Preliminary Study On Pungency Degree Of Dishes In Sichuan,Hubei,Zhejiang And The Impact Of Geographical And Climatic Factors

Based on the Chinese menu data and on-the-spot investigation, this study quantitatively analyzed the spicy characteristics of dishes in Sichuan, Hubei and Zhejiang Provinces, using high performance liquid chromatographic detection method. With the quantitative analysis results, the reasons behind the difference in regional spicy food were analyzed. People in different regions have different eating habits for spicy food and this difference was related to geographical environment, climatic conditions, disease and health condition and other factors. This research expects to lay a foundation for the effect study of geographical and climatic factors on regional food spicy differences. The main results were as follows:1. Sichuan Dazhou, Sichuan Zigong, Sichuan Chengdu, Sichuan Guangyuan, Hubei Xiangyang, Hubei Yichang Hubei Wuhan Hubei Huangshi, Zhejiang Shaoxing, Zhejiang Hangzhou, Zhejiang Ningbo, Zhejiang Wenzhou were chosen as sampling locations, collecting 300 local representative dishes from these locations.2. Capsaicin and dihydrocapsaicin in dishes were extracted by ultrasonic method and methanol-tetrahydrofuran(1:1) as solvent. The regression equation of capsaicin standard curve was Y=6636.7X+1221 and correlation coefficient R2=0.9999. The regression equation of dihydrocapsaicin standard curve was Y=6338.9X-3758 and correlation coefficient R2=0.9999. The response-surface analysis was adopted to optimize the process condition based on single factor experiment, the optimum condition for capsaicinoids extraction was obtained as follows: time of 50 minutes, temperature under 59℃, solid- liquid ratio of 1:7(g/m L), mentioned two times. Under the optimal condition, the content of capsaicinoids in dish was 1.352g/kg.3. Fast and efficient method for the determination of main spicy ingredients in dishes was established by optimizing the detection chromatographic condition according to GB/T 21266-2007, the reliability of method was measured with accuracy, stability and recovery tests. The chromatographic conditions were found to be as follows: column was Venusil XBP-C18(4. 6 mm × 250 mm, 5 μm), the mobile phase was methanol:water(70:30) with the flow rate 0.8 m L/min and the UV detection wavelength was set at 280 nm, this method was accurate, convenient and reproducible.4. The contents of spicy ingredients in dishes collected from Sichuan, Hubei and Zhejiang were detected to analyze the piquancy characteristics. In 100 Sichuan dishes,74% used chili with the spicy degree of 5.18. The proportion of Hubei dishes that contained chilii was 45%, and the spicy degree was 2.18. 13% Zhejiang dishes contained chilii with a spicy degree of 0.143.5. Differences in diet was mainly affected by geographical conditions and climatic factors, including: altitude、average temperature、average relative humidity、average precipitation、sunshine duration、annual temperature range、average wind speed. According to available statistics, the relationship between piquancy degree with geographical conditions and climatic factors was analyzed through multivariate statistical analysis. Correlation regression equation was: Y=32.856-0.003X5-7.565X6(Y: Spiciness of dishes in different regions; precipitation in different regions; sunshine duration in different regions), the initial finding was that sunshine duration has the greatest impact on geographical differences in piquancy degree of Sichuan, Hubei and Zhejiang.