods had obvious scavenging effects on NaNO₂.However,there was no significant difference in the scavenging effect of lemon peel essential oil extracted from the three methods on NaNO₂?P>0.05?.The lemon peel essential oil had a stronger scavenging effect on NaNO₂ than limonene and?-pinene.Compared with the hydrodistillation extraction,the above two processes had similar extraction rates,and the chemical components in the essential oils were similar,but the extraction time was significantly reduced and the efficiency improved.Therefore,ultrasonic assisted and cellulase-assisted hydrodistillation to extract lemon peel essential oil are effective methods for extracting essential oils.