A preliminary study of the calcification reason of pit mud in Chinese Strong-flavour liquor

Abstract Pit mud play a key role in the brewing process of Chinese Strong-flavour liquor. In this study, the organic acids and metal ions was determinated by Ion Chromatograph and Inductively Coupled Plasma Mass Spectrometry, respectively. The diversities and structures in pit mud were analyzed by using high-throughput sequencing based on Illumina Miseq platform. The results showed that the lactic acid in calcified pit mud was about 10 times higher than quality pit mud, and the calcium ions was about 20 times higher than quality pit mud. It could found a strange phenomenon, the calcified pit mud had more pyruvic acid and quality pit mud basically does not had this kind of material. The data analysis shown that the pit mud were detected prokaryotes 908 strains and the eukaryotes 226 strains. It was found that the Lactobacillus and Prevotella in calcified pit mud (the total of both increase 11 times) had a higher percentage. It can be guess that the lactic acid and metal ions would form lactic acid salt compounds and those compounds could affect the growth and reproduction of microbes in pit mud. This study provided a good comparison of physical and chemical properties between the calcified pit mud and the quality pit mud, which was significant for the maintenance of pit mud and the quality of liquor. Because of the first study for pit mud by using high-throughput sequencing, it could provide theoretical basis for improving microbes in pit mud.