尿嘧啶对植物乳植杆菌LIP-1冻干存活率的影响及其作用机制

为了研究在培养基中添加微量生长因子对菌株冷冻干燥存活率的影响,该研究以植物乳植杆菌LIP-1（Lactiplantibacillus plantarum LIP-1）为研究对象,探究培养基中添加尿嘧啶对菌株冷冻干燥存活率的影响及其作用机制。结果表明与未添加尿嘧啶的空白对照组相比,在培养基中添加0.05 g/L尿嘧啶能够显著提高植物乳植杆菌LIP-1的活菌数与冻干存活率（P＜0.05）。对其作用机制进行探究,发现尿嘧啶的加入能够促使菌株合成更多的尿苷二磷酸（P＜0.05）,从而使肽聚糖含量显著增加（P＜0.05）,进而提高细胞壁的稳定性;同时尿嘧啶的加入抑制了乳清酸向尿苷二磷酸的转化,使胞内的乳清酸含量显著升高（P＜0.05）,菌株利用乳清酸的抗氧化能力减轻了活性氧对细胞膜不饱和脂肪酸的氧化程度,进而减少了细胞膜的损伤程度。结果表明植物乳植杆菌LIP-1通过代谢尿嘧啶减轻了细胞壁与细胞膜受到的冻干损伤,提高了菌株的冻干存活率。研究结果为提高菌株冷冻干燥存活率提供了新的方法和思路。     

高活性益生菌酵素粉的制备及工艺优化

为了提高酵素粉中益生菌的存活率以及产品的活性,该研究以植物乳杆菌Lactobacillus plantarum 1-33(Lp 1-33)为发酵菌株,高密度培养后对发酵上清液进行喷雾干燥;通过内源乳化法对菌体进行微胶囊包埋,再对微胶囊进行真空冷冻干燥,最后2部分产物经混匀造粒制得益生菌酵素粉;以包埋率、胃肠道存活率、释放率等为指标,考察多重保护技术对其活性的保护效果。结果表明:采用内源乳化法,乙二胺四乙酸钙为钙载体,质量分数1.5%海藻酸钠为壁材,质量分数0.3%壳聚糖-三聚磷酸钠为涂层材料效果最佳;此条件下制备的微胶囊包埋率≥80%,经模拟胃液处理2 h后其菌体存活率≥50%,模拟肠液处理2 h后释放率≥90%;最佳冷冻保护剂配方为质量分数10%脱脂奶粉、质量分数8%乳糖、质量分数1%抗坏血酸钠、质量分数1%谷氨酸钠,酵素粉与保护剂比例1:10;制备的酵素粉30℃保存3个月,活菌数仍≥9.5lg(CFU/g);与发酵前果汁相比,其清除自由基能力提高了近20%。通过上述多重活性保护技术,提高了菌体的存活率和抗逆境能力,获得高密度、高活性的益生菌酵素粉,为后续产业化的生产提供技术支撑。     

二苯醚类除草剂降解菌Bacillus sp. Za微生物制剂的研发与初步应用

以二苯醚类除草剂高效降解菌株Bacillus sp. Za为材料制备微生物制剂，优化液体制剂保护剂的物质配比，筛选固体制剂的最适材料，对固体制剂进行初步应用并评价其降解效果。研究结果表明：（1）液体制剂保护剂（0.20%柠檬酸钠、0.20%羧甲基纤维素、0.30% KCl）可使活菌数提高35.71%，保存30 d的液体制剂对50 mg/L乳氟禾草灵的降解率为83.50%。（2）筛选得到猪粪有机肥作为固体制剂的最适材料，保存60 d时固体制剂活菌数为8.26×108 cfu/g，对土壤中10 mg/kg乳氟禾草灵的降解率为85.52%。（3）添加固体制剂可有效缓解乳氟禾草灵残留对玉米所产生的药害。     

除草剂苄嘧磺隆降解菌Hansschlegelia zhihuaiae S113菌剂的研发

磺酰脲类除草剂苄嘧磺隆残留期较长，造成农田土壤的残留污染问题。以苄嘧磺隆高效降解菌株Hansschlegelia zhihuaiae S113为材料制备降解菌剂，优化液体菌剂的保护剂种类与配比，筛选固体菌剂的最佳载体，初步应用固体菌剂并评价修复效果。研究结果表明：（1）向液体菌剂中添加合适的保护剂（0.30% 柠檬酸钠、0.20% 羧甲基纤维素、0.10% CaCl2）可使活菌数提高37.25%，保存30 d的液体菌剂对50 mg/L苄嘧磺隆的降解率为94.25%。（2）筛选出猪粪有机肥为固体菌剂的最佳载体，保存60 d时固体菌剂活菌数为7.45×107 cfu/g，对土壤中10 mg/kg苄嘧磺隆的降解率为91.22%。（3）固体菌剂的添加可有效减轻土壤中苄嘧磺隆残留对玉米的药害。     

微生物肥料的包埋固定化研究

为了克服单种材料包埋的不足,提高微生物肥料包埋颗粒的综合性能,本研究以海藻酸钠（SA）配合聚乙烯醇（PVA）为包埋剂,并添加适宜辅料,对复合菌体（根瘤菌解磷菌解钾菌）进行包埋固定化,以包埋操作及颗粒综合性能等为指标,筛选出较优的包埋材料组成为:SA3.0%-PVA（2.5%~3.0%）辅料（SiO24.0%CaCO30.3%）。在此条件下,操作性和成球性较好,所得包埋颗粒呈规则球形,直径为3mm～4mm,机械强度为53.4g/g～59.6g/g,包埋率为91.4%～94.3%,经过72h增殖培养颗粒的活菌数达到1011cfu/g,增殖500多倍,活菌释放率达到90%以上。     

畜禽粪便堆肥作为功能微生物载体的研究

以堆肥作为3株功能芽胞细菌液体菌剂的载体,通过优化载体含水量、温度和接种浓度等关键影响因子,以不同时间载体中有效活菌数的变化为指标,探讨堆肥代替草炭作为功能微生物载体的可行性和最适条件。研究结果表明,载体C（鸡粪）、P（猪粪）、M（1∶1鸡粪猪粪）和TP（猪粪＋草炭）在72 h内的有效活菌数均显著低于草炭;混合载体TC2（50%草炭＋50%鸡粪）和TM1（25%草炭＋75%1∶1鸡粪猪粪）的有效活菌数随着时间的延长而增加,其中72 h时TC2的有效活菌数达到11.40×109 cfu.g-1,TM1的有效活菌数达到2.64×109 cfu.g-1,均与草炭无显著差异,因此适宜代替草炭作为功能微生物的载体。采用单因素实验,载体TC2和TM1的最优化影响因子为含水量30%、吸附温度30℃、菌液接种浓度为108cfu.mL-1。     

猪血清IgG干燥方式及干燥保护剂的应用

为寻求符合实际生产需要的猪血清G型免疫球蛋白（IgG）干燥技术,该文探讨了猪血清IgG喷雾干燥的可行性和热保护剂的实际作用,对不同干燥方式所得IgG产品活性和纯度进行了对比研究。结果表明：20%（m/V）的脱脂乳粉、0.5%（m/V）的甘氨酸和5%（m/V）的麦芽糖混合后作为热保护剂能够有效地减少喷雾干燥时IgG的活性损失;海藻糖能够降低IgG冷冻干燥时的活性损失。干燥方式和是否添加保护剂决定了产品中IgG的含量和活性保留率的高低。     

嗜酸乳杆菌微胶囊的热稳定性及热动力学研究

为了使嗜酸乳杆菌微胶囊得到较好的应用，并为其保质期提供理论依据，根据其活菌数，对嗜酸乳杆菌微胶囊的热稳定性和热动力学进行分析研究。结果显示：在试验温度为45～60℃下，微胶囊的失活常数随温度的升高逐渐增大，90%微胶囊中的菌失活所需要的时间(D)分别为140.85 h、64.52 h、31.06 h及14.40 h，且在45～60℃范围内，D值变化90%时的温度变化量(Z)为15.20℃；利用Arrhenius方程计算出表观活化能(E)为124.43 kJ/mol。     

高活菌数复合益生菌发酵乳工艺优化

益生菌发酵乳中的活菌数是保证其功能特性的关键因素,为提高益生菌发酵乳中的活菌总数,以干酪乳杆菌和双歧杆菌复合菌种为试验对象,以发酵过程中的pH值和吸光度平均值值为试验指标,在单因素试验的基础上,利用 Box-Benhnken中心组合试验和响应面分析法研究了接种量、益生菌接种比例、发酵温度、葡萄糖添加量以及大豆多肽添加量对发酵乳pH值和活菌数的影响,并建立了复合益生菌发酵模型。响应面优化试验结果表明复合益生菌发酵的最佳工艺条件是脱脂乳乳固体质量分数为12%,接种量为6%,干酪乳杆菌：双歧杆菌接种体积比为3∶1,葡萄糖添加量为2.9%,大豆多肽添加量为0.8%,发酵温度为34℃,在此条件下预测值为1.076,验证试验得到实际值为1.087,与理论预测值相比,相对误差为1.0%。发酵乳最大活菌数为4.1×1011 cfu/mL,与已有研究相比,活菌数提高了1-2个对数级。在4℃条件下贮藏21 d后,发酵乳的活菌数仍然保持在4.7×1010 cfu/mL。研究结果为工业化生产高活菌数的益生菌饮料提供参考。     

组合浸渍和超低温冻融预处理对真空冷冻干燥蓝莓品质的影响

为探究组合浸渍冻干保护剂（海藻糖-CaCl₂）和超低温冻融预处理对蓝莓活性物质和品质的影响，该研究以直接干燥为对照组，以普通冻融（−20±0.5 ℃）、超低温快速冻融（−80±0.5 ℃）、超声波辅助冻干保护剂浸渍冻融（−20±0.5 ℃、−80±0.5 ℃）预处理后进行真空冷冻干燥为试验组，比较分析蓝莓活性物质（多酚氧化酶和过氧化物酶活性）、营养物质（维生素 C、花青素、总酚、类黄酮）、质构特性（硬度、咀嚼性）等指标的变化情况，并在此基础上进行Box-Behnken三因素三水平试验设计。结果表明：单一的冻干保护剂浸渍处理或者超低温处理均不如两者组合效果理想，两者相组合的浸渍后−80 ℃冻融处理可以有效维持蓝莓硬度，提高蓝莓营养物质的保留度并减少真空冷冻干燥时间。冻融次数为2次，浸渍时间为3.7 h，单次冷冻时间为4.2 d 时蓝莓综合指标最高，营养物质保留度最高。本文阐述了冻干保护剂浸渍预处理与超低温冻融两者联合处理对真空冷冻干燥蓝莓品质提升的机理，探究了冻融次数、冷冻时间、浸渍时间对品质的影响，得出了真空冷冻干燥预处理的最佳参数，为蓝莓真空冷冻干燥技术的发展提供了新思路。     

Chitosan-alginate microcapsules for oral delivery of egg yolk immunoglobulin (IgY)

Chitosan-alginate microcapsules were evaluated as a method of oral delivery of IgY antibodies. Physical characteristics, encapsulation efficiency (EE%), the loading capacity for IgY (IgY loading percentage, %, w/w of microcapsules), gastro-resistance, and release characteristics of these microcapsules in vitro under varying pH were investigated. Optimum physical factors were established for preparation of homogeneous, spherical, and smooth microcapsules. IgY loading% was not significantly altered by pH of the encapsulation medium. Encapsulation efficiency was highest (73.93%) at a pH of 3.5, above which EE% decreased significantly (p < 0.05). IgY was released from microcapsules upon exposure to simulated intestinal fluid (SIF, pH 6.8), and decreasing pH increased significantly IgY release (p < 0.05). The stability of IgY in simulated gastric fluid (SGF, pH 1.2) was greatly improved by encapsulation in chitosan-alginate microcapsules, and the residual activity was not affected by pH of the encapsulation medium. Moreover, microencapsulated IgY was significantly resistant to pepsin hydrolysis. This approach may enable intact IgY to reach target microorganisms within the lower digestive tract.     

Structural changes in natural actomyosin and surimi from ling cod (Ophiodon elongatus) during frozen storage in the absence or presence of cryoprotectants

Surimi and natural actomyosin (NAM) from ling cod (Ophiodon elongatus) were subjected to frozen storage in the absence or presence of cryoprotectants (sorbitol, sucrose, lactitol, and Litesse, either individually or in combination). Effects of frozen storage were studied for NAM frozen at -10 degrees C for 10 days and for surimi after eight freeze-thaw cycles. A commercial blend cryoprotectant (4% sucrose and 4% sorbitol), individual cryoprotectants at 8%, and optimal blends at 4, 5.5, 6, and 8%, were effective in maintaining the gel strength of surimi and NAM gels. Surimi or NAM frozen in the absence of cryoprotectants or with only 4% individual cryoprotectants, showed increased percent alpha-helical content by Raman analysis. Increased disulfide content was also observed in the treatment without cryoprotectants by the Raman SS stretching band and by chemical determination. Tyrosine residues were in a buried environment before and after freezing for all treatments, and surface hydrophobicity measured by 1-anilinonaphthalene-8-sulfonate decreased after frozen storage in the absence of cryoprotectants.     

植物乳杆菌对苏尼特羊肠道菌群、血浆代谢物及肉品质的影响

为了研究植物乳杆菌对苏尼特羊肠道菌群、血浆代谢物和肉品质的影响及其作用机理,选取三月龄苏尼特羊为试验对象,随机分为2组：对照组（C组,基础日粮）和植物乳杆菌组（R组,基础日粮、活菌数为3×1010cfu/g植物乳杆菌）,进行为期90 d的饲喂试验。屠宰后取其肠道内容物及背最长肌,利用高通量测序技术、代谢组学液相-色谱联用技术等对苏尼特羊肠道菌群、血浆代谢物及肉品质进行测定,探究肠道菌群与血浆代谢物之间的关系。结果表明：饲喂植物乳杆菌显著提高了肠道拟杆菌门（Bacteroidetes）、疣微菌门（Verrucomicrobia）、拟杆菌属（Bacteroides）、克里斯滕森菌科（Christensenellaceae_R-7_group）、理研菌科RC9肠道群（Rikenellaceae_RC9_gut_group）和瘤胃球菌（Ruminococcaceae_UCG-010）的丰度（P<0.05）,减少了厚壁菌门（Firmicutes）、变形菌门（Proteobacteria）、另枝菌属（Alistipes）和普雷沃氏菌科UCG-003菌属（Prevotellaceae_UCG-003）的丰度（P<0.05）。血浆代谢组分析结果显示植物乳杆菌显著增加了吲哚-3-丙酸、皮质醇、甘氨胆酸、L-精氨酸等含量（P<0.05）,降低了3-羟基月桂酸含量（P<0.05）。通过相关性分析发现,肠道中Bacteroidetes、Prevotellaceae_UCG-001均与血浆代谢物甘氨胆酸呈显著正相关（P<0.05）。此外,在肉品质分析中植物乳杆菌显著提高了肉的亮度值（L*）、黄度值（b*）、pH24h值（P<0.05）,显著降低肉的蒸煮损失、剪切力（P<0.05）。由此可见,日粮添加植物乳杆菌能够通过改变苏尼特羊肠道菌群结构,调节血浆代谢物参与机体脂肪代谢,进而改善羊肉品质,试验结果为今后提高蒙古羊肉品质提供理论参考。     

Impact of extra virgin olive oil and ethylenediaminetetraacetic acid (EDTA) on the oxidative stability of fish oil emulsions and spray-dried microcapsules stabilized by sugar beet pectin

The influence of EDTA on lipid oxidation in sugar beet pectin-stabilized oil-in-water emulsions (pH 6, 15% oil, wet basis), prepared from fish oil (FO) and fish oil-extra virgin olive oil (FO-EVOO) (1:1 w/w), as well as the spray-dried microcapsules (50% oil, dry basis) prepared from these emulsions, was investigated. Under accelerated conditions (80 °C, 5 bar oxygen pressure) the oxidative stability was significantly (P < 0.05) higher for FO and FO-EVOO formulated with EDTA, in comparison to corresponding emulsions and spray-dried microcapsules formulated without EDTA. The EDTA effect was greater in emulsions than in spray-dried microcapsules, with the greatest protective effect obtained in FO-EVOO emulsions. EDTA enhanced the oxidative stability of the spray-dried microcapsules during ambient storage (~25 °C, a(w) = 0.5), as demonstrated by their lower concentration of headspace volatile oxidation products, propanal and hexanal. These results show that the addition of EDTA is an effective strategy to maximize the oxidative stability of both FO emulsions and spray-dried microcapsules in which sugar beet pectin is used as the encapsulant material.     

鱼油微胶囊射流空化制备工艺优化及理化性质研究

研究目的是以大豆分离蛋白为壁材,对射流空化制备鱼油微胶囊的工艺进行优化。采用喷雾干燥法,研究壁材添加量、乳化剂添加量、芯材添加量及射流空化处理时间对乳液稳定性和鱼油微胶囊包埋率的影响,通过响应面试验分析各因素,得到最优微胶囊制备工艺,并对制备的微胶囊产品同市售产品的结构、理化特性及稳定性进行对比分析。结果表明:在壁材添加量3.21%、乳化剂添加量0.21%、芯材添加量19.70%、射流空化处理时间11.25 min工艺条件下得到的乳液稳定性较好,鱼油微胶囊的包埋率达到94.14%。微胶囊产品微观结构呈球形颗粒,结构致密,颗粒形态完整,粒径小,表面含油率较低,包埋效果好;水分含量为3.07%,溶解度为96.30%,休止角为40.39?,溶解性较好;差示扫描量热分析结果显示,微胶囊热溶解温度较高,可用于常温贮藏。包埋后的鱼油经加速贮藏试验表明微胶囊化可以提高鱼油的氧化稳定性,延长鱼油贮藏期。     

Retention of a European pear aroma model mixture using different types of saccharides

Eight types of microcapsules of European pear (La France) aroma model mixture were prepared, and their retained aroma components and sample microstructures (both surface and cross-section) were compared. The La France pear aroma model mixture was prepared by the mixing of hexanal and five kinds of esters. alpha-Cyclodextrin (alpha-CD), gum arabic (GA), soybean soluble polysaccharide (SSPS), and highly branched cyclic dextrin (HBCD) were used as carrier solids, and spray drying and freeze drying comprised the drying methods. The mean particle size of the microcapsules ranged from 8.34 microm for the microcapsules with alpha-CD to 9.67 microm for those with SSPS. The total aroma contents were different depending upon the microencapsulation systems (1.35 g/100 g of microcapsules for the spray-dried microcapsules with HBCD to 14.1 g/100 g of microcapsules for the freeze-dried microcapsules with GA). The microcapsules with alpha-CD and GA were stable against heat treatment (40, 80, or 120 degrees C for 60 min) under nitrogen gas flow.     

In vitro study of microencapsulated isoflavone and beta-galactosidase

This study was designed to find the optimum conditions for isoflavone or beta-galactosidase microencapsulation and to examine the release efficiency of microcapsules in simulated gastrointestinal conditions. Coating materials were either medium-chain triacylglycerol (MCT) or polyglycerol monostearate (PGMS). The highest rate of microencapsulation was found at 15:1 (w/w) ratio of MCT to isoflavone or beta-galactosidase as 70.2 or 75.4%, respectively. When PGMS was used as the coating material, 91.5% beta-galactosidase was microencapsulated with 15:1 mixture (w/w). In vitro study, less than 6.3-9.3% of isoflavone was released in simulated gastric fluid (pH 2-5) during 1 h incubation. Comparatively, isoflavone release increased dramatically to 87.8% at pH 8 for 1 h incubation in simulated intestinal fluid and was maintained thereafter. The release of beta-galactosidase showed a similar trend to that of isoflavone. It appeared in the range of 12.3-15.2% at pH 2-5; however, it increased significantly to 80.6% as the highest value at pH 8. Among the released isoflavones, 53.5% was converted into the aglycone form of isoflavone at pH 8 for 3 h incubation. The present study indicated that isoflavone or beta-galactosidase could be microencapsulated with fatty acid esters and released effectively in simulated intestinal condition.     

Storage stability of microencapsulated cloudberry ( Rubus chamaemorus ) phenolics

Cloudberries ( Rubus chamaemorus ) contain phenolics (mainly ellagitannins), which have recently been related to many valuable bioactivity properties. In general, phenolics are known to react readily with various components, which may create an obstacle in producing stable functional components for food and pharmaceutical purposes. In this study, the aim was to improve the storage stability of cloudberry phenolic extract by microencapsulation. The phenolic-rich cloudberry extract was encapsulated in maltodextrins DE5-8 and DE18.5 by freeze-drying. Water sorption properties and glass transition temperatures (T(g)) of microcapsules and maltodextrins were determined. Microcapsules together with unencapsulated cloudberry extract were stored at different relative vapor pressures (0, 33, and 66% RVP) at 25 degrees C for 64 days, and storage stability was evaluated by analyzing phenolic content and antioxidant activity. Compared to maltodextrin DE18.5, maltodextrin DE5-8 had not only higher encapsulation yield and efficiency but also offered better protection for phenolics during storage. Without encapsulation the storage stability of cloudberry phenolics was weaker with higher storage RVP. Microencapsulation improved the storage stability of cloudberry phenolics. The physical state of microcapsules did not have a significant role in the stability of cloudberry phenolics because phenolic losses were observed also in amorphous glassy materials. The antioxidant activity of the microencapsulated cloudberry extract remained the same or even improved slightly during storage, which may be related to the changes in phenolic profiles.     

果蔬复合固体饮料的制备及其对小鼠肝性骨病的预防作用

为开发一种感官营养俱佳的保健食品，该研究以欧李、猕猴桃、胡萝卜、葡萄、柑橘5种果蔬为原料，用喷雾干燥法制备复合固体饮料（以下简称“五果粉”），后以五果粉饲喂雌性C57小鼠，测定血清指标，分析骨微结构，探究其对高脂饮食诱导的小鼠肝性骨病的预防作用，为五果粉的制作和营养保健功能提供依据。结果表明：5种果蔬的配方比例为40%欧李、20%猕猴桃、20%胡萝卜、10%柑橘、10%葡萄。添加可溶性固形物总量的40%的复合助干剂（麦芽糊精∶分离乳清蛋白=30∶10）与3%的稳定剂羧甲基纤维素钠，喷雾干燥条件：进风温度126℃、进料速度6.3m L/min、转子流量计高度44.00mm、可溶性固形物含量11.00%，在该条件下生产的五果粉集粉率60.86%。血清试验结果表明，给药组小鼠血清中骨钙素和抗酒石酸酸性磷酸酶5b的水平显著低于模型组（P<0.05）；超氧化物歧化酶和谷胱甘肽过氧化物酶水平显著高于模型组（P<0.05），丙二醛水平显著低于模型组（P<0.05）；谷丙转氨酶、谷草转氨酶水平显著低于模型组（P<0.05），且与空白组相比无显著差异（P>0.05）；总胆固...