Production of microbial oils co-fermented by Trichoderma.koningii and Trichosporon cutaneum with Daqu distiller's grains

Daqu distiller's grains were co-fermented as raw materials by Trichoderma.koningii and Trichosporon cutaneum to produce microbial oils,which can provide raw materials for bio-diesel development.The single factor tests were used to investigate the effects of ratio of strains,inoculum size,culture temperature and culture time on the production of microbial oils.The best processing conditions were obtained by orthogonal test through measuring the content of microbial oils in product.The result shows that the microbial oils content of the co-fermented product under the ratio of Trichoderma.koningii to Trichosporon cutaneum of 1:1,the inoculum size of strains of 11% at 28 °C for 6 d is 7.15 g/L.It is shown that the production of microbial oils co-fermented by Trichoderma.koningii and Trichosporon cutaneum with Daqu distiller's grains is possible.The research provides a new idea for the reuse of Daqu distiller's grains and also provides a new way for the development of microbial oils.

Evaluation of Ruminal Dry Matter Disappearance and pH of Dry Corn, High-Moisture Corn, and Rye under in Vitro Conditions

An in vitro experiment was conducted to evaluate the effects of grain type on in vitro dry matter disappearance (IVDMD) and pH using ruminal fluid and a buffer reagent. Five beef cows were used for ruminal fluid collection and ruminal fluid was pooled prior to use. The cows used for ruminal fluid collection were maintained on a forage-based diet (60:40 forage to concentrate) for 28 d prior to ruminal fluid collection. Three grain types were evaluated: 1) dry corn (89% dry matter;DRC), 2) high-moisture corn (72% dry matter;HMC) and 3) rye (89% dry matter;RYE). Data were analyzed as a completely randomized design. A total of twenty-one replications of each grain type were used for statistical analysis (n = 63 tubes total). IVDMD was greater (P ≤ 0.05) by 97.1% and 46.4% for RYE compared to DRC and HMC, respectively. Additionally, IVDMD was greater (P = 0.05) by 34.6% for HMC compared to DRC. Final pH was decreased (P ≤ 0.05) for RYE by 12.3% and 2.8% for RYE compared to DRC and HMC, respectively. Also, final pH was decreased (P = 0.05) by 9.8% for HMC compared to DRC. These data indicate that corn harvest method (dry vs. high-moisture) influences IVDMD and final pH and that rye has a greater disappearance of dry matter and lower final pH than corn under in vitro conditions.

Effects of brewers' spent grain protein hydrolysates on gas production, ruminal fermentation characteristics, microbial protein synthesis and microbial community in an artificial rumen fed a high grain diet

Background: Brewers' spent grain(BSG) typically contains 20% – 29% crude protein(CP) with high concentrations of glutamine, proline and hydrophobic and non-polar amino acid, making it an ideal material for producing valueadded products like bioactive peptides which have antioxidant properties. For this study, protein was extracted from BSG, hydrolyzed with 1% alcalase and flavourzyme, with the generated protein hydrolysates(AlcH and FlaH)showing antioxidant activities. This study evaluated the effects of AlcH and FlaH on gas production, ruminal fermentation characteristics, nutrient disappearance, microbial protein synthesis and microbial community using an artificial rumen system(RUSITEC) fed a high-grain diet.Results: As compared to the control of grain only, supplementation of FlaH decreased(P < 0.01) disappearances of dry matter(DM), organic matter(OM), CP and starch, without affecting fibre disappearances;while AlcH had no effect on nutrient disappearance. Neither AlcH nor FlaH affected gas production or VFA profiles, however they increased(P < 0.01) NH_3-N and decreased(P < 0.01) H_2 production. Supplementation of FlaH decreased(P < 0.01)the percentage of CH_4 in total gas and dissolved-CH_4(dCH_4) in dissolved gas. Addition of monensin reduced(P < 0.01) disappearance of nutrients, improved fermentation efficiency and reduced CH_4 and H_2 emissions.Total microbial nitrogen production was decreased(P < 0.05) but the proportion of feed particle associated(FPA) bacteria was increased with FlaH and monensin supplementation. Numbers of OTUs and Shannon diversity indices of FPA microbial community were unaffected by AlcH and FlaH;whereas both indices were reduced(P < 0.05) by monensin. Taxonomic analysis revealed no effect of AlcH and FlaH on the relative abundance(RA) of bacteria at phylum level, whereas monensin reduced(P < 0.05) the RA of Firmicutes and Bacteroidetes and enhanced Proteobacteria. Supplementation of FlaH enhanced(P < 0.05) the RA of genus Prevotella, reduced Selenomonas, Shuttleworthia, Bifidobacterium and Dialister as compared to control;monensin reduced(P < 0.05) RA of genus Prevotella but enhaced Succinivibrio.Conclusions: The supplementation of FlaH in high-grain diets may potentially protect CP and starch from ruminal degradation, without adversely affecting fibre degradation and VFA profiles. It also showed promising effects on reducing CH_4 production by suppressing H_2 production. Protein enzymatic hydrolysates from BSG using flavourzyme showed potential application to high value-added bio-products.

Study on the Saccharification Process of Citrus Vinegar by Fruit-Grain Mixed Fermentation

This study aimed to enhance acid production rate and yield of citrus vinegar, and improve the quality of liquid fermented with fruit juice. [ Method] The saccharification process of citrus vinegar was investigated preliminarily with fruit-grain mixed fermentation method using liquor starters as saccharif- erous agents. [Result] The results indicated that the optimal glutinous rice saccharification conditions were as follows： fruit-grain ratio 3： 1, Aspergillus niger- Monascus purpureus ratio 3： 1, saccharifieafion temperature 60℃, and saccharification time 2.5 h. Under the optimized saccharification conditions, reducing sugar content in saceharified glutinous rice reached 146.43 mg/ml; after fermentation, alcohol content in fermentation broth was 6%, amino nitrogen content was 0.44 mg/ml, and acid yield was 3.1 g/L. [ Conclusion] Citrus vinegar brewed based on the optimized technological conditions exhibited better sensory and physico-chemical properties than that brewed with pure juice.

Dendritic grain growth simulation in weld pool of nickel base alloy

Dendritic grain growth at the edge of the weld pool is simulated using a stochastic numerical model of cellular automaton algorithm. The grain growth miodel is established based upon the balance of solute in the solid/liquid interface of the dendrite tip. Considering the complicated nucleation condition and competitive growth, the dendrite moiphologies of different nucleation condition are simulated. The simulated results reproduced the dendrite grain evolution process at the edge of the weld pool. It is indicated that the nucleation condition is an important factor influencing the grain morphologies especially the morphologies of secondary and tertiary arms.

Optimization of C/N ratio preparation of protein-rich and multi-enzymes feed thallus through synergic fermentation of mixed distillers'grains

A new procedure of determining optimal C/N (the rate of carbon source to nitrogen source) of mixed distillers' grains for combined bacteria synergic fermentation is established. At the same time an improved method evaluating bacteria growth, called method of dry cell weighing by filtering is developed. For each combination of C and N, their initial and residual contents before and after fermentation respectively are determined. Then followed the calculation of utilization of C and N sources by the compound bacteria. The optimal C/N is finally located from among the utilization of C and N of several combinations and the weight of produced mass of oven dried thallus. The conditions of fermentation are: inoculum size 10%, temperature 30 0℃, rotational speed 170 r/min, shake culture time 48h. The best results obtained from orthogonal experiments are: maximum mass of oven dried thallus is 14 693g in a liter liquid medium, maximum utilization rate of carbon source is 98 13% and maximum utilization rate of nitrogen is 78 14%. Optimal C/N is 5 1.

Protein Quality of Amaranth Grains Cultivated in Ethiopia as Affected by Popping and Fermentation

The effect of popping and fermentation on protein quality of three different varieties of amaranth grains cultivated in Ethiopia was evaluated. Total lysine content of the grains was higher than that of commonly available cereals but close to that of legumes. Methionine and cysteine contents in the grains were also higher than that found in cereal and legume proteins. Percentage of total indispensable amino acids, excluding tryptophan, was 43% - 49%, which was higher than WHO reference pattern (31%). Popping resulted in 36% and 37% reduction in total lysine and cysteine contents, respectively, whereas fermentation reduced cysteine, lysine and methionine contents by 16%, 20% and 20%, respectively. From the free amino acids, histidine was the major indispensable amino acid but threonine was not detected. During popping, all free amino acids, except threonine, were reduced. On the other hand, fermentation significantly increased (p < 0.01) most amino acids except arginine, which was significantly decreased (p < 0.01), and tyrosine and glutamic acid, for which no change was observed. Popping decreased in vitro protein digestibility (IVPD) by 8.3% - 17.1% while fermentation increased IVPD by 4.8% - 7.5%. Substitution of amaranth for wheat and/or maize during complementary food formulation could contribute much to the daily requirements of indispensable amino acids of young children.

饲粮发酵啤酒糟水平对闽东山羊生长性能、消化代谢、血清生化指标及瘤胃发酵的影响

本试验旨在研究饲粮发酵啤酒糟水平对闽东山羊生长性能、消化代谢、血清生化指标及瘤胃发酵的影响,为发酵啤酒糟在舍饲闽东山羊的科学利用提供参考。选择体重[(20.89±1.21)kg]相近的8月龄闽东山羊公羊24只,随机分为4组,每组6个重复,每个重复1只羊。对照组、试验Ⅰ组、试验Ⅱ组和试验Ⅲ组饲粮中发酵啤酒糟水平分别为0、12%、24%和36%,各组饲粮营养水平一致。预试期10 d,正试期7 d。结果表明:1)试验Ⅰ组和试验Ⅱ组的干物质采食量显著高于对照组(P<0.05)。对照组和试验Ⅰ组的总能表观消化率显著高于试验Ⅱ组和试验Ⅲ组(P<0.05)。试验Ⅱ组和试验Ⅲ组的酸性洗涤纤维表观消化率显著高于对照组和试验Ⅰ组(P<0.05)。对照组的进食氮显著低于试验Ⅰ组、试验Ⅱ组和试验Ⅲ组(P<0.05)。2)试验Ⅱ组和试验Ⅲ组的血清总蛋白含量显著高于对照组和试验Ⅰ组(P<0.05)。3)试验Ⅱ组和试验Ⅲ组的瘤胃pH显著高于对照组和试验Ⅰ组(P<0.05),试验Ⅰ组、试验Ⅱ组和试验Ⅲ组的瘤胃丁酸含量显著低于对照组(P<0.05)。4)在门水平上,试验Ⅱ组的瘤胃厚壁菌门(Firmicutes)相对丰度显著高于对照组和试验Ⅲ组(P<0.05),试验Ⅲ组的瘤胃拟杆菌门(Bacteroidetes)相对丰度显著高于试验Ⅰ组和试验Ⅱ组(P<0.05)。在属水平上,试验Ⅲ组的瘤胃普雷沃氏菌属(Prevotella)相对丰度显著高于试验Ⅰ组和试验Ⅱ组(P<0.05),试验Ⅲ组的瘤胃琥珀酸菌属(Succiniclasticum)相对丰度显著高于对照组、试验Ⅰ组和试验Ⅱ组(P<0.05),试验Ⅰ组和试验Ⅱ组的瘤胃肠单胞菌属(Intestinimonas)相对丰度显著高于对照组(P<0.05)。由此可见,饲粮中添加发酵啤酒糟可提高闽东山羊的干物质采食量和ADF表观消化率,在一定程度上提升瘤胃纤维素降解微生物的相对丰度,改善瘤胃发酵环境,且对闽东山羊的生长和机体代谢无负面影响。从本试验结果来看,饲粮发酵啤酒糟水平在12%~24%时饲喂效果最佳。

发酵酒糟在养牛产业中的应用研究进展

酒糟作为酿酒产业的副产物,近年在动物饲料中被广泛应用,其可替代日粮中的部分精料用于畜禽养殖,在一定程度上可缓解畜禽养殖业的饲料短缺问题。酒糟经过微生物发酵后能延长储存时间,而且能提高饲料中粗蛋白质含量及优化氨基酸组成,同时降低粗纤维含量,营养价值较高,提升了酒糟的饲用价值。本文主要对几种发酵酒糟特点、利用方式及发酵酒糟在养牛产业中的应用效果的研究进展进行综述,以期为发酵酒糟饲料化的研发与应用奠定基础。

乳酸菌发酵谷物饮料的工艺优化

试验以玉米、大米、小米为原料,以植物乳杆菌为发酵菌株,通过响应面优化试验确定谷物饮料的最佳发酵工艺为按照5%接种量,在30℃条件下发酵25 h,在此条件下做出的谷物饮料色泽均匀一致,有浓郁的谷物香味,酸甜适口,分层较少,没有苦涩的味道。

醋醅源非酿酒酵母的鉴定及其对葡萄酒品质的影响

为改善传统商业酿酒酵母酿造葡萄酒的风味与口感,以醋醅中分离的菌株JM为研究对象,对其进行形态学观察、分子生物学鉴定和耐受性分析;以菌株JM、商业酿酒酵母(SC)和安琪活性生香干酵母(ADY)单菌及混菌发酵酿造葡萄酒,并对其品质进行分析。结果表明,经鉴定,菌株JM被鉴定为扁平云假丝酵母(Candida humilis),在发酵液中总酯产量为2.64 g/L,其可耐受3.0%柠檬酸、温度35℃、体积分数6%的乙醇及4%NaCl。在不同组别葡萄酒样品中,JM+SC混菌制备的葡萄酒品质最佳,其酒体颜色为紫红色,L*值、a*值、b*值分别为53.93、20.38、4.85;糖度为7°Bx,总酸含量为3.38 g/L,还原糖含量为22.00 g/L,pH为3.58,花色苷含量为205.52 mg/L,酒精度为12.60%vol,总酯含量为1.47 g/L;1,1-二苯基-2-三硝基苯肼(DPPH)、2,2'-联氮-双(3-乙基苯并噻唑啉-6-磺酸)(ABTS)自由基清除率分别为42.21%、32.86%;酒样富含丙酸乙酯和乙酸戊酯,果香浓郁,清爽可口,具备酿造高品质葡萄酒的潜力。

白酒糟中添加花生秧与玉米粉对其混合发酵品质和体外瘤胃降解率的影响

本试验旨在通过研究添加不同比例的花生(Arachis hypogaea)秧和玉米(Zea mays)粉对浓香型白酒糟厌氧发酵品质和体外瘤胃降解率的影响,提高白酒糟的营养价值和延长安全储存期。采用2因素3水平试验设计,花生秧的添加量分别为白酒糟(鲜重)的0、5%、10%;玉米粉的添加量分别为白酒糟(鲜重)的0、2%、4%。厌氧发酵后评定发酵品质和体外瘤胃降解率。结果表明:1)厌氧发酵180 d时,添加花生秧显著提高了白酒糟的pH(P<0.05),对乳酸(LA)、乙酸(AA)含量无显著影响(P>0.05),添加玉米粉显著降低了白酒糟的AA含量(P<0.05),对pH和LA含量无显著影响(P>0.05)。同时添加5%花生秧和4%玉米粉显著降低了NH3-N/TN以及丙酸(PA)含量(P<0.05)。对照组的V-Score评分最低,为87.83,同时添加5%花生秧和4%玉米粉处理组的V-Score评分最高,为97.23。2)未经厌氧发酵时,添加花生秧显著提高了干物质(DM)、中性洗涤纤维(NDF)的体外瘤胃降解率(P<0.05),添加玉米粉对DM、NDF的体外瘤胃降解率无显著影响(P>0.05)。同时添加10%花生秧和4%玉米粉显著提高了粗蛋白(CP)、酸性洗涤纤维(ADF)的体外瘤胃降解率(P<0.05)。厌氧发酵180 d时,添加花生秧和玉米粉均显著提高了DM、ADF的体外瘤胃降解率(P<0.05)。同时添加10%花生秧和4%玉米粉显著提高了CP、NDF的体外瘤胃降解率。综上所述,添加花生秧、玉米粉可改善白酒糟厌氧发酵品质,提高发酵白酒糟的体外瘤胃降解率;同时添加5%花生秧和4%玉米粉改善厌氧发酵品质的效果最好,同时添加10%花生秧和4%玉米粉提高发酵白酒糟体外瘤胃降解率的效果最好。

白酒酿造过程中微生物多样性的研究进展

白酒是中国传统的酒类之一,其酿造过程中微生物的多样性对于酒的品质和风味有着重要的影响。近年来,随着科学技术的不断发展,对于白酒酿造过程中微生物的研究也在不断深入。该文对白酒酿造过程中微生物的多样性研究进展进行了综述,包括微生物多样性的研究方法,窖泥、大曲及糟醅微生物群落的多样性。此外,阐述了微生物群落对白酒风味品质的影响,以及白酒中微生物间的相互作用,为白酒酿造微生物的后续研究提供参考。

基于高通量测序技术分析菌草酒发酵过程中的真菌群落变化

【目的】菌草酒是采用菌草为原料酿造的白酒,了解菌草酒不同发酵时期的真菌群落演变规律和优势真菌群落,为建立菌草酒微生物信息数据库、探究菌草酒的发酵机理、提升菌草酒的品质提供理论基础和科学依据。【方法】采用Illumina MiSeq高通量测序技术对菌草酒酿造过程中不同发酵时期的酒醅样本进行测序分析,揭示菌草酒发酵过程中真菌群落的分布和演替规律。【结果】在菌草酒发酵过程中,真菌群落的分布在不同发酵时期不断调整和平衡,共注释到8个门、22个纲、50个目、110个科、243个属。在门水平上分析,优势真菌门包括子囊菌门(Ascomycota)、担子菌门(Basidiomycota)和接合菌门(Zygomycota),平均相对丰度分别为92.32%、4.88%和1.34%,其中子囊菌门是整个发酵过程中的核心优势菌门。在属水平上分析,优势真菌属包括未分类属、酵母属(Saccharomyces)、曲霉属(Aspergillus)、青霉属(Penicillium)、木耳属(Auricularia)、被孢霉属(Mortierella)和镰刀菌属(Fusarium),平均相对丰度分别为45.53%、35.11%、2.72%、2.06%、1.60%、1.25%和1.00%,其中未分类属和酵母属在发酵过程中发挥重要作用。主成分分析(Principal component analysis,PCA)结果显示,发酵前和发酵后样本真菌群落的遗传距离均较远。【结论】菌草酒酿造过程不同发酵时期的酒醅中真菌群落的组成和多样性存在较大差异,而发酵前和发酵后的群落结构差异最为显著。

糟醅分区在浓香白酒正常排次中的应用研究

以糟醅分区为研究对象,展开了正常排次糟醅分区试验组和常规茬醅对比组对本排次以及三区和大茬作为池底对下排池底产酒的分析研究。通过糟醅分区试验组和茬醅对比组对本排次窖池产酒的产量、理化和感官比对分析发现,一区试验相比于小茬对比组酒体产量提升了7.4%,乙酸乙酯和己酸乙酯分别降低了3.8%和6.6%,乳酸乙酯提升了24.2%;二区试验组相比于二茬对比组酒体产量提升了5.3%,乙酸乙酯提升了13.6%,乳酸乙酯和己酸乙酯分别降低了13.5%和6.9%;三区试验组相比于大茬对比组酒体产量降低了11.8%,乙酸乙酯和乳酸乙酯分别降低了26.4%和32.6%,己酸乙酯提升了89.1%;感官上,三区酒的窖香明显,口感更加醇甜协调,一区、二区及三甑茬醅酒体更偏清香风格。通过三区和大茬作为池底对下排次窖池产酒的产量和质量进行比对分析发现,较之大茬-池底对比组,三区-池底试验组酒体产量略有提升,乙酸乙酯、乳酸乙酯和己酸乙酯均有所提升,分别提升了10.4%、15.1%和19.3%,且乙己比和乳己比均有所降低。研究结果为浓香型白酒正常排次优级酒得率提升提供了理论依据,为下排次池底糟醅质量提升提供了一定的技术参考。

发酵酒糟对西威牛血液、分泌型免疫球蛋白A和肠道黏膜相关菌群的影响

为研究发酵酒糟对西威牛免疫指标、炎症指标以及十二指肠细菌群落的影响,试验将18头西威公牛随机分为3组,对照组饲喂基础饲粮,试验1、2组分别添加15%、30%发酵酒糟,预试期15 d,正试期90 d。结果表明:与对照组相比,试验1组免疫球蛋白G(IgG)、分泌型免疫球蛋白A(SIgA)、Muribaculaceae分别显著提高了18.83%、27.99%、25.77%(P<0.05),试验1组疣微菌科UCG-010极显著降低了10.43%(P<0.01),试验2组白介素2、白介素4、白介素6、CD8、免疫球蛋白A、变形菌门、放线菌门、纤维杆菌门、疣微菌门和Muribaculaceae分别显著提高了22.22%、17.43%、19.31%、11.91%、18.91%、31.64%、41.5%、50%、42.86%和25.41%(P<0.05),试验2组瘤胃菌科显著降低了27.17%(P<0.05),试验2组CD4分子、IgG、SIgA和毛螺菌科分别极显著提高了14.53%、24.89%、38.52%和50%(P<0.01),试验2组疣微菌科UCG-010极显著降低24.51%(P<0.01)。与试验1组相比,试验2组CD4分子、毛螺菌科分别显著提高了6.01%、21.36%(P<0.05),试验2组普雷沃氏菌科显著降低了29.20%(P<0.05),试验2组疣微菌科UCG-010极显著降低了12.75%(P<0.01)。由此可见,饲粮添加30%发酵酒糟可提高西威牛的免疫力、降低炎症反应、改善十二指肠菌群,效果优于添加15%发酵酒糟。

酿酒酵母对浓香型白酒酒醅微生物群落结构及功能的影响

通过分析酿酒酵母对浓香型白酒酒醅微生物组成及挥发性代谢物的影响,探究其对酒醅微生物生态网络、挥发性代谢物以及微生物群落代谢功能的作用。将1株分离自浓香型白酒酒醅的酿酒酵母(Y1)扰动酒醅固态发酵过程,采用高通量测序技术和顶空固相微萃取质谱联用技术分析微生物群落构成和挥发性代谢物组成,利用随机森林学习算法计算能够表征试验组与空白组间差异的生物标志物,基于共现性网络模型分析试验组与空白组的微生物生态网络差异,采用PLS-DA和斯皮尔曼相关性分别分析其挥发性风味物质差异、差异代谢物与生物标志物的相关性,最后通过PICRUST2功能预测以及通路富集分析微生物群落潜在功能的改变。结果表明,5种细菌和15种真菌可以作为表征酿酒酵母扰动酒醅中微生物组成的生物标志物,并且提高了微生物生态网络的复杂性;挥发性代谢物的组成发生了改变,共有18种差异代谢物,部分挥发性代谢物的含量得到提高,绝大多数生物标志物与差异代谢呈显著相关。此外,酿酒酵母的扰动效应导致微生物群落出现180个上调基因,46个下调基因,这些基因大多数与物质的代谢有关。这些结果为酿酒酵母在白酒发酵中的应用及优化酒醅发酵过程提供了试验依据。

一种酿酒用酒醅上甑布料机器人的设计与实现

在白酒酿造中,需要用甑锅对酒醅或粮醅进行蒸馏。上甑前,要对物料逐层平铺,遵循“轻、松、匀、薄、准、平”的原则,否则会影响蒸馏效果。针对上述问题,本文分析与探讨了一种酿酒用酒醅上甑布料机器人,其主要由支撑架等部分构成;其中,支撑架下侧设有移动框架,支撑架上侧设有输送机,支撑架左上侧设置有提升机,提升机升降架的下侧设置有拨料减速电机;同时,拨料减速电机输出轴的下侧固定连接有拨料轴,拨料轴的下侧设置有物料拨平翅;另外,固定安装块包括两部分,将原整体升降装置调整为只有刮平轴升降,其结构轻巧,并方便整体移动。实践表明,一台上甑布料机器人可对应多台甑锅,可以有效降低上甑设备的总成本;同时,升降装置设置为丝杆结构,降低了整体重量,提高了承载和稳定性,可以有效确保刮平翅逐层平铺物料。

大豆秸和稻草对甜玉米秸秆和湿啤酒糟混合青贮的影响

甜玉米(Zea mays var.rugosa)秸秆和湿啤酒糟含水量较高,青贮可有效解决其不易贮藏的问题。通过设置甜玉米秸秆单贮、湿啤酒糟单贮、两者不同比例(3∶1和4∶1)混合青贮以及分别添加大豆(Glycine max)秸和稻(Oryza sativa)草将混合青贮的含水量调节为60%和70%,共12个处理,探究混合比例及含水量对其混合青贮发酵品质及有氧稳定性的影响。结果表明:甜玉米秸秆单贮发酵品质良好,湿啤酒糟单贮发酵品质较差,二者按3∶1混贮后显著提高了乳酸及乙酸含量(P<0.05),4∶1混贮后显著提高了乳酸含量(P<0.05),但4∶1混贮后好氧细菌及酵母数量较3∶1高;与甜玉米秸秆单贮相比,添加大豆秸显著提高了混合青贮料的有氧稳定性(P<0.05),有氧暴露7 d后的pH值仍接近4.2,添加大豆秸将含水量调节为60%显著降低了NH3-N含量(P<0.05);添加稻草的所有处理均显著降低了NH3-N含量(P<0.05)。综上,甜玉米秸秆与湿啤酒糟按3︰1的比例混合,并添加大豆秸将含水量调节为60%,其发酵品质好,有氧暴露7 d有氧稳定性也较好。

酱酒1、2轮次窖池不同醅层微生态结构与酸性化合物组成解析及其相关性预测

以酱香白酒酿造过程中1、2轮次上、中、底层窖池酒醅为研究对象,采用高通量测序技术偶联超高效液相色谱等方法解析酒醅中微生物群系结构、酸类化合物结构及其酸类化合物分布与微生物群系相关性,进一步揭示其内在机制。结果表明,2轮次酒醅总酸含量大于1轮次;7种酸类化合物在窖池不同时空径向的分布规律不同;1、2轮次酒醅中乳酸和乙酸含量占比较大。1、2轮次绝对优势细菌属为Limosilactobacillus,优势真菌属为Saccharomyces和Candida,且随发酵时间延长,微生物群系结构差异显著。总酸和酸类化合物含量与Limosilactobacillus、Schizosaccharomyces、Zygosaccharomyces、Candida和Kazachstania相对丰度呈正相关,与Lactobacillus、Saccharomyces、Paecilomyces和Torulaspora相对丰度呈负相关。本研究揭示了酱香白酒1、2轮次窖池酒醅不同时空径向的酸度及酸类化合物与微生物群落间的相关性,可为进一步阐明酱香白酒窖池发酵机理提供理论参考。