Preparation of lactic acid bacteria compound starter cultures based on pasting properties and its improvement of glutinous rice flour and dough

The effects of 5 lactic acid bacteria(LAB)fermentation on the pasting properties of glutinous rice flour were compared,and suitable fermentation strains were selected based on the changes of viscosity,setback value,and breakdown value to prepare LAB compound starter cultures.The results revealed that Latilactobacillus sakei HSD004 and Lacticaseibacillus rhamnosus HSD005 had apparent advantages in increasing the viscosity and reducing the setback and breakdown values of glutinous rice flour.In particular,the compound starter created using the two abovementioned LAB in the ratio of 3:1 had better performance than that using a single LAB in improving the pasting properties and increasing the water and oil absorption capacity of glutinous rice flour.Moreover,the gelatinization enthalpy of the fermented samples increased significantly.For frozen glutinous rice dough stored for 28 days,the viscoelasticity of frozen dough prepared by compound starter was better than that of control dough,and the freezable water content was lower than that of control dough.These results indicate that compound LAB fermentation is a promising technology in the glutinous rice-based food processing industry,which has significance for its application.

Effects of lactic acid bacteria-fermented formula milk supplementation on ileal microbiota,transcriptomic profile,and mucosal immunity in weaned piglets

Background:Lactic acid bacteria(LAB)participating in milk fermentation naturally release and enrich the fermented dairy product with a broad range of bioactive metabolites,which has numerous roles in the intestinal health-promot-ing of the consumer.However,information is lacking regarding the application prospect of LAB fermented milk in the animal industry.This study investigated the effects of lactic acid bacteria-fermented formula milk(LFM)on the growth performance,intestinal immunity,microbiota composition,and transcriptomic responses in weaned piglets.A total of 24 male weaned piglets were randomly divided into the control(CON)and LFM groups.Each group consisted of 6 replicates(cages)with 2 piglets per cage.Each piglet in the LFM group were supplemented with 80 mL LFM three times a day,while the CON group was treated with the same amount of drinking water.Results:LFM significantly increased the average daily gain of piglets over the entire 14 d(P<0.01)and the average daily feed intake from 7 to 14 d(P<0.05).Compared to the CON group,ileal goblet cell count,villus-crypt ratio,sIgA,and lactate concentrations in the LFM group were significantly increased(P<0.05).Transcriptomic analysis of ileal mucosa identified 487 differentially expressed genes(DEGs)between two groups.Especially,DEGs involved in the intestinal immune network for IgA production pathways,such as polymeric immunoglobulin receptor(PIGR),were significantly up-regulated(P<0.01)by LFM supplementation.Moreover,trefoil factor 2(TFF2)in the LFM group,one of the DEGs involved in the secretory function of goblet cells,was also significantly up-regulated(P<0.01).Sequenc-ing of the 16S rRNA gene of microbiota demonstrated that LFM led to selective enrichment of lactate-producing and short-chain fatty acid(SCFA)-producing bacteria in the ileum,such as an increase in the relative abundance of Entero-coccus(P=0.09)and Acetitomaculum(P<0.05).Conclusions:LFM can improve intestinal health and immune tolerance,thus enhancing the growth performance of weaned piglets.The changes in microbiota and metabolites induced by LFM might mediate the regulation of the secretory function of goblet cells.

The effects of fermentation and adsorption using lactic acid bacteria culture broth on the feed quality of rice straw

To improve the nutritional value and the palatability of air-dried rice straw, culture broth of the lactic acid bacteria community SFC-2 was used to examine the effects of two different treatments, fermentation and adsorption. Air-dried and chopped rice straw was treated with either fermentation for 30 d after adding 1.5 L nutrient solution(50 m L inocula L–1, 1.2×1012 CFU m L–1 inocula) kg–1 straw dry matter, or spraying a large amount of culture broth(1.5 L kg–1 straw dry matter, 1.5×1011 CFU m L–1 culture broth) on the straw and allowing it to adsorb for 30 min. The feed quality and aerobic stability of the resulting forage were examined. Both treatments improved the feed quality of rice straw, and adsorption was better than fermentation for preserving nutrients and improving digestibility, as evidenced by higher dry matter(DM) and crude protein(CP) concentrations, lower neutral detergent fiber(NDF), acid detergent fiber(ADF) and NH3-N concentrations, as well as higher lactic acid production and in vitro digestibility of DM(IVDMD). The aerobic stability of the adsorbed straw and the fermented straw was 392 and 480 h, respectively. After being exposed to air, chemical components and microbial community of the fermented straw were more stable than the adsorbed straw.

Effect of Lactic Acid Bacterial Inoculants on Rice Straw Silage

The trail was designed to study on technique aspects of ensiling rice straw(RS)appended amounts of lactobacillus.There were two groups according to silage ways,baled silage(BS)and chopped silage(CS),in which lactobacillus was added at levels of 10,15 and 20 mg.kg-1,respectively and the mixtures were placed into a packed polyethylene bags and stored at room temperature for 45 days.The results showed that lactobacillus had remarkable effect on fermentation characteristics of RS.The quality of the silage was improved with the lactobacillus addition.In the experiment the optimal quality of rice straw silage(RSS)can be obtained when lactobacillus was added with 15 or 20 mg.kg-1 level.The effect of different silage methods was very remarkable to the silage quality of same material.The quality of CS was better than that of long silage,at the same time,BS was feasible on condition of eligible level of lactic acid bacteria.

全株水稻表面优势乳酸菌的筛选与鉴定

本试验旨在对全株水稻表面的优势乳酸菌进行分离、筛选与鉴定,以期挖掘出青贮优良菌种资源。利用平板涂布法对全株水稻上的乳酸菌进行分离,以生长速度和产酸能力进行初筛,以抗氧化能力(H2O2耐受能力、DPPH自由基、羟自由基和超氧阴离子自由基清除率)进行复筛,对筛选出的优势乳酸菌进行生理生化特性分析和分子生物学鉴定。结果表明,从水稻植株表面共分离得到154株乳酸菌,培养48 h后,有16株OD_(600nm)值>2且pH值<4的乳酸菌,其中有9株乳酸菌具有抗氧化能力,综合表现最好的菌株是YMA3,对DPPH自由基、羟自由基、超氧阴离子自由基清除率分别为72.23%、72.46%、86.33%。YMA3表现出较强的高温或酸性环境适应性,鉴定为粪肠球菌。

3种乳酸菌发酵米浆对发糕品质的影响比较研究

目的以清酒乳杆菌清酒亚种、类干酪乳酪杆菌类干酪亚种、发酵黏液乳杆菌为发酵菌种,研究3株不同乳酸菌发酵米浆对米发糕品质的影响。方法米发糕由发酵的大米磨成米浆,再经酵母发酵,加热汽蒸而成。以米浆的密度、黏度、持水率、流变特性为测定指标,测定乳酸菌发酵米对米浆性质的影响;以米发糕的质构、感官、比容为测定指标,测定乳酸菌发酵对米发糕品质的影响。结果乳酸菌发酵原料大米相比其自然发酵和未发酵大米制作的米浆,米浆的密度与酸度最低、米浆的持水性与黏度最高,具有良好的流变学特性;不同乳酸菌菌种由于产酸与酶量不同,对米浆性质影响也不同,3株乳酸菌中发酵黏液乳杆菌发酵黏液乳杆菌制作的米浆密度小、黏度大、pH低、发酵能力强、流变特性中稠度系数大;米浆性质对米发糕的品质有直接影响,乳酸菌发酵相比于其他方法对米浆性质影响大,制得的米发糕品质最好,如比容较大、弹性较大、内部气孔均匀致密;不同乳酸菌发酵米浆性质不同导致米发糕品质也不同,3株乳酸菌中发酵黏液乳杆菌制作的米发糕的比容最大、硬度最大(1409.43gf)、咀嚼性最大(718.81gf)、黏聚性与回复性最优。结论发酵黏液乳杆菌发酵米发糕感官评分最高,类干酪乳酪杆菌类干酪亚种与清酒乳杆菌清酒亚种发酵米糕的性质次之。发酵黏液乳杆菌发酵黏液乳杆菌发酵米制作米浆与米发糕品质较好,为米发糕的制作提供新的菌种选择。

复配乳酸菌黑米发酵乳工艺优化及抗氧化活性研究

利用植物乳杆菌、嗜酸乳杆菌和鼠李糖乳杆菌混菌发酵制备黑米发酵乳,通过响应面试验优化发酵工艺,并测定其抗氧化活性。结果表明:当发酵时间4 h、发酵温度37℃、黑米浆与牛奶的体积比1∶1.7时,黑米发酵乳的感官评分达到86.91±3.24,具有较强的抗氧化活性。

乳酸菌发酵对混合米粉理化特性及年糕品质的影响

以嗜酸乳杆菌(HSP001)、清酒乳杆菌(HSP002)及复配菌株为发酵剂制备发酵混合米粉,分析乳酸菌发酵对混合米粉理化特性及年糕品质的影响。结果表明:乳酸菌发酵能显著提高混合米粉的持水性。糊化特性研究表明,清酒乳杆菌发酵的混合米粉的谷值黏度(TV)最高(1295 cP),衰减值(BDV)最小(394 cP),最终黏度(FV)最大(1295 cP),增强了凝胶产品的稳定性。流变特性研究表明,嗜酸乳杆菌发酵的混合米面团的储能模量(G′)和损耗模量(G″)最高,损耗正切值(tanδ)最小,弹性增强趋势明显。质构特性和蒸煮损失研究表明,以嗜酸乳杆菌发酵的混合米粉制备的年糕,其硬度及咀嚼性最低,凝聚性最好,蒸煮损失最少。感官评定结果显示:复配乳酸菌发酵制备的年糕呈现良好的感官品质。GC-MS分析表明:相较于单一菌株,复配乳酸菌发酵制备的年糕,醛类和酯类化合物的种类及含量有所增加,产品具有特有的发酵香味。研究结果为传统米制发酵食品研究与生产提供借鉴。

乳酸菌发酵大米工艺优化制备米发糕研究

以米发糕感官评分为考核指标,利用响应面法优化乳酸菌发酵大米工艺,并对制作的米发糕与市售米发糕进行对比分析。结果表明:最佳发酵工艺参数为乳酸菌发酵温度26℃、发酵时间23 h、菌液接种量1.4%(以大米质量为基准),在此条件下制作的米发糕感官评分为84.6,口感柔软细腻,有柔和的发酵香气,内部气孔均匀致密,品质优于市售米发糕。

苗族白酸汤中优势乳酸菌及酵母菌的筛选与应用

目的:为了得到适合白酸汤发酵的发酵剂,实现传统白酸汤的规范性生产。方法:采用溶钙圈法结合总酸产量和耐酸耐胆盐实验筛选乳酸菌优良菌株;采用糖苷酶活性实验筛选酵母菌优良菌株;通过生理生化实验、16S rDNA序列和ITS序列进行菌株鉴定。将两株优良发酵菌株复配应用于白酸汤中,对其pH、总酸、总糖、还原糖和感官品质进行分析。结果:从128株乳酸菌中筛选出1株产酸能力较强的菌株G1-3,该菌株在pH3.0与0.3%牛胆盐环境中均生长良好,从20株酵母菌中筛选出1株糖苷酶活性较强的菌株G2-2。经鉴定菌株G1-3为副干酪乳酸杆菌(Lactobacillus paracasei),G2-2为印迪卡有孢圆酵母(Torulaspora indica)。两株菌复配发酵后的籼米白酸汤的总酸含量较自然发酵提高了5倍,总糖与还原糖含量分别降低了61.53%与81.02%;糯米白酸汤中的总酸含量较自然发酵提高了18倍,总糖与还原糖含量分别降低了68.86%与86.99%。两株菌复配发酵后的白酸汤的感官品质也优于自然发酵。结论:G1-3与G2-2的复合发酵剂发酵得到的白酸汤具有较好的品质,有望应用于白酸汤的发酵生产。

酵母发酵米浆制作米发糕工艺

该研究以感官评分为指标,以乳酸菌预先发酵大米为原料,以水、糖、酵母粉的添加量,酵母发酵时间与发酵温度为单因素变量,基于响应面法优化酵母菌发酵米浆制作米发糕的工艺参数。研究表明,最佳制作工艺为乳酸菌预先发酵的湿米500 g、水270 mL、绵白糖49.0 g、酵母粉2.0 g、酵母发酵时间2.0 h、酵母发酵温度35℃,在该配方下制作出的米发糕感官评分为87.13,米发糕的口感绵软、内部气孔均匀致密、色泽纯正、有柔和的发酵香气。

乳酸菌发酵改善脱脂富硒米糠的抗氧化活性

富硒米糠是生产富硒精米过程中的主要副产品,富含硒、膳食纤维及酚类化合物等活性物质,但其高值化利用尚未充分开发。本研究利用4种乳酸菌(嗜酸乳杆菌、嗜热链球菌、植物乳杆菌、保加利亚乳杆菌)对脱脂富硒米糠进行发酵处理,比较了发酵后富硒米糠理化指标、营养特性、微观结构、物化特性及抗氧化活性。结果表明,乳酸菌发酵使脱脂富硒米糠非水溶性膳食纤维/水溶性膳食纤维增加20%~45%。发酵后富硒米糠总酚、总黄酮质量分数分别增加5%~6%、16%~31%,且无机硒转化为SeCys_(2)的效力提高42%~49%。发酵使富硒米糠粒径变小,颗粒表面疏松多孔,水合特性、胆固醇吸附力和抗氧化活性增强。主成分分析综合得分排序为植物乳杆菌>保加利亚乳杆菌>嗜热链球菌>嗜酸乳杆菌,其中植物乳杆菌体外抗氧化活性相对最强,总酸、SeCys_(2)、总酚和总黄酮含量相对最高。本研究为促进富硒米糠的精深开发利用提供了一定的理论依据。

乳酸菌发酵对海红米糠的结构和功能特性的影响

该研究用乳酸菌对海红米糠(sea red rice bran,SRRB)进行发酵处理,并分析比较发酵前后SRRB的微观结构和功能特性的变化。结果表明,发酵海红米糠(fermented sea red rice bran,FSRRB)营养成分得到改善,表面结构变得更加松散,颗粒更小。红外光谱结果显示,发酵前后SRRB主要官能团未发生明显变化,特征吸收峰的整体峰型和位置不变,但发酵后部分吸收峰强度有所减弱,可能与多糖降解有关。其次,发酵后SRRB的持水性和溶解性显著增加。此外,FSRRB的胆固醇吸附能力显著增强,由发酵前的0.03 mg/g(pH_(2).0)和0.10 mg/g(pH 7.0)增加到0.22 mg/g(pH_(2).0)和0.20 mg/g(pH 7.0),均显著高于SRRB。综上所述,SRRB经乳酸菌发酵处理后结构得到改善,功能特性得以增强,采用乳酸菌发酵方式可为提高海红米的综合利用率,促进特色稻全谷物的利用发展提供新思路和理论依据。

添加红曲对乳酸发酵剂发酵性能的影响研究

乳酸发酵是加工新鲜果蔬、制作泡菜的主要方法,发酵剂的性能直接影响最终产品的品质和安全性。该研究通过测定乳酸发酵剂发酵过程中乳酸菌活菌数、发酵酸度、产酸能力、蔗糖和葡萄糖浓度的变化,对腐败菌的抑制作用和亚硝酸盐的降解率等指标进行研究。结果表明,添加红曲米的乳酸发酵剂各方面性能均得到了改善,与对照组相比,添加4%红曲的实验组活菌数为1.245×10^(8)CFU/mL,高于对照组33.7%,TAC为6.70 g/L,高于对照组25.7%,蔗糖含量比对照组低89.4%,对大肠杆菌和金黄色葡萄球菌抑菌圈的直径比对照组大,分别约75%和55.5%,亚硝酸盐降解率高于对照组12.1%,证明红曲对乳酸发酵剂主要性能的提升能起到显著的作用。该研究结果可为改良乳酸发酵剂、研发红曲乳酸发酵剂提供实验基础。

Effects of applying lactic acid bacteria to the fermentation on a mixture of corn steep liquor and air-dried rice straw

This study was to determine the fermentation quality of a mixture of corn steep liquor(CSL)(178 g/kg wet basis) and air-dried rice straw(356 g/kg wet basis) after being treated with inoculants of different types of lactic acid bacteria(LAB). The treatments included the addition of no LAB additive(control),which was deionized water; homo-fermentative LAB alone(^(ho)LAB), which was Lactobacillus plantarum alone), and a mixture of homo-fermentative and hetero-fermentative LAB(^(he+ho)LAB), which were L. plantarum, Lactobacillus casei, and Lactobacillus buchneri. The results showed that the inoculation of the mixture of CSL and air-dried rice straw with ^(he+ho)LAB significantly increased the concentration of acetic acid and lactic acid compared with the control(P < 0.05). The addition of ^(he+ho)LAB effectively inhibited the growth of yeast in the silage. The concentration of total lactic acid bacteria in the ^(he+ho)LAB-treated silage was significant higher than those obtained in other groups(P < 0.05). The duration of the aerobic stability of the silages increased from 56 h to >372 h. The control group was the first to spoil, whereas the silage treated with ^(he+ho)LAB remained stable throughout the 372 h period of monitoring. The results demonstrated that the ^(he+ho)LAB could effectively improve the fermentation quality and aerobic stability of the silage.

乳酸菌浸米技术对黄酒酿造的影响

将乳酸菌浸米技术应用到黄酒生产新工艺中,通过检测米浆水的总酸含量、有机酸含量、生物胺含量以及发酵结束后黄酒的理化指标、感官评价、生物胺含量,分析其在浸米过程中的效果,以及对黄酒酿造过程和成品品质的影响。结果表明,乳酸菌浸米可以加快浸米进程,有效缩短浸米时间;能明显提高米浆水中乳酸菌含量,大幅降低米浆水和黄酒原酒中的生物胺含量,提高生物安全性。乳酸菌浸米技术应用于黄酒大生产中,发酵过程安全可控,工艺简单可行,黄酒各项理化指标都符合GB/T 13662《黄酒》中的要求,酒体协调柔和,具有黄酒的典型风格。

液态深层发酵米醋品质提升方法研究

液态深层发酵米醋有原料和酿造菌种单一、高通风快速发酵的工艺特点,故有风味弱,口感单调、偏酸、刺激的缺点。本研究在米醋发酵末期添加乳酸菌发酵后的麦麸提取液,引入后熟工艺,制得食醋,接入的麦麸提取液量为10%,接菌时残酒量为0.6%(v/v),于25~30℃后熟15 d。采用高效液相色谱法检测有机酸成分,发现乳酸含量明显升高;采用气质联用仪对米醋挥发性风味物质进行检测,发现主体挥发性风味物质含量明显增加。

添加乳酸菌和米糠对水稻秸秆青贮品质的影响

为探讨水稻秸秆饲料化的可行性,以中粳水稻秸秆为青贮原料,研究了添加乳酸菌和米糠对水稻秸秆青贮料品质的影响。将新鲜稻草切碎后加入添加物,设乳酸菌组、米糠组、乳酸菌+米糠组,乳酸菌添加量为1 kg鲜稻草中加入0.02 g 1.6×105CFU/g乳酸菌制剂,米糠添加量为1 kg鲜稻草中加入100 g米糠,同时设对照组(无添加物)。原料装入聚乙烯袋青贮,45 d后开袋检测。结果表明,与对照相比,乳酸菌组稻草青贮料的可溶性碳水化合物含量、干物质回收率、乳酸含量和乳酸/乙酸值分别提高了60.63%、3.82%、134.78%和332.64%,挥发性脂肪酸含量、氨态氮/总氮值分别降低了53.74%、36.68%,且差异均达显著水平(P<0.05);米糠组稻草青贮料的可溶性碳水化合物含量、干物质回收率、乳酸含量和乳酸/乙酸值较对照组分别提高了31.06%、17.08%、157.10%和349.31%,挥发性脂肪酸含量、氨态氮/总氮值分别降低了44.90%、46.68%,且与对照差异均达显著水平(P<0.05)。乳酸菌+米糠组的青贮料发酵品质最佳,除酸性洗涤纤维含量与对照差异不显著(P>0.05)外,其他指标均显著优于对照(P<0.05)。pH与挥发性脂肪酸含量呈较强的正相关性,而与乳酸含量和氨态氮/总氮值呈较强的负相关性。综合各测定指标结果表明,同时添加乳酸菌和米糠能更好地改善稻草青贮料品质。

纯种发酵对鲜湿米粉品质的影响

对比研究2株乳酸菌、2株酵母与自然发酵对鲜湿米粉品质的影响。结果表明,Lactobacillus plantarumCSL23发酵36~48 h时,鲜湿米粉的拉伸力、硬度、弹性、内聚性、咀嚼性、回复性和吸水率在4株菌中最高,蒸煮损失率最低。Lactobacillus fermentum CSL30发酵48 h时,鲜湿米粉的拉伸力、弹性、内聚性、回复性、吸水率和蒸煮损失率仅次于L.plantarum CSL23,而硬度、黏性、咀嚼性最低。自然发酵的鲜湿米粉在发酵60 h时,鲜湿米粉的拉伸力、硬度和咀嚼性较好,质构特点和蒸煮性质居中。Saccharomyces cerevisiae CSY13发酵使鲜湿米粉具有明显的风味特征,但黏性较高、内聚性低。Trichosporon asahii CSY07发酵对鲜湿米粉的拉伸力、质构特点和蒸煮性质的影响均不如自然发酵,但对风味的影响仅次于S.cerevisiae CSY13。总之,乳酸菌有利于鲜湿米粉的食用品质,酵母菌有利于风味;纯种发酵均可以使鲜湿米粉的品质在更短时间内达到最佳状态。

Tween80对稻草水解及同步糖化与发酵产乳酸的影响

在生物转化纤维原料产乳酸的过程中,酶解纤维原料产还原糖是限速步骤。为了获得较高的产物产率,需较高的酶用量,这使大规模酶解废弃纤维原料的成本很高。对吐温80在酶解稻草纤维素产糖,以及耐高温乳酸菌同步糖化发酵稻草产乳酸过程中的作用进行了考察。初步结果表明,吐温80加入可使保持同等程度的水解率所需的酶用量降低,添加0.2 g/g底物的吐温80到酶用量10 FPU/g体系,水解120 h的糖产率为292.2 mg/g,比不加表面活性剂体系的糖产率增加了11%;添加0.7 g/L的吐温80进行同步糖化与发酵72 h,能使乳酸产量提高24.2%。