In this study, liquid-liquid microextraction coupled with gas chromatography with hydrogen flame ionization detection (LLME-GC-FID) and orthogonal partial least squares-discriminant analysis (OPLS-DA) were integrated to track and monitor the contents of furfural and furfuryl alcohol in the raw materials, Daqu, stacking fermented grains, pit fermented grains, upper and lower steamer fermented grains, and distillates, which were collected at the key steps of the brewing process of sauce-flavor Baijiu. The results showed that the spatial and temporal distribution of furfural and furfuryl alcohol during the brewing process of sauce-flavor Baijiu varied significantly. The contents of furfural and furfuryl alcohol increased at first and then decreased at the Daqu-making stage. The contents of furfural and furfuryl alcohol showed an upward trend at the stacking fermentation stage. During the pit fermentation stage, the content of furfural decreased while the content of furfuryl alcohol increased. During the distillation process, the content of furfural increased, while the content of furfuryl alcohol decreased from the upper steamer to the lower steamer. The contents of furfural and furfuryl alcohol showed an increasing trend at the alcohol extraction stage. The distribution of furfural during the brewing process was generally lower layer > middle layer > upper layer. The distribution of furfuryl alcohol was middle layer > lower layer > upper layer at the stacking fermentation stage, and lower layer > middle layer > upper layer at the cellar fermentation stage and the distillation stage. Traceability analyses showed that furfural and furfuryl alcohol were mainly derived from Daqu powder, rice husk, and the late distillation stage. The formation mechanism of furfural during the brewing process of sauce-flavor Baijiu was attributed to microbial action, sugar degradation, and Maillard reaction under high temperature and acidic conditions. This study provides theoretical guidance for the reduction and control of furfural and furfuryl alcohol during the brewing of Baijiu, and provides a scientific basis for regulating the quality and safety of Baijiu.
WU Q, XU Y, CHEN L. Diversity of yeast species during fermentative process contributing to Chinese Maotai-flavour liquor making[J]. Letters in Applied Microbiology, 2012, 55(4): 301-307. DOI:10.1111/j.1472-765X.2012.03294.x.
ABRAHAM K, GÜRTLER R, BERG K, et al. Toxicology and risk assessment of 5-hydroxymethylfurfural in food[J]. Molecular Nutrition & Food Research, 2011, 55(5): 667-678. DOI:10.1002/mnfr.201000564.
CAPUANO E, FOGLIANO V. Acrylamide and 5-hydroxymethylfurfural (HMF): a review on metabolism, toxicity, occurrence in food and mitigation strategies[J]. LWT-Food Science and Technology, 2011, 44(4): 793-810. DOI:10.1016/j.lwt.2010.11.002.
WU X, LIU J, WANG Q, et al. Research progress on the effect of Bacillus on flavor substances of Maotai flavor Baijiu[J]. Food Science and Technology, 2023, 43: e101422. DOI:10.1590/fst.101422.
DU Y K, XIN W, XIA Y, et al. Analysis of fermentation control factors on volatile compounds of primary microorganisms in Jiangflavor Daqu[J]. Journal of Food Biochemistry, 2022, 46(10): e14277. DOI:10.1111/jfbc.14277.
XU Y Q, WU M Q, NIU J L, et al. Characteristics and correlation of the microbial communities and flavor compounds during the first three rounds of fermentation in Chinese sauce-flavor Baijiu[J]. Foods, 2023, 12(1): 207. DOI:10.3390/foods12010207.
GONG M, ZHOU Z L, LIU S P, et al. Formation pathways and precursors of furfural during Zhenjiang aromatic vinegar production[J]. Food Chemistry, 2021, 354: 129503. DOI:10.1016/j.foodchem.2021.129503.
HUANG H M, CHEN J B, ZHENG M F, et al. Precursors and formation pathways of furfural in sugarcane juice during thermal treatment[J]. Food Chemistry, 2023, 402: 134318. DOI:10.1016/j.foodchem.2022.134318.
WANG X Q, CUI W W, GUO W T, et al. Separation techniques for manufacturing fruit spirits: from traditional distillation to advanced pervaporation process[J]. Comprehensive Reviews in Food Science and Food Safety, 2024, 23(1): e13278. DOI:10.1111/1541-4337.13278.13278.
ZHANG H X, WANG L, TAN Y W, et al. Effect of Pichia on shaping the fermentation microbial community of sauce-flavor Baijiu[J]. International Journal of Food Microbiology, 2021, 336: 108898. DOI:10.1016/j.ijfoodmicro.2020.108898.
NAMLI S, SUMNU S G, OZTOP M H. Microwave glycation of soy protein isolate with rare sugar (D-allulose), fructose and glucose[J]. Food Bioscience, 2021, 40: 100897. DOI:10.1016/j.fbio.2021.100897.
CERNY C, BRIFFOD M. Effect of pH on the Maillard reaction of[13C5]xylose, cysteine, and thiamin[J]. Journal of Agricultural and Food Chemistry, 2007, 55(4): 1552-1556. DOI:10.1021/jf062874w.
ZHU C T, CHENG Y X, ZUO Q C, et al. Exploring the impacts of traditional crafts on microbial community succession in Jiangflavored Daqu[J]. Food Research International, 2022, 158: 111568. DOI:10.1016/j.foodres.2022.111568.
JIN Y, LI D Y, AI M, et al. Correlation between volatile profiles and microbial communities: a metabonomic approach to study Jiang-flavor liquor Daqu[J]. Food Research International, 2019, 121: 422-432. DOI:10.1016/j.foodres.2019.03.021.
HAO F, TAN Y W, LV X B, et al. Microbial community succession and its environment driving factors during initial fermentation of Maotai-flavor Baijiu[J]. Frontiers in Microbiology, 2021, 12: 669201. DOI:10.3389/fmicb.2021.669201.
PEREIRA V, ALBUQUERQUE F M, FERREIRA A C, et al. Evolution of 5-hydroxymethylfurfural (HMF) and furfural (F) in fortified wines submitted to overheating conditions[J]. Food Research International, 2011, 44(1): 71-76. DOI:10.1016/j.foodres.2010.11.011.
WANG X X, FAN W L, XU Y. Comparison on aroma compounds in Chinese soy sauce and strong aroma type liquors by gas chromatography-olfactometry, chemical quantitative and odor activity values analysis[J]. European Food Research and Technology, 2014, 239(5): 813-825. DOI:10.1007/s00217-014-2275-z.
DELBECQ F, WANG Y T, MURALIDHARA A, et al. Hydrolysis of hemicellulose and derivatives-a review of recent advances in the production of furfural[J]. Frontiers in Chemistry, 2018, 6: 146. DOI:10.3389/fchem.2018.00146.
ZHU C T, CHENG Y X, SHI Q L, et al. Metagenomic analyses reveal microbial communities and functional differences between Daqu from seven provinces[J]. Food Research International, 2023, 172: 113076. DOI:10.1016/j.foodres.2023.113076.
WANG L, WANG Y Y, WANG D Q, et al. Dynamic changes in the bacterial community in Moutai liquor fermentation process characterized by deep sequencing[J]. Journal of the Institute of Brewing, 2015, 121(4): 603-608. DOI:10.1002/jib.259.
MARCHAND S, DE REVEL G, VERCAUTEREN J, et al. Possible mechanism for involvement of cysteine in aroma production in wine[J]. Journal of Agricultural and Food Chemistry, 2002, 50(21): 6160-6164. DOI:10.1021/jf025604w.
JAIN K K, DEY T B, KUMAR S, et al. Production of thermostable hydrolases (cellulases and xylanase) from Thermoascus aurantiacus RCKK: a potential fungus[J]. Bioprocess and Biosystems Engineering, 2015, 38(4): 787-796. DOI:10.1007/s00449-014-1320-4.