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.

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.

基于PacBio测序解析浓香型白酒酒醅发酵过程中细菌群落及其代谢特性变化

利用16S r RNA基因全长测序技术PacBio解析浓香型白酒酒醅发酵过程中细菌群落结构及其代谢特性变化,并对细菌菌群与挥发性风味物质间的相关性进行分析。结果表明,根据细菌群落多样性的变化,浓香型白酒酿造过程可分为变化期(0~14 d)和稳定期(14~80 d)。在种水平上注释到12种优势细菌(相对丰度≥1.00%),其中,金山醋酸乳杆菌(Acetilactobacillus jinshanensis)从酿造14 d开始相对丰度>90%。白酒酿造过程中的微生物与挥发性风味物质之间具有一定的相关性,其中,与未命名的罗尔斯通氏菌(Ralstonia sp.)、丝状菌(Thiothrix eikelboomii)相关的物质数量较多,2,4-二叔丁基苯酚和戊酸乙酯几乎与所有优势细菌种存在显著相关性(P<0.05)。功能预测结果表明,与白酒酿造相关的代谢通路中甘氨酸的生物合成和代谢、脂质代谢、核苷酸代谢的相对丰度在发酵过程中提高,但氨基酸代谢、其他次生代谢产物生物合成、辅因子和维生素代谢的相对丰度呈下降趋势。

酱香型白酒面糟入窖方式的研究

酱香型白酒三大典型体中,酱香主要来源于面糟。为了提高酱香白酒的入库合格率,本研究对大综糟醅和面糟分批入窖池的方法进行研究,结果表明面糟入窖的方式影响其出酒质量。本研究提高了出酒质量,增加了企业营收,为提升酱香白酒的入库合格率提供了新的思路,对酱香白酒的长远发展具有重要意义。

酱香白酒堆积工艺糟醅置换技术研究

为探索新老车间糖化堆置换前后糟醅质量和原酒理化的差异,采取糖化堆糟醅置换接种方法,将老车间糖化堆糟醅中驯化成熟的菌种移植至新建车间,为持续驯化新建酿酒车间酿酒微生态环境,加快品质提升做铺垫,逐步提升新产区原酒质量。综合对窖池内微生物分析、风味分析、置换车间原酒尝评,结果表明,微生物含量较常规生产间有提升,新车间通过置换老车间糖化堆糟醅,提高了微生物富集量。本研究可为缩小新老车间质量差异及提升整体原酒品质提供基础数据和探索方向。

“Dietary fibre”: moving beyond the “soluble/insoluble” classification for monogastric nutrition, with an emphasis on humans and pigs

This review describes dietary fibres originating from a range of foods,particularly in relation to their plant cell walls.It explores the categorization of dietary fibres into "soluble" or "insoluble".It also emphasizes dietary fibre fermentability,in terms of describing how the gastro-intestinal tract(GIT) microbiota respond to a selection of fibres from these categories.Food is categorized into cereals,legumes,fruits and vegetables.Mention is also made of example whole foods and why differences in physico-chemical characteristics between "purified" and "non-purified"food components are important in terms of health.Lastly,recommendations are made as to how dietary fibre could be classified differently,in relation to its functionality in terms of fermentability,rather than only its solubility.

Production of value-added peptides from agro-industrial residues by solid-state fermentation with a new thermophilic protease-producing strain

This work aimed to explore an effective way for converting agro-industrial residues into value-added products.A thermophilic protease-producing strain was isolated from soybean meal(SBM)and identified as Bacillus licheniformis by 16S rDNA sequencing.After incubating Bacillus licheniformis CPB2 in casein medium for 24 h,the protease activity,peptide yield,and protein conversion rate of the culture could reach 8.87±0.33 U/mL,68.58%,and 82.27%,respectively.Brewer’s spent grain(BSG)and SBM were used as co-substrates to produce value-added peptides through thermophilic solid-state fermentation(TSSF)with Bacillus licheniformis CPB2.The peptide content of the co-substrates increased from 25.71 mg/g to 112.72 mg/g under the optimal TSSF conditions.The fermented products showed an increased crude protein and free amino acids contents and a decreased crude fat and ash contents as well as trypsin inhibitor activity compared with the unfermented co-substrates.TSSF could degrade macromolecular proteins into peptides,unfold the protein aggregates,and reduce the particle size.Industrial relevance:This work proposed an effective way for the rational and efficient utilization of wet and dry agro-industrial residues to produce value-added products,which showed a broad potential for reducing production costs,saving water resources and energy,and preserving the ecological environment.

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。

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。

苹果幼果-红薯复合果粮醋发酵工艺优化及品质分析

文章以苹果幼果与红薯为原料,采用单因素试验与响应面试验确定苹果幼果-红薯复合果粮醋醋酸发酵的最佳工艺;在此基础上,比较分析发酵前(苹果幼果-红薯复合果粮汁)、发酵后(苹果幼果-红薯复合果粮醋)以及市售苹果醋的抗氧化能力;采用顶空固相微萃取-气相色谱-质谱联用法(HS-SPME-GC-MS)检测发酵前(苹果幼果-红薯复合果粮汁)、发酵后(苹果幼果-红薯复合果粮醋)以及市售苹果醋的挥发性风味物质。结果表明,醋酸发酵的最佳工艺为醋酸菌接种量10%、初始酒精度7%、发酵温度31℃。与苹果幼果-红薯复合果粮汁、市售苹果醋相比,苹果幼果-红薯复合果粮醋具有较强的抗氧化能力,挥发性风味物质更丰富,酸类、酯类物质的种类和含量显著更高。该研究可为苹果幼果-红薯复合果粮醋的开发提供数据支撑。

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。

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。

一种酿酒用粮醅双层堆积糖化床系统的设计与实现

在传统白酒酿造工艺中,粮醅的堆积糖化工序通常在堆积糖化房或糖化箱内进行,堆积的温度、通风等条件不易控制,易造成粮醅的污染,产酸菌污染较多,粮醅生酸大,影响淀粉的出酒率等。针对上述问题,本文对粮醅堆积糖化床系统的工作原理、结构特点及其应用效果进行了分析与探讨,在此基础上,堆积糖化床系统设计有支架、堆积链板床链板、电机、风机、加热盘管等部分,通过设备运行和生产试验,验证了该堆积糖化床系统可以满足设计要求,并符合生产工艺条件;同时,该粮醅堆积糖化床系统的自动化程度较高,提高了酿酒用粮醅堆积糖化工序的机械化程度,降低了粮醅糖化工序的劳动强度。

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。

中国粮谷酿酒技艺或发端于凤翔流考证

中国酿酒技艺及其传承,整体呈现一体多元的特征,即以酒曲作用于粮谷、自然发酵生香为主体,各地不同生态环境下,形成了各自的酿造风格。从西周到唐代持续向全国各地延展,并根据各地的酿酒生态环境,融汇当地已有的酿酒技艺传统而形成基本要素。

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。

面向厌氧发酵的酒糟-废水混合流动特性模拟研究

酒糟厌氧发酵是当前处理酒糟的有效手段,而基于水力碎浆机的酒糟分离技术在保证稻壳和发酵有机质分离的基础上,具有简化设备并降低能耗的优势。采用ANSYS Fluent软件对水力碎浆机内部的酒糟-废水两相流动进行CFD模拟,从速度场、压力场、组分场及流线等方面详细研究了稻壳、有机质和废水的混合流动规律,并进行了稳态和瞬态的流场研究。模拟结果表明,水力碎浆机内转子顶部弯叶内侧的浆料可达到最大速度48.06 m/s,并且沿径向逐渐向外衰减至接近于0;由于转子的高速旋转,其前后分别形成了高压区和低压区,最大工作压力为3.06×10^(5)Pa;浆液整体呈现离心运动,压力由中心向壁面递增,中心处转子周边由于流动形成极大负压,带动中心浆料向下运动,而壁面处压力最大,达0.125 MPa;稳态计算下,水力碎浆机能实现良好混合,混合后浆料固相体积分数为5.72%~5.81%;转子下方的狭缝区域为盲区,此处固定相体积分数达最大值5.81%,因此,可适当提高转子的高度以改进水力碎浆机的性能;瞬态计算下,8 min碎浆过程即可达到所需的混合效果。另外,总结了酒糟-废水混合流动规律,即来自顶部中心的酒糟主要是在重力作用下开始下降,随后在靠近水力碎浆机的区域被转子旋转带入左侧或右侧的漩涡区,从而与浆液良好地混合;而来自顶部侧边的酒糟在重力作用下降时,更快地参与了左右两侧的大漩涡运动。研究结果对于优化酒糟-废水制浆运行参数具有重要意义。