Search

Lactic acid bacteria can be inoculated at different stages of alcoholic fermentation during winemaking' but the influence of inoculation timing of indigenous lactic acid bacteria on wine is not well defined. The aim of this study was to investigate the influence of inoculation timing of Chinese indigenous lactic acid bacteria and commercial yeast on physiochemical parameters and the color of synthetic red grape juice. Three selected lactic acid bacteria 6-20' GZC3 and V22 were used to ferment the synthetic medium with Saccharomyces cerevisiae CECA. Two inoculation strategies were applied in the fermentation' including simultaneous and sequential inoculation' with single fermentation as the control. The sequential inoculation includes inoculating Saccharomyces cerevisiae 2 and 4 days prior to inoculating lactic acid bacteria and vice versa. The fermentation process was monitored by regularly measuring residual sugar' malic acid' and the colony numbers of both yeast and bacteria. After completion of fermentation' basic physiochemical parameters such as total acidity' volatile acidity' and pH were measured. Following this' total polyphenols and anthocyanins were determined by the Forlin phenol method and pH-differential method' respectively. Color parameters were then obtained through CIELab color space. Further, the correlation between color parameters and anthocyanin content was analyzed to evaluate wine color characteristics. Finally, Adobe Photoshop CS6 software was used to intuitively simulate the color of each wine sample. Results showed that there were significant differences in fermentation characteristics of simulated wine fermented by different inoculation strategies and these were strain-dependent. All strain pairs successfully completed alcohol fermentation (AF) in approximately 15 days. Malolactic fermentation (MLF) occurs simultaneously with or earlier than AF, depending on the inoculation timing of lactic acid bacteria. Not surprisingly, MLF was completed together with AF, or shortly after the depletion of residual sugar. Early inoculation of lactic acid bacteria was more conducive to MLF, whilst inoculation of yeast prior to lactic acid bacteria was more beneficial to AF. Particularly for CECA/6-20 mixed fermentations, AF took 2-4 days less when inoculating CECA prior to the inoculation of 6-20 compared to the rest inoculation strategies. Simultaneous inoculation of both S. cerevisiae and lactic acid bacteria had no significant effect on overall fermentation duration. The basic physicochemical parameters of all wine samples met the relevant national wine standards. In addition, the total phenol content and total anthocyanin level of most fermentation groups decreased significantly, and there was a significant correlation between these two parameters, though their correlation to CIELab color parameters was weak. With regard to wine colors, sequential inoculation resulted in darker colors compared to the simultaneous inoculation group. Interestingly, wine color was also species-specific, in particular, samples inoculated with Oenococcus oeni GZC3 were generally darker than that inoculated with Lactobacillus plantarum V22 and 6-20. To conclude, this study clearly proved that our selected indigenous lactic acid bacteria strains were compatible with the commercial yeast CECA regardless of inoculation timing, thereby reducing the overall fermentation duration. Co-fermentation of yeast and bacteria would impact certain physiochemical parameters of wine. This study provides theoretical support and reference for efficient local production of high-quality red wine as well as helps promote the wide application of indigenous wine in China. [ABSTRACT FROM AUTHOR]

“Green-covering” Tuqu (TQ), as one of Xiaoqu, is a special fermentative starter (also known as Jiuqu in Chinese) that originated in southern China and is characterized by a layer of green mold covering (Aspergillus clavatus) the surface and (sometimes) with a red heart. It plays a vital role in producing light-aroma-type Baijiu (LATB). However, to date, the microbiota that causes red heart of TQ remain largely unexplored, and it is still unclear how these microbiota influence on the quality of LATB. In this study, two types of TQ, one with a red heart (RH) and another with a non-red heart (NRH), were investigated by high throughput sequencing (HTS) and directional screening of culture-dependent methods. The obtained results revealed the differences in the microbial communities of different TQ and led to the isolation of two species of Monascus. Interestingly, the results of high performance liquid chromatography (HPLC) detection showed that citrinin was not detected, indicating that Monascus isolated from TQ was no safety risk, and the contents of gamma-aminobutyric acid in the fermented grains of RH were higher than that of NRH during the fermentation. Selecting the superior autochthonous Monascus (M1) isolated from the TQ to reinoculate into the TQ-making process, established a stable method for producing the experimental “red heart” Tuqu (ERH), which confirmed that the cause of “red heart” was the growth of Monascus strains. After the lab-scale production test, ERH increased ethyl ester production and reduced higher alcohols production. In addition, Monascus had an inhibitory effect on the growth of Saccharomyces and Aspergillus. This study provides the safe, health-beneficial, and superior fermentation strains and strategies for improving the quality of TQ and LATB. [ABSTRACT FROM AUTHOR]

The pink-red color of traditional sausages (cured meat) is the result of nitrite addition and the formation of nitrosomyoglobin. However, the pleasant color of processed meat products is a side effect of nitrite addition while the main anticipated goal is to suppress the germination of clostridial spores. The fungus Monascus is known as a producer of oligoketide pigments, which are used in Asian countries, especially in China, for coloring foods, including meat products. Although, different biological activities of Monascus pigments have been tested and confirmed in many studies, their effect on germination of bacterial spores has never been investigated. This study is focused on testing the activity of red yeast rice (RYR) extract, containing monascin, rubropunctatin, rubropunctamine complexes and monascuspiloin as the main pigments, on germination of Clostridium and Bacillus spores. It was found that addition of nitrite alone, at the permitted concentration, had no effect on spore germination. However, the combined effects of nitrite with NaCl, tested after addition of pickling salt, was efficient in inhibiting the germination of C. beijerinckii spores but had no effect on B. subtilis spores. In contrast, total suppression of C. beijerinckii spore germination was reached after addition of RYR extract to the medium at a concentration of 2% v/v. For B. subtilis , total inhibition of spore germination was observed only after addition of 4% v/v RYR extract to the medium containing 1.3% w/w NaCl. [ABSTRACT FROM AUTHOR]

Huangshui is a by-product of Chinese liquor and it has a high annual production owing to the popularity of the liquor in China. The aim of this study was to investigate the feasibility of Huangshui esterification by whole-cell enzymes produced from different microbial strains. Esterification of Huangshui was carried out for 16 days via the addition of different preparations produced from Rhizopus chinensis strain 3.1149, Rhizopus chinensis strain 3.1166, Monascus purpureus SICC 3.19 and Rhizopus oryzae SICC 3.623. The results showed that the preparation GP1, produced from M. purpureus, exhibited the highest esterification efficiency compared with the other preparations based on physicochemical analysis in combination with volatile profile analysis. In addition, a characterization of preparation GP1 was performed and the optimal alcohol content and pH for esterification were 10% and pH 3.5, respectively. Under the optimal conditions, the total ester content increased from 4.86 to 7.31 g/L after esterification for 16 days. An estimation of the sensory impact of the volatile compounds after esterification was performed by a calculation of the odour active values (OAVs). Radar diagrams of the OAVs demonstrated the differences in the sensory profiles in Huangshui, before and after esterification. Nearly all of the OAVs of the esters were increased by the esterification reaction and were above the human sensory threshold. Results presented in this manuscript provide a potential strategy for the efficient bio-conversion of Huangshui. Copyright © 2014 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

• A census of the fungal microbiomes of 13 regional Hong Qu varieties was completed. • Fungal community composition and diversity is different in Hong Qu varieties. • 14 biomarker taxa were identified to distinguish regional varieties. • Correlations of fungal abundances and fermentation characteristics were explored. • 10 key fungal genera were found to be responsible for fermentation characteristics. Hong Qu glutinous rice wine (HQ wine) is a traditional alcoholic beverage produced in China by fermenting cooked rice using a fermentation starter prepared with the fungus Monascus purpureus. This starter (Hong Qu , HQ) is made empirically by open spontaneous fermentation that is hard to control and standardize, resulting in inconsistent wine quality. This study investigates representative HQ samples from a large geographic region. It explores fungal microbiome compositions, identifies characteristic differences important for the production of various HQ wine styles, and reveals the key fungi responsible for HQ wine fermentation characteristics. The source of the HQ inoculum was found to be the main factor influencing fungal community composition and diversity, followed by processing technology and geographical distribution. Linear discriminant analysis effect size (LEfSe) uncovered 14 genera as potential biomarkers to distinguish regional varieties of HQ. Significant differences were also found in fermentation characteristics such as liquefying power (LP), saccharifying power (SP), fermenting power (FP), total acid content (TA) and liquor-producing power (LPP). The key fungi responsible for LP (5 genera), SP (3 genera), FP (1 genera), LPP (4 genera), and TA (4 genera) were determined using redundancy correlation analysis. Finally, Spearman's correlation analysis indicated that LPP shows a strong positive correlation with FP and LP, while TA displays a strong negative correlation with FP. The results of this study may be utilized to prepare consistently high quality, next-generation HQ by better controlling fungal community structures, and to design fermentation processes for HQ wines with desirable oenological characteristics. [ABSTRACT FROM AUTHOR]

Xuezhikang (XZK) is an extract derived from red yeast rice that is commonly used to treat cardiovascular conditions as a traditional Chinese medicine, both within China and globally. Genotoxicity, acute toxicity, and a 26-week toxicity study in rat have been reported in our previous publication. The present study was designed to assess the long-term safety of XZK when administered orally to dogs. Dogs were treated with encapsulated XZK at a maximum dose of 2000 mg/kg followed by 1000 mg/kg and 500 mg/kg (n = 6/sex/group) for this 26-week oral toxicity study. Control animals were given an empty capsule. Treated animals were then monitored through measurements of body weight, body temperature, food intake, ophthalmic and electrocardiogram examinations, general clinical observations, mortality rates, and clinical and anatomic pathological findings. Additionally, blood samples were collected and used to conduct hematological and biochemical analysis. Several abnormalities were found in all groups including: fecal abnormalities (including mucoid, poorly formed, or liquid feces). Moreover, reduced CHOL and TRIG values were seen in all XZK groups (p < 0.05), increased WBC and NEUT levels in 500 mg/kg group (males only, p < 0.05), and elevated AST, ALT, and ALP activities in 2000 mg/kg group (p < 0.05). These changes were resolved in the recovery period. The results indicated that XZK may temporarily impact the liver enzyme levels, but were not considered adverse effects. These findings yielded a NOAEL for XZK in dogs of 2000 mg/kg. • In 26-week chronic toxicity, the NOAEL of XZK for dogs is 2000 mg/kg. • 2000 mg/kg XZK, for dogs, is corresponds to approximately 60 g/person/day. • XZK maybe temporary impact the liver enzyme level in this study. [ABSTRACT FROM AUTHOR]

Xuezhikang (XZK), an extract derived from red yeast rice, is commonly employed as a traditional Chinese medicine for treating coronary heart disease, improving endothelial function, decreasing blood lipids and preventing other cardiovascular events both within China and globally. However, there have not been studies of the toxicity associated with XZK. In this publication we hope to summarize and evaluate an acute study, a 26-week chronic toxicity study, and the genetic toxicity potential of XZK. Firstly, Sprague Dawley (SD) rats were treated with XZK at dose of 10 g/kg to observe the acute toxicity. Then, we sought to assess the toxicity of XZK (0, 500, 1000, and 2000 mg/kg) in SD rats for 26 weeks with a 4-week recovery period. Lastly, we assessed the genotoxicity of XZK utilizing an Ames test, chromosomal aberration assay, and mammalian micronucleus test. The results of the acute study, XZK did not induce toxicity up to the maximum doses of 10 g/kg in rats, so an LD 50 could not be determined. In the chronic study, XZK administrated via gavage did not alter weight, food intake, urinalysis parameters, hematological analysis parameters, organ weight, organ to weight ratio, microscopic and macroscopic examination of organs. Also, we found no genotoxicity markers at any dose of XZK tested. The results revealed that the no observed adverse effect level (NOAEL) for XZK, based on the 26-week toxicity study, was 2000 mg/kg. Image 1 • In acute toxicity, XZK, at up to 10 g/kg, was well-tolerated for rats. • In 26-week chronic toxicity, the NOAEL of XZK for rats is 2000 mg/kg. • 2000 mg/kg XZK, for rats, is corresponds to approximately 20 g/person/day. • XZK was not mutagenic or clastogenic. [ABSTRACT FROM AUTHOR]

Gutian Hong Qu glutinous rice wine (GHQW) is a representative alcoholic beverage in China. During its traditional brewing process, multiple strains are involved. However, the roles of these microorganisms, particularly their contributions to aroma formation, are poorly understood. Therefore, in this study, the dynamics of volatile components and microbial succession during the traditional fermentation process of GHQW were monitored, by using HS-SPME-GC/MS and high throughput 16 S rRNA and ITS sequencing techniques. Following a 32-day semi-open solid-state fermentation, massive changes in volatile profile and microbial communities were observed. Based on these, the potential correlations between volatile components and microorganisms during the fermentation were explored by using Pearson correlation analysis. It was revealed that 3 bacterial taxa, including Lactococcus lactis , Burkholderia gladioli and Cronobacter helveticus , and 5 fungal taxa, including Wickerhamomyces anomalus , Saccharomyces cerevisiae , Aspergillus vitricola , Aspergillus penicillioides and Monascus purpureus , showed strong connections with various volatile components. Thus these bacteria and fungi might play crucial roles in volatile components biosynthesis, and thus were preliminary considered as core functional microorganisms for GHQW brewing. The detailed information on the dynamic changes of volatile components and microbial communities throughout GHQW brewing can further expand our understanding of the formation mechanisms of GHQW aroma. • A total of 84 volatile compounds are identified during the fermentation of GHQW. • Both bacterial and fungal communities present three separated fermentation phases. • 3 bacteria and 5 fungi present robust association with various volatile components. • Fungi may have greater contribution than bacteria on volatile component synthesis. [ABSTRACT FROM AUTHOR]

Background: Two kinds of soy sauces were prepared with Aspergillus oryzae koji (SSAO) and mixed koji (SSAOM, A. oryzae mouldstarter:Monascus purpureus mouldstarter = 1:2, w/w) respectively. The effects of mixed koji on the essential indices, oxygen radical absorption capacity, color indices, free amino acids and volatile compounds of soy sauce have been studied, followed by a sensory evaluation between SSAO and SSAOM., Results: The contents of non-salt soluble solid, reducing sugar, total acid, total nitrogen and amino nitrogen in SSAOM increased by 21.50%, 9.88%, 15.35%, 5.98% and 41.43%, respectively, compared with the control SSAO, owing to the higher activities of acid protease and glucoamylase in the mixed koji. Moreover, SSAOM showed higher antioxidant activity, higher levels of free amino acids and much more attractive color. Meanwhile, flavor groups such as esters, aldehydes, pyrazines and sulfur-containing compounds in SSAOM were also improved. The contents of free amino acids and aroma compounds were consistent with the sensory evaluation. According to descriptive sensory analysis, SSAOM showed higher intensity for sweet and umami attributes; in addition, higher flowery, burnt, fruity and caramel-like attributes were perceived in SSAOM, while SSAO showed higher ethanolic and sour attributes., Conclusions: The investigated soy sauce prepared with mixed koji can be considered as an effective method to accelerate the fermentation process and improve the flavor of soy sauce., (© 2014 Society of Chemical Industry.)