Quality Analysis of Key Nodes of Natural Drying Chilis in Xinjiang Region

Objective: Xinjiang is one of the main producers and exporters of dried chilies in China. Dried chilies in Xinjiang are mainly dried by natural drying methods, however, relying too much on experience and lacking scientific theoretical guidance, the dried products are prone to problems such as breakage and mold. Therefore, it is urgent to monitor the quality changes in the drying process of chilies and to standardize the technical process of dried chili production. Methods: The Honglong series of rambutan peppers (Honglong 18 and Honglong 23), grown on a large scale in Xinjiang, were selected. Three key points in the natural drying process have been selected: Flattening (starting point of drying), gathering of small piles and gathering of large piles (end point of drying). The study followed four batches and monitored changes in the quality of chilies, including moisture content, water activity, seed to flesh ratio, sugar content, total phenolic content, antioxidant capacity, color value, texture, moldiness and microbiological composition. Results: The moisture content of the chilies at the end of drying was below 13%. The drying process significantly reduced the sugar content, total phenolic content and antioxidant capacity of the chilies (P<0.05) and significantly increased the color value of the chilies (P<0.05), eventually reaching around 29. The variety of chilies, the time of harvest and the length of drying would all affect the quality of the finished product. The dominant fungi in moldy chilies were Aspergillus and Rhizoctonia spp. Conclusion: The moisture content of chilies at the beginning of drying was the key factor affecting the quality of chilies during drying. It was recommended to use "hanging and drying" to reduce the initial moisture content, improve the drying efficiency, enhance the quality and reduce the mold rate. This study would provide a theoretical basis for the development of the "Natural Drying Technology for Chilies in Xinjiang".