Analysis of Hong Qu Quality and Microbial Taxa Based on Physicochemical Indicators and MiSeq High-throughput Sequencing Technology

In this study, to reveal the physicochemical properties and microbial taxa of Hong Qu produced in Shandong, China three Hong Qu samples were collected from a Shandong Qu-making company, and based on the determination of their physicochemical indexes and fermentation characteristics, the microbial taxa were resolved using MiSeq high-throughput sequencing technology, and the Bacillus and lactic acid bacteria contained in them were isolated and identified. The results showed that the moisture content of the three Hong Qu samples ranged from 8.27% to 10.30%, acidity ranged from 1.0 to 1.3 mmol/10 g, amino acid nitrogen content ranged from 131.65 to 172.76 mg/100 g, saccharification power ranged from 476 to 764 U/g, esterification power ranged from 331 to 548 U/g, and fermentation power, liquefaction power and alcoholization power were less than 10 U/g. The bacterial taxa of Hong Qu were mainly composed of Weissella (41.93%) and Acetobacter (9.99%), and the fungal taxa were mainly composed of Pichia (55.83%) and Monascus (21.24%), where the correlation between bacteria and alcoholization power was significant, and while the correlation between fungi and saccharification power was significant (P<0.05). Bacillus siamensis (B. siamensis) accounted for 79.17% of the Bacillus isolates and Pediococcus pentosaceus (P. pentosaceus) accounted for 55.55% of the lactic acid bacteria isolates. This shows that the Bacillus and lactic acid bacteria taxa included in this study mainly consisted of B. siamensis and P. pentosaceus, and the low content of Monascus and high content of Pichia might be the main reason for their low saccharification power.