Abstract: In this study, the effect of sterilization methods on the microbial characteristics of rice cake was analyzed by investigating the trend of change in the total number of colonies during storage. The 16S rDNA V3-V4 region was sequenced by Illumina Miseq high-throughput sequencing technology. The effects of sterilization methods on the microbial community richness and diversity as well as the instrumental and sensory quality characteristics of rice cake were evaluated. The results showed that the total number of colonies in unsterilized and sterilized rice cake increased with storage time. The shelf lives of the untreated control, water-bath treatment and ethanol spraying groups were 3, 15 and 12 days, respectively. Alpha diversity analysis showed that sterilization had a great impact on the microbial richness and diversity of rice cake. In water bath treated rice cake, the dominant bacteria were Acinetobacter (40.49%), Pantoea (32.61%), and Salmonella (12.33%), while in the ethanol treated sample, the relative abundance of Pantoea and Salmonella was lower, and Acinetobacter (81.46%) and Microbacterium (10.74%) became the dominant bacteria. The Young’s modulus, firmness, toughness and masticatory power of rice cake gradually increased with storage time, whereas the elasticity, viscosity and sensory score showed a downward trend. More significant changes in these parameters were observed in the ethanol spraying group relative to the water bath treatment group. Collectively, it was concluded that water bath treatment is more suitable for maintaining the quality of rice cake during storage.

Key words: rice cake; water bath treatment; ethanol spraying; quality; microbial diversity