植物乳杆菌发酵对豆粕蛋白结构的影响

利用植物乳杆菌发酵降解低温豆粕乳,研究其中大豆蛋白结构的变化。随发酵时间的延长,样品水解度和体外消化率均呈升高趋势,可溶性蛋白粒径分布向低粒径方向移动,说明脱脂豆粕中大豆蛋白经发酵后有一定程度的降解。同时,发酵处理后提取的大豆蛋白与原始大豆蛋白和发酵0 h时提取的大豆蛋白相比,蛋白分子进一步展开,β-折叠含量升高,α-螺旋含量降低,荧光光谱中最大吸收波长发生红移,暴露巯基含量升高。另外,扫描电子显微镜观察结果表明大豆蛋白经发酵后表面不再光滑,出现腐蚀性孔洞。     

植物乳杆菌58发酵豆乳产大豆异黄酮苷元条件的优化

本研究通过测定植物乳杆菌58在不同碳源中的生长和产β-葡萄糖苷酶情况,筛选菌株的最适碳源,并确定接种至豆乳的最佳时间.在接种量、糖含量、发酵时间和发酵温度等单因素实验基础上,根据Box-Behnken中心组合原理进行响应面实验设计,以大豆异黄酮苷元含量为指标,进一步优化菌株58发酵豆乳产大豆异黄酮苷元条件.结果显示,植...     

Improving Functional Properties of Soy Protein Hydrolysate by Conjugation with Curdlan

ABSTRACT:  Soy protein hydrolysate was conjugated with curdlan through the naturally occurring Maillard reaction to extend its application in food processing. The gel-forming and emulsifying properties of soy protein hydrolysates were significantly improved ( P < 0.05) by conjugation with curdlan. The soy protein hydrolysate–curdlan conjugate (SPHCC)–soy protein isolate (SPI) mixed gel had a much thicker network than the soy protein hydrolysate and SPI mixed gel judged from scanning electron microscopic images. The improvement of gelling properties of soy protein hydrolysate by curdlan-conjugate was attributed to both the decrease in the repulsive forces among soy protein hydrolysates and the increase in the solubility. The covalent binding of soy protein hydrolysates and curdlan also showed a profound effect on the antioxidative activity of the soy protein hydrolysates. The higher antioxidative activity of SPHCC was related to the peptide reductants produced from the Maillard reaction and the higher emulsifying property of SPHCC. The conjugates of soy protein hydrolysate and curdlan can be used as a functional food additive having excellent gel-forming, emulsifying properties and antioxidative activity.     

红曲霉对白霉干酪理化及流变特性的影响

对自分离筛选红曲霉在软质白霉干酪中的应用进行研究,采用色差仪、质构仪、流变仪、高效液相色谱等对软质白霉干酪及添加红曲霉的白霉干酪的成分、质构及流变等特性进行测定,并分析添加红曲霉对干酪成熟的影响。结果表明：额外添加红曲霉的白霉干酪颜色发生改变,产生红曲色素,a*值为7.81～19.05。相对于白霉干酪,红曲霉-白霉干酪的蛋白和膳食纤维都有所增加,脂肪并无明显增加。此外,通过流变和质构的分析发现,添加红曲霉后,软质白霉干酪更富有弹性,弹性为90.35～92.15,储能模量G′更高,tanδ值变小。通过测定干酪的功能及有害成分,在红曲霉-白霉干酪中检测到0.05～2.21?mg/kg洛伐他汀和0.54～0.70?mg/kg?γ-氨基丁酸,伴有少量橘青霉素产生,其含量低于国际限量。本研究为红曲霉在乳制品中的应用提供理论支持。     

植物乳杆菌LP21绿色合成纳米硒及对溶藻弧菌的抑菌活性

采用益生菌植物乳杆菌LP21合成纳米硒,为抑制水产养殖中溶藻弧菌感染提供一种新的方法.通过植物乳杆菌LP21绿色合成纳米硒,对所得纳米硒进行透射电镜形貌及能谱分析,粒径仪测定粒径,红外光谱分析纳米硒表面生物分子的分布,并研究纳米硒对溶藻弧菌的抑菌活性.结果 表明,植物乳杆菌LP21还原的纳米硒呈球形,分散性良好;纯化的...     

Antioxidant and free radical-scavenging activities of chickpea protein hydrolysate (CPH)

Chickpea protein hydrolysate (CPH) was fractionated by gel filtration on Sephadex G-25. The antioxidant and free radical-scavenging activities of four CPH fractions (Fra.I, Fra.II, Fra.III, and Fra.IV) were measured using reducing power, inhibition of linoleic acid autoxidation, and 1,1-diphenyl-2- pycrylhydrazyl (DPPH)/superoxide/hydroxyl radical-scavenging assay. The antioxidant activity of Fra.IV (81.13%) was closer to that of α-tocopherol (83.66%) but lower than that of BHT (99.71%) in the linoleic acid oxidation system. Amino acid analyses showed that Fra.IV with the strongest antioxidant activity also had the highest total hydrophobic amino acids content (38.94% THAA) and hydrophobicity (125.62 kcal/mol amino acid residue) compared with the other three fractions. The molecular weight distribution of Fra.IV was found to vary from 200 to 3000 Da.     

植物乳杆菌发酵对燕麦蛋白溶解度和营养特性的影响

利用植物乳杆菌(Lactobacillus plantarum)发酵燕麦酸面团,测定发酵过程中面团酸度和菌落总数的变化以显示菌体在体系中的生长情况,并着重研究乳酸菌发酵对燕麦蛋白的溶解度和体外消化率、氨基酸组成和营养指标的影响。结果表明：植物乳杆菌在燕麦基质中生长良好,具有较强的产酸能力;植物乳杆菌发酵可以显著(P＜0.05)提高燕麦蛋白的溶解度,发酵24h和48h的样品与未发酵样品相比,分别提高了19.50%和54.06%。采用胃蛋白酶和胰蛋白酶两步法分析发酵过程中燕麦蛋白体外消化率的变化,发现植物乳杆菌发酵可以显著(P＜0.05)提高燕麦蛋白的体外消化率。植物乳杆菌发酵对燕麦蛋白的总氨基酸含量及组成无显著影响,但其氨基酸评分(AAS)由原来的71.53提高到76.60,蛋白质功效比值(PER)也有所增加。     

植物乳杆菌发酵紫薯粉对酸面团面包的抗氧化特性及品质影响

采用紫薯粉和植物乳杆菌发酵紫薯粉制作富含花青素的面包,通过对比研究乳酸菌发酵紫薯粉对面包品质的影响;并探讨乳酸菌发酵紫薯粉对面包中花青素含量、总酚含量以及DPPH自由基清除率的影响。结果表明：相比紫薯粉面包,乳酸菌发酵紫薯粉使得面包pH值降低,总酸度(TTA)增加,面包比容有所减小,面包色度C*值增加而色相H*值减小,面包色泽由原来的浅紫色变为浅红色。感官评定的结果显示,采用紫薯粉或乳酸菌发酵紫薯粉制作的面包都为消费者所喜爱。同时,与紫薯粉面包相比,乳酸菌发酵紫薯粉面包的总酚含量和DPPH自由基清除率分别增加了90.8%和6.1%,增强了面包的抗氧化性。     

植物乳杆菌胞外多糖的分离纯化及其乳化特性

在脱脂乳中分别培养植物乳杆菌菌株YW11和菌株SKT109,经三氯乙酸除蛋白、离心、乙醇沉淀、透析、冷冻干燥得到胞外多糖粗品,再经DEAE-Sepharose Fast Flow离子交换柱和Sepharose CL-6B凝胶柱纯化,得到两种胞外多糖纯品。利用气相色谱法分析此两种多糖的单糖组成,并采用KBr压片法观察红外光谱,利用动态光散射方法测定多糖的流体力学半径（Rh）。结果显示：YW11胞外多糖的单糖组成为葡萄糖、半乳糖,其物质的量比为3.45∶1,流体力学半径为69.20 nm;SKT109胞外多糖的单糖组成为葡萄糖、半乳糖,其物质的量比为1.43∶1,流体力学半径为41.74 nm;YW11胞外多糖的乳化能力强于SKT109胞外多糖,但前者的乳化稳定性略低;两种胞外多糖分别与其他乳化剂之间具有一定的协同作用,乳化颗粒的半径主要集中在1～2 μm之间。本研究获得的植物乳杆菌胞外多糖在食品加工中具有潜在的应用前景。     

高压处理大豆分离蛋白水解物对羊肉糜凝胶特性及贮藏期氧化稳定性的影响

为研究添加不同高压处理(0.1、100、200、300 MPa)的大豆分离蛋白水解物(soy protein isolate hydrolysate, SPIH)对羊肉糜凝胶特性及贮藏期间氧化稳定性的影响,以未添加水解物的羊肉糜为对照组,测定了羊肉糜的质构、流变特性和微观结构,同时检测了在4℃贮藏8 d的过程中,羊肉糜的色差、酸价、硫代巴比妥酸值、羰基及总巯基含量。结果表明：与对照组相比,添加不同高压处理的SPIH的羊肉糜硬度、弹性及回复性显著提高(P<0.05);升温过程中,添加不同高压处理的SPIH的羊肉糜弹性模量G′均先下降后上升,且在整个升温过程中,SPIH处理压力为200 MPa时,羊肉糜的G′值始终最高;同一频率振荡下,添加200 MPa处理的SPIH的羊肉糜G′值也最高;扫描电镜结果显示,与对照组相比,添加水解物的羊肉糜结构更加致密均匀;随着贮藏时间的延长,添加不同压力下原料肉质量2.0%的SPIH能够抑制羊肉糜的b~*值(黄度)、酸价、硫代巴比妥酸值和羰基含量的上升以及L~*值(亮度)、a~*值(红度)和总巯基含量的下降,且200 MPa处理的SPIH抑制脂肪、蛋...     

低聚果糖对植物乳杆菌A33发酵酸角汁的影响

使用植物乳杆菌A33对酸角汁进行发酵,研究添加低聚果糖(fructooligosaccharides,FOS)对其发酵过程和贮藏期品质的影响.发酵过程中,添加FOS显著提高了植物乳杆菌A33的产酸能力,其中乳酸和乙酸的最大产量为3.12 g/L和0.34 g/L,分别为空白组的2.5倍和9倍;同时,添加FOS显著提高了...     

Evaluation of Antimicrobial,Antioxidant Activities,and Nutritional Values of Fermented Foxtail Millet Extracts by Lactobacillus paracasei Fn032

Solid-state bioprocessing of foxtail millet by Lactobacillus paracasei Fn032 is a biotechnological strategy to produce fermented foxtail millet meal with more beneficial components. The objective of this study was to evaluate the antioxidant, antimicrobial properties and nutritional values of water extracts from fermented foxtail millet flour and its bran with and without protease. Fermented foxtail millet flour with added protease extract showed higher scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals as well as reducing power than fermented foxtail millet flour and fermented foxtail millet bran extracts. Both extracts, fermented foxtail millet flour and fermented foxtail millet flour with protease, showed significant (P < 0.05) effectiveness inhibition abilities on microbial growth when compared with fermented foxtail millet bran extracts. Amino acid profile revealed that fermented foxtail millet flour with protease, with relatively strongest antioxidant, antimicrobial activity, also had the highest total hydrophobic amino acids content (51.39%) and hydrophobic index (8.47 Kj/mol amino acid residue). Moreover, fermented foxtail millet flour with protease revealed the highest protein content, predicted protein efficiency ratio, and protein digestibility. Molecular weight of the whole extracts varied from 180–5000 Da. Based on the results obtained, fermented foxtail millet flour extracts were relatively effective in the antioxidant, antimicrobial properties assayed and might be potential biological values for application in food products.     

Fermentation of Allium chinense Bulbs With Lactobacillus plantarum ZDY 2013 Shows Enhanced Biofunctionalities,and Nutritional and Chemical Properties

In this study, fermentation of Allium chinense bulbs was carried out with Lactobacillus plantarum ZDY 2013. A decrease in pH from 6.8 to 3.5 and a stable lactic acid bacteria population were observed during 7‐d fermentation. The total phenolic content increased by 2.7‐fold in the aqueous and ethanol extracts of A. chinense bulbs after fermentation. Antioxidant capacity including 2,2‐diphenyl‐1‐picrylhydrazyl radical‐scavenging effect and reducing power of both extracts was significantly (P < 0.05) improved after fermentation. Antagonistic test against 6 pathogens showed that fermentation significantly (P < 0.05) enhanced the antimicrobial activity in both extracts of fermented bulbs, especially in the ethanol extracts of fermented bulbs against L. monocytogenes. Analysis of the free amino acid (FAA) profile by ion‐exchange chromatography revealed that fermentation significantly (P < 0.05) increased total FAA content. In addition, among 27 kinds of volatile components analyzed by headspace–solid phase microextraction–gas chromatography–tandem mass spectrometry, sulfur‐containing compounds accounted for 65.23%, but decreased to 43.65% after fermentation. Our results suggested that fermentation of A. chinense bulbs with L. plantarum could improve their biofunctionalities, and nutritional and chemical properties.     

Physicochemical Properties,Fatty Acid Profiles,and Sensory Characteristics of Fermented Beef Sausage by Probiotics Lactobacillus plantarum IIA‐2C12 or Lactobacillus acidophilus IIA‐2B4

Probiotics may be used to enhance the functionality and nutritional values of fermented sausages. This study aims to evaluate the physicochemical and sensory properties of beef sausages fermented by lactic acid bacteria of Lactobacillus plantarum IIA‐2C12 and L. acidophilus IIA‐2B4. These strains were isolated from beef cattle and have shown to display probiotic features. While the nutrient contents were not affected by the probiotics, the pH, texture, and color varied among the sausages. Further analysis on fatty acids showed different profiles of saturated (C14:0, C17:0, and C20:0) and unsaturated (C14:1, C18:1n9c, C18:2n6c, and C22:6n3) fatty acids in sausages with probiotics. Gas chromatography–mass spectrometry further revealed some flavor development compounds including acid, alcohols, aldehydes, aromatic, ketones, sulfur, hydrocarbons and terpenes, varied among the sausages. Hedonic test showed no difference in the preference toward aroma, texture, and color for untrained panelists.