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植物乳杆菌冻干保护剂的优化及其保护机制 总被引:1,自引:0,他引:1
为优化以菊粉为主要基质的植物乳杆菌冻干保护剂配方,通过部分因素试验设计筛选保护剂成分,利用中心优化组合设计确定最佳保护剂配方,从菌体形态和细胞膜水平研究保护剂对植物乳杆菌的保护机制。试验结果表明,添加菊粉对植物乳杆菌的冻干存活率影响显著,谷氨酸钠和山梨醇能增强对植物乳杆菌的保护效果;优化后的植物乳杆菌冻干保护剂配方:菊粉22.4 g/100 m L,谷氨酸钠12.8 g/100 m L,山梨醇4.7 g/100 m L。在此条件下植物乳杆菌存活率达86.5%。扫描电镜观察结果表明,添加复合冻干保护剂的植物乳杆菌菌体饱满、完整,而未添加保护剂的空白对照有明显的变形、塌缩,细胞间有丝状物粘连。冻干后植物乳杆菌胞内蛋白有不同程度的泄漏,添加含菊粉的保护剂的菌体胞外蛋白量明显低于对照组。结论:以菊粉为主要基质的复合冻干保护剂,可减轻冻干对植物乳杆菌的损伤,其作用机制是通过保护细胞膜实现对菌体的保护。 相似文献
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乳酸链球菌冻干保护剂的筛选和优化 总被引:1,自引:0,他引:1
通过采用9因素2水平Plackett-Burman设计法,对可溶性淀粉、蔗糖、甘油、大豆粉、海藻糖、甘露醇、明胶、甘氨酸和谷氨酸钠9种材料对乳酸链球菌的保护效果进行评价.结果表明:乳酸链球菌的有效冻干保护剂是大豆粉、蔗糖、甘油和甘露醇.通过正交试验设计确定最优冻干保护剂的配方组合和用量,即大豆粉10%、蔗糖10%、甘油3%和甘露醇0.8%(均为质量分数),经过多次实验证明最优保护剂配方组合能使乳酸链球菌的冻干存活率达到77.85%. 相似文献
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以漂白针叶木浆为原料,通过TEMPO氧化法制得纤维素纳米纤维(CNF),再经冷冻干燥制得低密度、高比表面积及高压缩强度的CNF气凝胶。针对CNF气凝胶强度较低并且孔径分布不均的问题,本研究采用在CNF悬浮液中加入不同种类的冻干保护剂(山梨醇、甘露醇及蔗糖)的方法,达到缩小气凝胶孔隙结构,增强气凝胶压缩强度的效果。使用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、比表面和孔径分布分析仪、X射线衍射仪(XRD)、红外光谱仪(FT-IR)和热重分析仪(TG)等对其结构及性能进行表征。结果表明,加入冻干保护剂(山梨醇、甘露醇及蔗糖)后,制得的CNF气凝胶尺寸均一,直径为10~20 nm;气凝胶孔隙分布趋于均匀,压缩强度显著提高。此外,冻干保护剂的加入不会对CNF气凝胶的晶型结构及热稳定性产生影响。 相似文献
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研究了培养基、冻干保护剂、饥饿处理对冻干乳酸菌存活性的交互影响。结果表明,培养液中加入NaCl、干燥介质中添加冻干保护剂蔗糖、冻干前对L.bulgaricus S-1细胞饥饿,这三种处理都可以提高冻干菌体在贮藏期的存活性;然而当培养液中含有NaCl时,保护剂蔗糖以及对细胞饥饿处理并不能进一步提高该培养液中生长的细胞在贮藏期的存活性。 相似文献
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Water activity, oxygen solubility and density of aqueous solutions of sugar and sugar alcohols have been modeled with the statistical associating fluid theory (SAFT). The modeling is accomplished by extending the previously developed method to determine the SAFT parameters for sugar and sugar alcohols. For the aqueous solutions of sorbitol/water, xylitol/water, mannitol/water, xylitol/sorbitol/water and xylitol/mannitol/water, the water activity has been predicted. The solubilities of oxygen in water and in aqueous solutions of glucose/water, fructose/water, sucrose/water, maltose/water and mannitol/water have been modeled. The density predictions for mannitol/sucrose/water, mannitol/sorbitol/water and mannitol/sorbitol/sucrose/water have been carried out. All the modeling results show that, by using the previously developed method to determine the SAFT parameters, the SAFT model has been able to model the water activity, oxygen solubility and density with very good accuracy, and the SAFT model can be taken as a suitable tool for describing sugar and sugar containing solutions. 相似文献
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运用超高效液相色谱-四极杆/静电场轨道阱高分辨质谱,研究了大曲中果糖、葡萄糖、蔗糖、麦芽糖、乳糖和甘露糖醇的分析方法。块状大曲粉碎后过筛,水为提取溶剂振荡提取,乙腈沉淀非目标物,最终用体积分数75%的乙腈水溶液稀释样品,过0.22 μm微孔滤膜后进样分析检测。结果表明,果糖、蔗糖、麦芽糖、乳糖在0.10~25.00 mg/L质量浓度范围内,葡萄糖、甘露糖醇在0.10~50.00 mg/L质量浓度范围内线性关系均良好,相关系数R2>0.99,在添加水平为100.0~5 000.0 mg/kg条件下,样品平均回收率为82.3%~108.4%,相对标准偏差(RSD)为3.4%~9.4%,检出限为0.01~0.07 mg/L。该方法简单、灵敏度高、重现性好、结果准确可靠,适用于大曲中5种糖和甘露糖醇的检测需求。 相似文献
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建立高效液相色谱-蒸发光散射法(High performance liquid chromatography with evaporative light-scattering detection,HPLC-ELSD)同时测定微胶囊中阿拉伯糖、果糖、葡萄糖、蔗糖、麦芽糖、乳糖含量的高效液相色谱方法。样品经乙腈水超声波浸取,采用Waters Amide色谱柱(4.6×250mm3.5μm)分离,以1%氨水和乙腈为流动相,使用蒸发光散射检测器进行检测。结果表明,阿拉伯糖:0.44~7.06mg/mL、果糖:0.30~4.74mg/mL、葡萄糖:0.40~6.45mg/mL、蔗糖:0.32~5.04mg/mL、麦芽糖:0.40~6.47mg/mL及乳糖:0.41~6.61mg/mL范围内线性关系良好;方法检出限为0.02~0.03mg/mL;回收率为95.31%~105.33%,6种糖含量相对标准偏差在2.30%~3.50%之间。该方法前处理简单、灵敏度高和检测速度快,适用于微胶囊中阿拉伯糖、果糖、葡萄糖、蔗糖、麦芽糖、乳糖的定量检测。 相似文献
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Lactose‐sugars systems were produced by spray drying. They were lactose, lactose–glucose (4:1) mixtures, lactose–maltose (4:1) mixtures, lactose–sucrose (4:1) mixtures, lactose–trehalose (4:1) mixtures, and lactose–corn syrup solids (CSS) (4:1) mixtures. The physical characteristics, water sorption behavior, glass transition, and mechanical properties of miscible lactose‐sugars systems were investigated. Lactose–glucose mixtures had larger particle size than other lactose‐sugars systems after spray drying. The presence of glucose or sucrose in lactose‐sugars mixtures decreased the glass transition temperatures of amorphous systems, while the presence of maltose and trehalose had only minor impact on the glass transition temperatures. Moreover, glucose accelerated the crystallization of amorphous system at 0.44 aw, but its presence delayed the loss of sorbed water at higher water activities (≥0.54 aw). Mechanical property study indicated that glucose and sucrose in amorphous system could result in an increase of molecular mobility, while the presence of CSS could decrease the free volume and maintain the stiffness of the miscible systems. 相似文献
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本研究对湖北恩施烟区青枯病菌(Ralstonia solanacearum)的生理小种、生化型和演化型进行了鉴定,为湖北省烟草青枯病抗性品种的选育和利用提供了理论依据。从湖北恩施地区的8个县(市)采集青枯病感病烟株,通过平板稀释分离和特性性引物检测从中分离鉴定到54个具有致病性的烟草青枯菌菌株。采用注茎接种法将供试菌株分别接种青枯菌6个鉴别寄主,确定所有的菌株均属于生理小种1;基于青枯菌对3种双糖和3种己醇利用能力的检测结果,将54个菌株鉴定为生化型Ⅲ;经青枯菌演化型PCR检测,54个菌株均能扩增得到片段大小分别为280 bp和144 bp的两条特异性条带,这说明全部分离菌株均属于青枯菌演化型Ⅰ型。 相似文献
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Storage changes in dark chocolate samples sweetened with five different carbohydrate sweeteners, namely, sucrose β-D-fructose, maltose hydrate, L-sorbose and sorbitol at two added levels of the surfactant lecithin were evaluated by hygroscopicity measurements at different relative humidities (RH) and for mold damage at 100% RH. Sorption isotherms of the samples showed that β-D-fructose and sorbitol are particularly unsuitable in themselves as chocolate sweeteners because of their wide humectant ranges while only L-sorbose compared adequately with sucrose and showed no mold damage after 10 days at 100% RH. The importance of the surfactant lecithin as an additive particularly in chocolate products designed for high humidity conditions e.g. in the tropics, is also discussed. 相似文献
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Preparation of acceptable low sugar jams and replacement of sucrose by other sweeteners in jam were studied. Strawberry jam was sweetened with sucrose, fructose, high fructose syrup (HFS), xylitol, sorbitol, lactose, saccharin, cyclamate, or with combinations of these. It was technologically possible to prepare jams with lower amounts of sucrose than currently used and still attain an acceptable product. In addition, sucrose can be replaced in strawberry jam by other sweeteners or by combinations of sweeteners. The attainment of a suitable texture may be more difficult in xylitol and sorbitol jams than in jams with other sweeteners. The use of maltodextrin as bulking agent in jam is limited by the abnormal appearance and taste it gives to the product. 相似文献
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Glass transition of rainbow trout muscle was measured by differential scanning calorimetry (DSC) as ?13°C. Sucrose and sorbitol (2, 2), sucrose and mannitol (2, 2), sucrose and gum arabic (2, 0.15), sucrose and carrageenan (2, 0.15), sorbitol and mannitol (2, 2), sorbitol and gum arabic (2, 0.15), sorbitol and carrageenan (2, 0.15), mannitol and gum arabic (2, 0.15) and mannitol and carrageenan (2, 0.15) were blended with ground rainbow trout as g/100 g fish and stored for 6 months separately at ?9°C, ?13°C and ?18°C. Total volatile basic nitrogen (TVB-N) and Thiobarbituric acid-reactive substances (TBARS) were determined at 1st, 3rd and 6th months of storage periods. Biopolymers blends, storage temperature and storage period had a significant effect (p < 0.05) on the TVB-N and TBARS values. 相似文献