LI Zhe, FENG Haiyan, HE Jie, HE Junjun, SONG Changmei, ZHOU Mimi, ZHAO Tengfei, JIANG Zeyuan, YAN Genglong, ZHANG Zhang, GAN Guangdong, HE Siqi, SONG Lulu
In order to reveal the causes and characteristics of Hongxinqu produced during the fermentation of high-temperature Daqu, using sauce-flavor (Jiangxiangxing) Hongxinqu as research object, the sensory, physicochemical and microbial indicators of Hongxinqu were analyzed by conventional methods, and the red pigment-producing strains were screened and identified by dilution coating plate method, morphological observation and molecular biology technology. The results showed that the surface of Hongxinqu covered with gray-white hyphae, which was well dressed without cracks, the color of Hongxinqu was relatively uniform, light yellow, and the gloss was better than that of high-temperature Daqu. The cross section of Hongxinqu had excellent hyphal growth, and there was a significant red stain in the center of Hongxinqu. The skin of the Hongxinqu was relatively thick, about 0.8 cm, with complex Daqu flavor, the sauce flavor was not obvious, and there was a faint musty smell in the center of the Hongxinqu, slightly with ester fragrance. The moisture of Hongxinqu was 12.61%, the acidity was 2.07 mmol/L, both of which were higher than high-temperature Daqu, the starch content was 48.77%, which was lower than high-temperature Daqu. The count of yeast, molds and bacteria in the center of Hongxinqu were 6.9×103 CFU/g, 8.0×104 CFU/g and 2.8×105 CFU/g, respectively, and in the center of high temperature Daqu were 3.6×103 CFU/g, 2.5×104 CFU/g and 3.5×106 CFU/g, respectively. Three strains of red pigment-producing fungi (numbered as B1, B2, A1) were screened out from Hongxinqu, and which were identified as Monascus rutilus, Monascus aurantiacus and Cystobasidium, respectively. This study could provide a scientific basis for initially revealing the cause of Hongxinqu formation and screening and breeding microbial resources with potential theoretical and application value from it.
