Contrast Between Hot-air Drying Of Chili Under Constant Temperature And That Under Gradedand Controlled Temperature

The vitamin c content of chili is the richest among vegetables. Chili is also rich in vitaminβ, folate, capsaicin, phosphorus, calcium, iron etc. Dried chili has always been our country’s famous specialty, and also major traditional export product, and both its production and trade are in tops in the world. With the improvement of people’s living standard, a higher demand is put forward for chili drying process. The harvest season of chili, in China, is also rainy season, and that makes the drying and storage of chili of the processing problems to be solved. As the main condiment, dried chili is in the consumption all year round, but production season in field is limited, so need to dehydrate fresh chili to adjust the contradiction between the supplies of the short season. Therefore, research the better chili drying process to improve people’s living standards, increase farmers’income has important practical significance.At present, the chili hot-air drying research is almost under constant temperature, and is not hot-air drying research under controlled temperature or compared study under constant temperature and controlled temperature. The result of contrast between hot-air drying of Chinese prickly ash under constant temperature and that under controlled temperature shows that comprehensive evaluation result under controlled temperature is better than the result under constant temperature. Therefore, there is some academic value to comparative study between hot-air drying of chili under constant temperature and that under controlled temperature.The subject determined the chili hot-air drying test program, and select the air temperature and wind speed as test factors, and made experimental research between hot-air drying of chili under constant temperature and that under controlled temperature, and the experiment has been done on the thin-layer drying test bed, and processing and analysis the test data using data processing software such as EXCEL, Matlab, SPSS and so on, and obtained the experimental results. The results show that:1) Under both constant temperature and controlled temperature hot-air drying conditions, the drying characteristic curves of chili change obviously as the air temperature and the wind speed increases.2) Comparative analysis on the three commonly used drying models, and obtained that Page model can express chili hot-air drying characteristics of both constant tempetature and controlled temperature.3) Fitting analysis chili drying characteristic curves of different conditions by Matlab software, and obtained fitting function expression of different conditions, and drawn a comparison chart of the measured curve and fitting curve.4) Under both constant temperature and controlled temperature hot-air drying conditions, the quality of dried chili is similar. However, the comprehensive evaluation result of the latter is better than the former.5) By variance analysis for the comprehensive evaluation result of different conditions, we can see that the impact of hot-air temperature on dried chili composite indicator is very significant, and the impact of wind speed is not significant.The optimum process of chili hot-air drying is that the first temperature is 45℃, and after 150 minutes the temperature is rised quickly to 60℃, and the wind speed is 1.2m/s, under the controlled temperature hot air drying conditions, and the total drying time is 413 minutes.