Chinese Rice Wine Research Articles

Development of a novel cooking wine with high-efficiency deodorizing capability via a rapid fermentation strategy

Chinese rice wine, when used as a cooking wine, has the important function of erasing fish and meat odours by evaporating odourous compounds and complementing the flavour of food. The objectives of the current study were to develop a short-term brewing process of rice wine and to evaluate the efficiency of deodorizing fish by preparing novel rice wine for cooking wine products. The technology of unilateral fermentation was applied in the rice wine brewing process, assisted by the pretreatment of enzymatic hydrolysis on rice. Following the optimization of enzymatic hydrolysis with ɑ-amylase, neutral protease, and glucoamylase, fermentation was conducted with Saccharomyces cerevisiae N85 and Lactobacillus plantarum B14. As a result, the primary fermentation period of rice wine was shortened from 15 days to 6 days. Furthermore, the preparation of cooking wine with sage, oregano, ginger, grape seed, and Chinese pepper was optimized through single-factor and response surface tests. The auxiliary material amount, extraction temperature, and extraction time were determined to be 1.61%, 35.8 °C, and 6 days, respectively. Finally, the cooking wine products exhibited 80.2%–88.9% deodorizing capability on 4 kinds of fish, which was more than 60% higher than that of common commercial cooking wines.

Effect of the joint fermentation of pyracantha powder and glutinous rice on the physicochemical characterization and functional evaluation of rice wine.

Pyracantha fortuneana, as a kind of wild plant resource for both medicine and food, has high nutrition and health‐care value. This study was to explore the effect of the joint fermentation of pyracantha powder and glutinous rice on the physicochemical and functional characterization of rice wine, aiming to improve the rice wine functional quality. As a result, a light dry rice wine fermented with P. fortuneana (PRW) was obtained using the fermentation technology of the Chinese rice wine. Although the contents of alcohol and protein in PRW were lower compared with the rice wine (RW) without adding pyracantha powder, the contents of sugar, ascorbic acid, total phenols, total flavonoids, and anthocyanins were higher in PRW. The analysis of volatile compounds by GC‐IMS showed that the contents of most aldehydes, alcohols, and esters increased in PRW. The quantification of organic acids and phenolic monomers indicated that most of the monomers determined were more abundant in PRW. Besides, the antioxidant capacity of PRW, including the scavenging rate of DPPH• and ABTS+•, was significantly stronger than that of RW. The bacteriostatic effect of the phenolic extracts from PRW was also observed obviously. It was expected to provide an effective way for the comprehensive utilization of P. fortuneana resource by producing a kind of nutritious and healthy pyracantha rice wine.

Effect of baking technique for rice wine production and the characteristics of baked rice wine.

Driven by the requirement to reduce the emission of wastewater in the brewing process, it is necessary to improve and innovate the fermentation technology of Chinese rice wine. In this study, the baking technique used to brew rice wine was explored. Rice wine was brewed based on baked glutinous rice undergoing different high-temperature stages, designated as baked rice wine (BRW1, BRW2 and BRW3). X-ray diffraction and Fourier transform infrared analysis revealed that baking treatment under 110 °C 0.5 h + 170 °C 30 min relatively changed the crystal properties and short-range molecular order of starch. Compared with the traditional rice wine (RW) from steamed rice, the alcohol content in BRWs was nearly twice that of RW, especially in BRW3. The contents of protein, ascorbic acid and total phenols in BRWs were significantly higher than that in RW. Besides, BRWs presented more abundance in the contents of volatile compounds, free amino acids and certain organic acids, including volatile esters and alcohols and 17 amino acids, which would give rice wine a pleasant aroma and a more comprehensive taste. Furthermore, analysis of the antioxidant capacity indicated a functional difference between RW and BRWs. It was feasible to produce rice wine using baked rice. The baking method allowed for several advantages, including the improvement of alcohol yield, fermentation efficiency, new typicality and stronger antioxidant capacity. This work is expected to provide a foundation for related research. © 2021 Society of Chemical Industry.

Structural Characterization of Peptides From Huangjiu and Their Regulation of Hepatic Steatosis and Gut Microbiota Dysbiosis in Hyperlipidemia Mice.

Hyperlipidemia is a chronic disorder that is difficult to cure and usually treated with long-term lipid-reducing drugs. Recent trends have led to the use of diet therapies or food-derived strategies in the treatment of such long-term diseases. The Chinese rice wine (huangjiu) contains a wide range of bioactive peptides that are produced during the multi-species fermentation process. To clarify the regulation effects of lipid metabolism and gut microbiota by huangjiu bioactive peptides, three huangjiu peptides were isolated, purified and characterized by hyper-filtration, macroporous resin, gel filtration separation and structural identification. Meanwhile, a mouse model of high-fat diet-induced hyperlipidemia was established to study the effects of huangjiu peptides on serum biomarker, hepatic metabolism and gut microbiota dysbiosis. Experimental results showed that huangjiu peptides T1 and T2 (HpT1, HpT2) treatment alleviated the increase in serum total cholesterol, triglyceride, low-density lipoprotein cholesterol levels and aberrant hepatic lipid accumulation in the high-fat diet-induced hyperlipidemia mice. Furthermore, HpT2 and HpT1 restored the α-diversity and structure of gut microbial community after hyperlipidemia-induced microbiota disturbance compared with simvastatin and HpT3. The administration of HpT2 and HpT1 regulated the microbiota-mediated gut ecology through alterations of characteristic taxa including Lactobacillus, Ileibacterium, Faecalibaculum and Alloprevotella by linear discriminant analysis effect size analysis. Collectively, our results offer new insights into the abilities of food-derived peptides on alleviation of high-fat diet-induced hyperlipidemia, hepatic steatosis and gut dysbiosis in mice.

Study on relationship between bacterial diversity and quality of Huangjiu (Chinese Rice Wine) fermentation.

Huangjiu (Chinese rice wine) is brewed in an open environment, where bacteria play an important role during the fermentation process. In this study, bacterial community structure and composition changes in the fermented mash liquid of mechanized Huangjiu, well‐fermented manual Huangjiu (wines of good qualities), and poorly fermented manual Huangjiu (wines of poor qualities: spoilage, high acidity, low alcohol content) in different fermentation stages from Guyuelongshan Shaoxing Huangjiu company were analyzed via metagenomic sequencing. And bacterial metabolic difference was analyzed via gene prediction of metabolic pathway enzymes. The results showed that the bacterial diversity degree was abundant, and the number of bacterial species in every sample was approximately 200–400. Lactic acid bacteria (LAB) dominated the bacterial community of Huangjiu fermentation, and lactobacillus was predominant species in well‐fermented Huangjiu while Lactobacillus brevis had an absolute dominance in spoilage Huangjiu. Further, gene prediction revealed that transformation of malate to pyruvate and lactate anabolism was more active in mash liquid of well‐fermented manual Huangjiu, while acetate accumulation was stronger in mash liquid of poorly fermented manual Huangjiu, which explained acidity excess reason in poorly fermented Huangjiu at gene level.

Aroma characteristics of traditional Huangjiu produced around Winter Solstice revealed by sensory evaluation, gas chromatography–mass spectrometry and gas chromatography–ion mobility spectrometry

Traditional Huangjiu (a kind of traditional Chinese rice wine) produced around Winter Solstice has higher quality and a more harmonious aroma than those produced during other periods. To determine the specific differences in aroma characteristics, sensory evaluation, gas chromatography–mass spectrometry (GC–MS) and gas chromatography–ion mobility spectrometry (GC–IMS) were used to analyze the volatile profiles of the traditional Huangjiu samples produced under different ambient temperature conditions. The sensory evaluation results showed that the aroma attributes of wheat, sweet, ester, alcoholic and sauce were stronger for the samples fermented near Winter Solstice than those for the other samples. GC–MS combined with heatmap analysis showed that with the decrease in average ambient temperature, the contents of esters such as diethyl succinate and ethyl butanoate gradually increased, and the contents of alcohols such as phenylethyl alcohol, 2-methylpropanol and 3-methylbutanol gradually decreased. Some key aroma compounds, such as ethyl butyrate (OAV: 97–151), nonanal (OAV: 189–200), ethyl octanoate (OAV: 859–1134) and ethyl phenylacetate (OAV: 307–353), were more abundant in the samples fermented near Winter Solstice than the other samples. The visualization of GC–IMS suggested that isoamyl acetate, 2-methylpropyl acetate, ethyl 3-methylbutyrate, and ethyl 2-methylbutanoate were enriched near Winter Solstice. Together, the results suggested that the traditional Huangjiu produced around Winter Solstice contained more flavor volatiles and had better aroma quality than those produced during other periods.

Kinetic modeling of ethyl carbamate formation from urea in Huangjiu during storage

Ethyl carbamate (EC) is a potential carcinogen widely found in various fermented foods and beverages, including Huangjiu (Chinese rice wine). Urea is the main precursor of ethyl carbamate in Huangjiu and the ethyl carbamate concentration increases gradually during storage. In this work, the changes of urea and EC content were investigated during the storage of Huangjiu under different conditions. The results indicated that urea hydrolysis is the dominant mechanism in urea consumption during storage. Then the kinetic models of urea consumption and EC formation were established based on the Arrhenius equation and Eyring equation, respectively. The prediction results of urea and EC concentrations based on these two models were consistent with experimental data, while the model based on the Eyring equation gave a better performance. The corresponding urea control indicators for Huangjiu with different alcohol concentrations under different storage conditions and specific EC benchmark limits can be calculated based on the model. The urea concentration of Huangjiu should be less than 2 mg/L to have a low risk for EC to exceed the standard of 100 μg/L after storage. Low-temperature storage can slow down and reduce the production of EC. These results are helpful to solve critical problems such as content prediction of urea and EC, condition control for storage and limit standards for EC in Huangjiu.

Composition and nutritional evaluation of amino acids in Mimai Qu rice wine

An amino acid analyzer was used to detect free amino acids (FAA) in Mimai Qu rice wines (SMW and DMW) and control wine samples (Chinese rice wine [CRW] and Japanese sake [JNS]). It was found that CRW had the highest total amino acid (TAA) content (~2814 mg/L), followed by SMW (~2509 mg/L) and DMW (~1474 mg/L), while JNS had the least (~917 mg/L). Amino acid ratio coefficient method (SRCAA), linear regression method, cluster analysis (CA) and principal component analysis (PCA) were used for evaluating the nutritional value of amino acids in wine samples, giving similar results. SMW had the highest nutritional value, followed by CRW and DMW and JNS.

Physicochemical properties of red millet: A novel Chinese rice wine brewing material

Red millet is a novel raw material for brewing Chinese rice wine. The physicochemical and structural properties of red millet (R1) were compared with those of five other brewing materials during pretreatment (soaking and steaming). Significant differences in physicochemical characteristics were found among raw grain varieties (p < .05). R1 had the highest protein content (18.36/100 g). The total acid and amino nitrogen contents of all grains showed a fluctuating upward trend during the soaking process. The reduction in setback viscosity of most grains after soaking indicated that soaking treatment slowed the retrogradation of starch. The grains changed into a gelatinized form with expanded pores after steaming. Further brewing might be beneficial due to the high acidity of soaking water (12.77 g/L), low setback value (336.50 cp), and large pore structure of R1 after pretreatment. Novelty impact statement In this study, some new findings were as follows: (1) the protein and fat content of red millet was the most outstanding; (2) red millet soaked water showed the highest total acid and amino nitrogen contents; (3) during steaming, grain morphological transformed into expanded porous structure. These results would improve our comprehending of the raw material characteristics of red millet, thereby providing theoretical guidance for the production and brewing of red millet wine.

Neuroprotective Effects of Chinese Rice Wine Fermented with Fu Brick Tea on H 2 O 2 ‐induced PC12 Cells

Chinese rice wine, as one of rice-based fermented foods with thousand-year history, is receiving more and more attention recently. Numerous new approaches of making supplementations have been created, such as fermentation with Lycium ruthenicum Murr., Zea mays L. ceretina kulesh, Diospyros lotus L. and so on. Fu brick tea is rich in antioxidant polyphenols like catechins, theaflavins and other bioactive compounds, which consequently linked to the protection abilities against chronic diseases, such as cancer, aging and cardiovascular disorders. Previously, we found CRW fermented with FBT (CRW-FBT) increased the population of yeasts and fungi, enhanced master extracellular enzyme activities, as well as ameliorated the profile of aroma compounds. Besides, it has been authenticated that CRW-FBT hydroalcoholic extracts acted a positive contributor to increase the content of polyphenols and improve the antioxidant activities, including scavenging free radicals and chelating oxidative metals. Therefore, we studied the neuroprotective effects of extracts on H2O2-induced apoptosis mediated by oxidative stress. PC12 cells exposed to H2O2 were utilized to construct a neurobiological oxidative damage cell model. The potential neuroprotective effects were investigated after the extracts pretreatment with different concentrations. The results showed that CRW-FBT hydroalcoholic extracts inhibited the decrease of cell viability induced by H2O2, in which the inhibition ratios of CRW-FBT treatments were much higher than that of CRW pretreatment. Flow cytometry and Western Blot were used to analyze the pathogenic mechanism of cell apoptosis. CRW-FBT significantly decreased the intracellular reactive oxygen species level in a dose-dependent manner, and prevented PC12 cells in oxidative stress from apoptosis through partially attenuating the cell cycle arrest, reversing the caspase-3 activity and enhancing the antioxidant enzyme activities. Moreover, the activities of superoxide dismutase, catalase and glutathione were increased when the concentration of the extracts increased from 50 to 400 μg/mL. CRW-FBT extracts rich in polyphenols reversed the mitochondrial membrane potential reduction and promoted lipid per-oxidization induced by H2O2. In conclusion, our findings highlighted that Fu brick tea was a high-quality functional food supplementation to participate in CRW fermentation for improving the capability of restoring neural dysfunction caused by oxidative damage.

Simultaneous Determination of Chiral Thiol Compounds and Monitoring of Dynamic Changes in Human Urine after Drinking Chinese Korean Ethnic Rice Wine.

Chinese Korean ethnic rice wine, a traditional fermented wine made from rice or corn, has antioxidant and antihypertensive activities. Although the determination of amino acids and other nutrients in rice wine has been reported, the existence of chiral thiol compounds has not been published in the literature. Therefore, we established a highly sensitive and selective ultrahigh-performance liquid chromatography-high-resolution mass spectrometry method for simultaneous determination and chiral separation of dl-Cys-GSH, dl-Cys-Cys, and dl-Cys-Hcy based on (R)-(5-(3-isothiocyanatopyrrolidin-1-yl)-5-oxopentyl) triphenylphosphonium derivatization. Three thiol diastereomers were completely separated on a YMC Triart C18 (2.0 × 150 mm, 1.9 μm) column with a resolution value (Rs) ≥ 1.52. The correlation coefficients were ≥0.9996, limit of detection was 2.40-7.20 fmol, and mean recoveries were 83.33-98.59%. Furthermore, fitted curves for dynamic changes in three kinds of chiral thiols in 10 human urine samples after drinking rice wine were drawn. Meanwhile, the metabolic changes in d/l-thiol compounds in human urine were investigated.

Concentrations of Total As and As Speciation in Chinese Rice Wine and Associated Risk Assessment in Main Producing Provinces

Concentrations of Total As and As Speciation in Chinese Rice Wine and Associated Risk Assessment in Main Producing Provinces

Microbial diversity and flavor of Chinese rice wine (Huangjiu): an overview of current research and future prospects

Chinese rice wine (Huangjiu), a typical representative of traditional fermented foods in China, is distinguished for its unique flavor. Microorganisms play the most important role in the formation of the unique flavor of Huangjiu. The complex flavor components in Huangjiu are closely related to the metabolism of various microorganisms during the traditional brewing. Therefore, understanding the influence of microbiota on the formation of flavor components in Huangjiu is conducive to the production of Huangjiu with high-quality flavor. In recent years, many scholars have conducted a large number of studies on the microbial community and flavor metabolites during the traditional brewing process of Huangjiu, with the help of high-throughput sequencing (HTS) and mass spectrometry-based metabolomics. This review mainly summarized the current study progress of the microbial diversity of fermentation starters (Qu) and brewing process of Huangjiu, and explored the potential relationship between the microbial community and the characteristic flavor formation of Huangjiu. Through the comparative analysis of literatures, we found that Huangjiu has strong regional characteristics due to the differences in raw materials, Qu and traditional brewing techniques. Dynamics of microbial composition during the traditional brewing of Huangjiu in different regions of China are quite different, making Huangjiu in each region have their own flavor characteristics. Therefore, revealing the relationship between brewing microorganisms and flavor characteristics of Huangjiu is helpful to the directional regulation of flavor quality. According to the current research status, it is proposed that in the future, emerging technologies such as multi-omics, artificial intelligence, and machine learning should be applied to further improve the accuracy of the analysis of microbial flora and flavor components in Huangjiu, so as to accurately reveal the relationship between the microbial community and the formation of characteristic flavor of Huangjiu. Afterwards, high-throughput screening of excellent functional strains from the traditional brewing system should be applied to the industrial production of Huangjiu, so as to improve the overall flavor quality and commercial value.

Peptides in Brewed Wines: Formation, Structure, and Function.

The traditional low-alcoholic beverages, such as grape wine, sake, and rice wine, have been consumed all over the world for thousands of years, each with their unique methods of production that have been practiced for centuries. Moderate consumption of wine is generally touted as beneficial for health, although there is ongoing debate for the responsible components in wine. In this review, the structural and functional characteristics, the formation mechanisms, and their health-promoting activities of peptides in three brewed wines, grape wine, Chinese rice wine (also called Chinese Huangjiu or Chinese yellow wine), and Japanese sake, are discussed. The formation of peptides in wine imparts sensorial, technological, and biological attributes. Prospects on future research, with an emphasis on the peptide characterization, formation mechanism, physiological activity, and molecular mechanisms of action, are presented.

Effect of enzymes addition on the fermentation of Chinese rice wine using defined fungal starter

A higher fermentation capability and quality of a rice wine was achieved, using mixed fungal (Rhizopus chinonsis R01, Asperigillus niger A20, Mucor pusillus M05 and Saccharomyces cerevisiae S10) starter fermentation of japonica rice supplemented with α-amylase (AM), glucoamylase (GAM) and acid protease (AP). Results showed that alcohol content, free amino acids (FAA) and volatile flavor substances concentrations were increased by 49.22%, 85.54%, and 25.71% compared with the control group respectively. To understand the role of enzymes during rice wine brewing, the effects of hydrolases on chemical and physical properties of cooking rice, on the yeast growth, enzyme productivity of molds were determined. Rice starch was hydrolyzed effectively by AM and GAM, the viscosity reduced significantly, the enzyme contact area expanded, which accelerated the further hydrolysis of japonica rice. Increase of hydrolysate promoted the fungi growth, while improved the ability of molds to produce enzymes. AP promoted the protease activity of M. pusillus M05 and A. niger A20, improved protein utilization, increased the content of FAA and formed higher level of flavor substances in rice wine. The results indicate that hydrolase addition can change the physic-chemical state of the mash to enhance microbial biotransformation and modify flavor metabolism.

ITRAQ-based proteomic analysis reveals the molecule mechanism of reducing higher alcohols in Chinese rice wine by nitrogen compensation

PurposeHigher alcohol is a by-product of the fermentation of wine, and its content is one of the most important parameters that affect and are used to appraise the final quality of Chinese rice wine. Ammonium compensation is an efficient and convenient method to reduce the content of higher alcohols, but the molecule mechanism is poorly understood. Therefore, an iTRAQ-based proteomic analysis was designed to reveal the proteomic changes of Saccharomyces cerevisiae to elucidate the molecular mechanism of ammonium compensation in reducing the content of higher alcohols.MethodsThe iTRAQ proteomic analysis method was used to analyze a blank group and an experimental group with an exogenous addition of 200 mg/L (NH4)2HPO4 during inoculation. The extracted intracellular proteins were processed by liquid chromatography-mass spectrometry and identified using bioinformatics tools. Real-time quantitative polymerase chain reaction was used to verify the gene expression of differentially expressed proteins.ResultsAbout 4062 proteins, including 123 upregulated and 88 downregulated proteins, were identified by iTRAQ-based proteomic analysis. GO and KEGG analysis uncovered that significant proteins were concentrated during carbohydrate metabolism, such as carbon metabolism, glyoxylate, and dicarboxylate metabolism, pyruvate metabolism, and the nitrogen metabolism, such as amino acid synthesis and catabolism pathway. In accordance with the trend of differential protein regulation in the central carbon metabolism pathway and the analysis of carbon metabolic flux, a possible regulatory model was proposed and verified, in which ammonium compensation facilitated glucose consumption, regulated metabolic flow direction into tricarboxylic acid, and further led to a decrease in higher alcohols. The results of RT-qPCR confirmed the authenticity of the proteomic analysis results at the level of gene.ConclusionAmmonium assimilation promoted by ammonium compensation regulated the intracellular carbon metabolism of S. cerevisiae and affected the distribution of metabolic flux. The carbon flow that should have gone to the synthesis pathway of higher alcohols was reversed to the TCA cycle, thereby decreasing the content of higher alcohols. These findings may contribute to an improved understanding of the molecular mechanism for the decrease in higher alcohol content through ammonium compensation.

Analysis of Flavor Components in HS-GC-IMS and Antioxidant Properties of Black &lt;i&gt;Lycium barbarum&lt;/i&gt; Rice Wine

Aim: Black Lycium barbarum rice wine is a kind of rice wine produced by the co-fermentation of black Chinese wolfberry and glutinous rice. In this study was to evaluate and compared the antioxidant activity and flavor substances of this type of rice wine with others. Methods: Through headspace gas chromatography-ion mobility spectroscopy (HS-GC-IMS), compared the flavor substances of black wolfberry rice wine, black rice wine, and common rice wine. Many components such as anthocyanins, total sugar, total acid, amino acid nitrogen, etc. in black Chinese wolfberry wine was observed. Results: It was found that the content of anthocyanins in black Chinese wolfberry rice wine increased continuously, approached the maximum value at 24 h, and decreased gradually after 24 h. The scavenging rates of •OH, DPPH, and ABTS in black wolfberry rice wine increased continuously after 24 h. The contents of total sugar, total acid, and amino acid nitrogen showed an increasing trend within 24 h and were close to the maximum. the flavor substances of black wolfberry rice wine and black rice wine were similar, but those of black wolfberry rice wine and common rice wine were different. Conclusion: From the perspective of more than 20 flavor substances, except for the fact that individual components such as butyl acetate, ethyl propionate, ethyl 3-methyl butyrate, and hexanol are much higher in black wolfberry rice wine than in black rice wine, the types and concentrations of other flavor substances are relatively similar, while some esters are absent or very low in common rice wine.

Impact of Pulsed Electric Fields Combined with Thermosonication on the Physicochemical Properties of Chinese Rice Wine

HighlightsThe TS-PEF diminished the color change compared to individual treatments.The concentration of Fe, Cr, and Ni increased after the treatments of PEF and TS-PEF.The volatile flavor compounds decreased after the treatment of TS and TS-PEF.Abstract. Chinese rice wine (CRW) is a traditional wine prevalent in East Asia. In current industrial production of bottled CRW, an additional thermal pasteurization is required at the bottling stage to extend the shelf life of the product, and this thermal treatment results in quality degradation and even carcinogen formation. In our previous studies, non-thermal technologies such as pulsed electric fields (PEF), thermosonication (TS), and their combination (TS-PEF) have been shown to significantly inactivate Saccharomyces cerevisiae in CRW as an alternative to thermal pasteurization of bottled wine. However, studies of their effects on the quality of CRW are very limited. In this study, we compared the physicochemical properties of CRW treated by pasteurization, PEF, TS, and TS-PEF. The results showed that the basic physicochemical indicators of CRW (total sugar, non-sugar solids, total acidity, amino acid nitrogen, and pH) did not change significantly after all these treatments. The TS-PEF treatment reduced the total color difference caused by the TS or PEF treatments. However, corrosion of the electrodes during PEF and TS-PEF treatment caused a significant increase in iron, chromium, and nickel concentrations. In addition, volatile flavor compounds, such as alcohols, esters, acids, and aldehydes, were reduced much more after TS and TS-PEF treatment than after pasteurization and PEF. Further research is needed on minimizing the negative impacts of these new technologies on the flavor of CRW in the context of effective sterilization. Keywords: Chinese rice wine, Metal ion, Physicochemical properties, Pulsed electric fields, Ultrasound, Volatile flavor compounds.

Application of mixed-culture with Lactobacillus brevis and Saccharomyces cerevisiae to Chinese yellow rice wine brewing for ethyl carbamate regulation

Co-culturing two or more species has recently been used in fermenting foods for product flavor or safety control. Ethyl carbamate (EC) is a potential carcinogenic compound presented in Chinese yellow rice wine which can be reduced by fermentation starters modification. In this work, the effect of Lactobacillus brevis (L. brevis) on EC in yellow rice wine fermentation with Saccharomyces cerevisiae (S. cerevisiae) was studied and an optimal mixed-culture fermentation method was constructed according to comparative analyses of EC concentration and fundamental quality. EC concentration could be further reduced by 68.4% at most through adding 108 cfu/L L. brevis during S. cerevisiae fermentation. L. brevis also had beneficial influence on hedonic quality of yellow rice wine. Meanwhile, the effect of gallic acid on EC formation in this mixed-culture fermentation system was elucidated. Unfortunately, the coexistence of gallic acid and L. brevis attenuated their inhibitory effect on EC formation.

Profiling the key metabolites produced during the modern brewing process of Chinese rice wine

The study quantitatively profiled 83 low-molecular-weight metabolites in the categories of alcohols, aldehydes, amino acids, esters, fatty acids, organic acids, and reducing sugars produced during the advanced brewing process of Chinese rice wine, using multiply chromatography and mass spectrum. In the primary fermentation, vigorous metabolisms were demonstrated by the production of ethanol at the level of 14% by volume, and the consumption of reducing sugars from the maximum level of 100 g/L to 20 g/L. Meantime, more than 70% of the contents of organic acids, fatty acids, higher alcohols, and aldehydes were formed. The metabolisms slowed down in the secondary fermentation, whereas 60% of the contents of amino acids and esters were accumulated in this stage. The nutrients, such as amino acids, organic acids, and reducing sugars reached 10 g/L, 5 g/L, and 3 g/L at the end of brewing, respectively. In terms of flavor and taste attributes to the brewed rice wine, the organoleptic activity value (i.e. the ratio of content to threshold value) was above 1 for 17 compounds, including six organic acids, namely acetic acid, citric acid, lactic acid, malic acid, succinic acid, and tartaric acid, four amino acids, namely cysteine, aspartic acid, glutamic acid, and lysine, three higher alcohols namely isoamyl alcohol, isobutanol, and phenethyl alcohol, three esters, namely ethyl acetate, ethyl butyrate, and ethyl hexanoate, and an aldehyde, namely benzaldehyde.