Study On The Formation Pattern Of Sesamol And Anti-Inflammatory Activity During The Processing Of Sesame Oil

As a high-quality edible vegetable oil,sesame oil has strong antioxidant activity,which is mainly attributed to the presence of various antioxidant and bioactive substances in sesame oil,including sesamolin and sesamin.During the processing of sesame oil,sesamolin is degraded to sesamol,which contains phenolic hydroxyl groups.Sesamol not only has stronger antioxidant properties than sesamolin,but also has anti-mutagenic,anti-inflammatory,anti-aging and chemopreventive properties.Therefore,the targeted regulation of the conversion of sesamolin to sesamol through suitable process conditions of oil production provides a certain theoretical basis and technical support for the development of high-quality sesame oil products rich in sesamol,which is of great significance to enhance the product quality and nutritional value of sesame oil.In this study,three processing methods,microwave,sprouting and acid-catalyzed,were used to investigate the formation pattern of sesamol in sesame oil during processing,optimize the processing conditions,and evaluate the effects of the above processing methods on the biological activity of sesamol in sesame oil through in vitro anti-inflammatory activity assay.The main research contents and conclusions are as follows:Firstly,the changes of sesamol content in sesame oil under different microwave conditions were studied,and the quality indexes,nutrients,harmful substances and sensory quality of sesame oil produced under different microwave conditions were investigated.The most suitable microwave conditions for sesamol-riched oil were determined:sesamol content in sesame oil is proportional to microwave time,and the appropriate moisture content can promote the production of sesamol.The sesamol content was higher at 5 minute microwave time with 9%moisture content,6 minute with 7%moisture content and 7 minute with 5%moisture content.When the microwave time was 5 minutes,the characteristic flavor of sesame oil was weak,and when the microwave time was 6 minutes,the production of harmful substances increased,and the burnt taste was heavy.The moisture content will reduce the oxidative stability of sesame oil,and the above factors determine the most suitable microwave process conditions for microwave time of 6 minute and sesame seed moisture content of 7%.Secondly,the effects of germination time,temperature and sesame seed spreading density on sesamol production were investigated.With the increase of the above factors,the sesamol production showed a trend of increasing and then decreasing,and reached the maximum at germination time of 24 hours,germination temperature of 28°C and spreading density of 0.2g/cm~2.Pretreatment of sesame seeds by soaking in water for 12 hours could increase the sesamol content by 56.3%;pretreatment by ultrasonication for 30 minutes could increase the sesamol content from 0.32 mg/100g to 0.39 mg/100g,an increase of 18.0%;pretreatment by soaking in phytic acid for 24 hours could significantly increase the sesamol content of sprouted sesame oil,and the sesamol production at a phytic acid concentration of 8%was highest.The maximum value was 0.87 mg/100g,which increased the sesamol content by 171.9%compared to the control cold-pressed sesame oil.The in vitro antioxidant capacity of sesame oil was significantly enhanced by the sprouting process as determined by the antioxidant activity.Thirdly,the effects of acid treatment on sesamol formation in sesame oil were investigated by single-factor and response surface optimization tests,and the effects of oil refining process on sesamol content in acid-treated sesame oil and the antioxidant activity of acid-treated sesame oil were studied.The results showed that the regression model of the results of the response surface method to optimize the acid-catalyzed process was good,and the misfit term was not significant.The three acid-catalyzed process factors influenced the sesamol production in the following order:reaction time>catalyst addition>reaction temperature.The optimum acid-catalyzed process conditions for sesamol-riched sesame oil were:reaction temperature 69.11°C,catalyst addition 4.38%,reaction time 52.31 minutes,and maximum sesamol production 134.80 mg/100g.The sesamol content increased during the decolorization process and decreased significantly during the deodorization process,and the sesamol content decreased from 134.80 mg/100g to 50.22 mg/100g after the whole refining process.Compared with the control cold-pressed sesame oil,the in vitro antioxidant capacity of the optimal process acid-catalyzed sesame oil was enhanced.Fourthly,the effect of the above processing method on the anti-inflammatory activity of sesame oil was evaluated by establishing an in vitro inflammation model of LPS-induced mononuclear macrophages in mice.First of all,by examining the amount of NO production by different concentrations of LPS on RAW264.7 cells,1μg/m L of LPS was selected as the modeling concentration.The sesame oil concentrations with no toxic effect on cells were screened by CCK-8 method,and three dose groups were determined as low,medium and high with sesame oil concentrations of 0.05 mg/m L,0.1 mg/m L and 0.5 mg/m L.The levels of pro-inflammatory factors NO and TNF-αproduced by RAW264.7 cells induced by four sesame oil samples were determined using ELISA,and it was found that sesamol content enhanced the anti-inflammatory activity of sesame oil produced by the three processing methods.