Study On Volatile Compound And Aroma Characteristics Of Chinese Red Pepper

Red pepper,a kind of cash crop for food and medicine,has been cultivated for more than 2,000 years and is widely distributed in East,North,Central,Southwest and Northwest China.Affected by the ecological environment,the aroma characteristics of pepper have obvious differences from different producing areas,leads to a large difference in application value and price.In order to study the aroma characteristics of red pepper from different producing areas,68 samples were collected from five main producing areas in Southwest,Northwest,North,East and central of China.Flash GC electronic nose and gas chromatography-mass spectrometry were used to characterize the overall aroma pattern of the samples and classify the samples from different producing areas.On this basis,11samples were selected to analyze their composition?volatile substances and aroma-active substances?and perception characteristics respectively,which enriched the basic data of Chinese red pepper aroma,and clarified the material pattern classification,aroma composition and sensory characteristics,in order to provide technical basis for pepper quality evaluation and targeted application.The results were as follows:1.These 68 samples can be divided into three classifications.The first class of red pepper comes from southwestern China including Gansu,Qinghai and Shaanxi Baoji and Maoxian,a city of Sichuan.Class two is north,east and central China such as Hebei,Henan,Shanxi and Shandong and Hancheng,a city of Shaanxi.Class three is coming from southwest area including Yunnan,Sichuan.There were differences in Heracles?response characteristics of the three types of pepper,mainly in the response points 22.97-1,26.29-1,35.90-1,22.34-2 and 37.60-2.The response value of the first type of area at the points22.97-1 and 22.34-2 was less than 10%,while the other two types of regional response values both are greater than 10%.At the points 26.29-1,the value of the first type samples was less than 20%,while the other two types of regional response values both are greater than 20%.The value of the first type of area at the points 35.90-1 and 37.60-2 was greater than 10%,while the other two types of regional response values both are less than 10%,and the response of the third type of area are between 5%and 10%.2.The total volatile matter content ranged from 17.36 to 198.87 mg/g.There was a significant difference in the total amount of volatile oil in different producing areas?P<0.05?.The content of the first type was 85.71-123.68 mg/g,the content of the second types was17.36-74.16mg/g,and content of the third types was 45.30-65.60 mg/g.A total of 65 volatile substances were detected in pepper from 11 different producing areas.The main volatiles?content higher than 10%?included Linalyl acetate?D-Limonene??-Terpineol?Eucalyptol?Sabinene?Linalool and?-Myrcene.The contents of seven main substances were different in different habitats.The total volatile substances were higher than 70%in the first and third categories,and the main volatile substances were between 50%and 70%in the second category.The volatile substances are mainly olefins,alcohols and esters,accounting for more than 96%of the total content of the substances.The volatile constituents of different producing areas are different.The first type shows the characteristics of balanced content of olefins and alcohols and high content of esters,the second type shows the characteristics of low esters and middle alcohols in high olefins,and the third type shows the characteristics of low alcohols.3.A total of 17 aroma active substances?FD?1?were identified from 11 samples?9olefins,3 alcohols,2 esters,1 aldehydes,1 ketones and Linalool oxide?.The number of these substances is nine,which?FD>128?contributed highly to the aroma of pepper,including Sabinene,D-Limonene,Linalool,trans-Sabinene hydrate,Neo-allo-ocimene,Citronellal,Terpinen-4-ol,?-Terpineol,and Linalyl acetate.The total content of aroma active substances in 11 samples ranged from 9.41 to 14.14 mg/g,accounting for 53.18%-92.29%of the total content.The proportion of aroma active substances was higher than 80%in the first and third category,while the proportion of aroma active substances was between 50%and 70%in the second category.4.The aroma concentration ranged from 707 to 3182 O_UEm^-3 in 11 samples from different habitats,and there was no significant correlation among aroma concentration,total volatile matter content and total aroma active substance content.According to the intensity of aroma,the samples from different regions were divided into three categories:Handan and Baoji which belonged to low-intensity samples with aroma concentration of 707-1105O_UEm^-3;Linxia,Laiwu,Anyang,Hancheng and Yuncheng which belonged to medium-intensity samples with aroma concentration of 1591-2121 O_UEm^-3;Wudu,Ninglang,Maoxian and Hanyuan,which belonged to high-intensity samples,the aroma concentration was 2475-3182 O_UEm^-3.5.There were significant differences in aroma characteristics among samples from different origins.Linxia samples showed moderate intensity and strong aroma of pepper,lemon and minty;Handan samples showed low intensity and strong aroma of pepper,green and citrus;Laiwu pepper belonged to moderate intensity,with obvious aroma characteristics of pine,minty,citrus and lemon.Yuncheng sample showed moderate intensity and obvious aroma of pepper,pine and minty;Hancheng sample showed middle strength and peculiar aroma of pine,citrus and pepper;Ninglang pepper was a sample with outstanding aroma characteristics such as high strength lemon and minty;Hanyuan sample belonged to high strength of citrus,lemon and pepper.