The Effects Of Different Drying Methods On The Color,volatile Matter And Antioxidant Activity Of Zanthoxylum Bungeanum Leaves

Pepper leaves are the by-product of Zanthoxylum bungeanum,with unique hemp flavor and rich nutrition.Researches showed that pepper leaves were rich in aromatic oil,fiber,glycoside,flavonoids and other components.Pepper leaf has huge yield,but pepper farmers always were concerned with fruit harvest and ignored the rational utilization of pepper leaf.For pepper leaf,selecting the appropriate drying methods and conditions could not only accelerate the drying speed,improve the production efficiency,but also largely reduce the destruction of the nutrients.Therefore,this paper studied the effects of different drying methods on the color,volatile substances and antioxidant properties of the leaves of DaHongPao pepper leaves,in order to open up a new consumer market and new economic growth point for the comprehensive utilization of the leaves.The specific research results were as follows:1.Through research,it was found that the four drying methods of natural drying,hot air drying,vacuum drying,medium and short wave infrared drying had different effects on the color difference and chlorophyll content of the Dahongpao pepper leaves.The influences from small to large were: infrared drying,vacuum drying,natural drying,hot air drying.Compared with fresh pepper leaves,the loss of chlorophyll caused by drying was obvious,but compared with other drying methods,the loss caused by infrared drying was relatively low.2.Through the detection of electronic nose,it was found that the substances with higher content in pepper leaves were sulfur-containing substances,aromaticsubstances,sulfur-containing and chlorine-based substances,and a small amount of nitrogen-oxygen substances.Vacuum drying and infrared drying had better retention of volatile substances in pepper leaves.GC-MS was used to analyze the components of several dried pepper leaves.It was found that thirty five kinds of substances were detected by vacuum drying and infrared drying,thirty one kinds of substances were detected in dried pepper leaves and thirty kinds of substances were detected in hot air dried pepper leaves.3.The content of polyphenols,flavonoids and tannins and antioxidant capacity of pepper leaves were significantly affected by different drying methods.After infrared drying and vacuum drying,the content of polyphenols,flavonoids and tannins in pepper leaves was relatively high,showing good DPPH,ABTS free radical scavenging ability and iron reducing ability.4.Through linear regression analysis,it was found by fitting that the infrared drying process of pepper leaves conformed to Page model,and the model P value was less than 0.05,indicating the fitting was significant.The model could be used to describe the infrared drying process of pepper leaves.