Metabolomic Profiles of Aspergillus oryzae and Bacillus amyloliquefaciens During Rice Koji Fermentation.
Rice koji, used early in the manufacturing process for many fermented foods, produces diverse metabolites and enzymes during fermentation. Using gas chromatography time-of-flight mass spectrometry (GC-TOF-MS), ultrahigh-performance liquid chromatography linear trap quadrupole ion trap tandem mass spectrometry (UHPLC-LTQ-IT-MS/MS), and multivariate analysis we generated the metabolite profiles of rice koji produced by fermentation with Aspergillus oryzae (RK_AO) or Bacillus amyloliquefaciens (RK_BA) for different durations. Two principal components of the metabolomic data distinguished the rice koji samples according to their fermenter species and fermentation time. Several enzymes secreted by the fermenter species, including α-amylase, protease, and β-glucosidase, were assayed to identify differences in expression levels. This approach revealed that carbohydrate metabolism, serine-derived amino acids, and fatty acids were associated with rice koji fermentation by A. oryzae, whereas aromatic and branched chain amino acids, flavonoids, and lysophospholipids were more typical in rice koji fermentation by B. amyloliquefaciens. Antioxidant activity was significantly higher for RK_BA than for RK_AO, as were the abundances of flavonoids, including tricin, tricin glycosides, apigenin glycosides, and chrysoeriol glycosides. In summary, we have used MS-based metabolomics and enzyme activity assays to evaluate the effects of using different microbial species and fermentation times on the nutritional profile of rice koji.
Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea. daeun237@naver.com.
Da Eun
da E
Lee
Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea. duly123@naver.com.
Sunmin
S
Lee
Foods Research Institute, CJ CheilJedang Corp., Suwon 16495, Korea. eunseok.jang@cj.net.
Eun Seok
ES
Jang
Foods Research Institute, CJ CheilJedang Corp., Suwon 16495, Korea. hyewon.shin@cj.net.
Hye Won
HW
Shin
Foods Research Institute, CJ CheilJedang Corp., Suwon 16495, Korea. bs.moon@cj.net.
Byoung Seok
BS
Moon
Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea. chlee123@konkuk.ac.kr.
Choong Hwan
CH
Lee
D000596:Amino Acids / Q000378:metabolism; D001236:Aspergillus oryzae / Q000737:chemistry / Q000378:metabolism*; D000069977:Bacillus amyloliquefaciens / Q000737:chemistry / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D005285:Fermentation; D005419:Flavonoids / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D008246:Lysophospholipids / Q000378:metabolism; D055432:Metabolomics; D012275:Oryza / Q000737:chemistry / Q000378:metabolism*; D000516:alpha-Amylases / Q000737:chemistry / Q000378:metabolism*
D000596:Amino Acids; D005419:Flavonoids; D008246:Lysophospholipids; D000516:alpha-Amylases
antioxidant activity; enzymatic activity; fermentation; metabolomics; microbe; rice koji