Study Of The Main Composition Of Zanthoxylum Leaf And Its Dry Characteristics

The resource of pepper leaves is rich in China, but they were not sufficiently comprehens ive. A lot of pepper leaves were discarded or burned. To avoid wasting pepper leaves, we sho uld open up new consumer markets and create new economic growth point.The effects of the picking period and variety of pepper leaves on the main components were investigated. In add ition, the Fengxian dahongpao pepper leaf was chosen to study the effects of three different dr ying methods(hot air drying, vacuum drying, short-wave infrared drying) on the flavonoids a nd total phenolic contents of dried pepper leaves by determining the optimal parameters of the three drying method.The main conclusions of this study are as follows:(1) The picking period and variety of pepper leaves showed significant impacts on the main ingredient compositions. From flowering to fruiting period, protein, flavonoid and sugar were all reduced in seven varieties of pepper leaf, while the ash was increased.The total phenol content of most species was increased. However, total phenol content of Fugu pepper leaves and No Thorns Hancheng were reduced. The fat content in 6 species of pepper leaves was increased except Wild pepper leaf. The physical and chemical indicators of different species in the same picking period showed significant differences.The amount of protein in Dahongpao was the highest, while the wild pepper leaves had the most total phenolic, flavonoids and reducing sugar. On the other hand, the least of total phenolic and flavonoids contents and the highest fat in the wild pepper leaves were observed.(2) The volatile oil composition of different species of pepper leaves in the same orgin and the same picking time showed differences. The volatile oil composition of six varieties of pepper leaves was measured and 62 compounds were identified. The proportion of alkene compounds was the highest, accounting for 45.16%, followed by Ester compounds and alcohol compounds, with the values of 17.74% and 17.74%, respectively. A small amount of alkanes compounds, ketone compounds and acid compounds were also detected. The volatile oil of 6 species of pepper leaves contains alcohols, esters and alkene, containing the same kind of 18 compounds. The amount of compounds in Volatile oil of Fugu pepper leaves and No Thorns Hancheng was the highest. Volatile oil of other four pepper leaves showed the same kind of compounds, containing alcohols, esters, alkenes and hydrocarbons.(3) Blanching exhibited the important impact for the storage of pepper leaves. The optim um blanching parameters of pepper leaves by single factor test were determined that the temp erature was 100 oC, the optimum blanching time was 150 s, the ratio of solid to liquid was 1:20. Flavonoids content and total phenolic content of dried pepper leaves were significantly effe cted by hot air drying, vacuum drying and short-wave infrared drying. The optimum drying pa rameters of pepper leaves were determined by single factor experiment. Hot air drying temper ature was 55 oC, it took 2h on drying pepper leaves and the flavonoids and the total phenolic c ontents were 13.39 and 8.82mg/g respectively. Vacuum drying temperature was 65 oC and Va cuum degree was 0.07 Mpa, it took 12 h and the flavonoids and the total phenolic contents wer e 15.49 and 14.12mg/g respectively. Through three factors and three levels orthogonal test, th e optimum drying parameters of short wave infrared drying based on a single factor were that the wind speed was 5m/s, the temperature was 50 oC, and the power was 675 W, it took 2h and the flavonoids the total phenolic contents were 14.72 and 13.91 mg/g, respectively. The result s showed that hot air drying method needed short drying time and had low efficiency. Vacuu m drying had high efficiency but long drying time. Short-wave infrared drying exhibited the s hort time and high efficiency.