Effects of Natural Sun and Hot Air Drying on the Physicochemical Properties, Microbiome, and Flavor Profile of Rugao Sausage

Abstract

This study investigated the mechanisms by which different drying methods determine the quality of Rugao sausage, with a particular focus on the mediating role of the microbial ecosystem. Sausages subjected to traditional natural sun drying (NDS) and hot air drying (HDS) were compared regarding their physicochemical properties, microbial community dynamics, and volatile flavor profiles. Although HDS significantly reduced moisture content and total bacterial counts, potentially prolonging shelf life, it concurrently accelerated lipid oxidation, which adversely affected quality attributes. Critically, high-throughput sequencing revealed that the drying method fundamentally shaped the microbial community structure. NDS exhibited higher microbial evenness and diversity, fostering a balanced ecosystem dominated by Streptococcus (18.81%) and Acinetobacter (15.21%). In contrast, HDS, while showing higher species richness, was characterized by a distinct compositional shift, predominantly comprising Streptococcus (35.30%), Macrococcus (15.72%), and Rothia (10.17%). This divergence in the microbial ecosystem directly translated to distinct flavor outcomes: the concentrations of key volatile flavor compounds were significantly higher in NDS than in HDS. These findings indicate that NDS more effectively promotes the formation and retention of flavor compounds by enriching a more diverse and metabolically active microbial community. This research provides a scientific basis for optimizing industrial production processes by elucidating the causal chain linking drying technique, microbial ecology, and final product quality.