槐花汁饮料的制作及其感官品质的模糊综合评价

采用正交实验等方法研究了槐花汁饮料的制作工艺及产品配方.实验结果表明,槐花汁浸提工艺的最佳条件:浸提温度90℃,浸提时间3 h,料液比1∶5;在该条件下,槐花汁饮料中芦丁含量最高,达到5.3341μg/m L.其最佳配方:麦芽糖醇含量2.3%,柠檬酸含量0.07%,甜蜜素含量0.05%;在该条件下,槐花汁饮料感官品评分数最高,约9.25分,感官品质为优,属于Ⅰ级.槐花汁饮料中可溶性固形物1.0%,总酸0.02%,菌落总数30个/m L,大肠菌群1个/m L,致病菌未检出.     

衡阳某高校桶装水中菌落总数及大肠菌群的检测结果分析

对衡阳某高校桶装水中菌落总数及大肠菌群的超标状况进行研究,以促进企业微生物污染的有效预防和控制,提高学生和老师饮用纯净水的卫生质量。采用随机抽样的方法采集某高校桶装水样55份,按照GB4789.2-2003及GB4789.3-2003对水样进行培养和检测。结果显示在55份水样中菌落总数超标50份,大肠菌群超标34份,菌落总数超标率为90.91%,大肠菌群超标率为61.82%。     

红薯馒头营养成分分析

为了探究红薯馒头的营养价值,测定并比较了红薯馒头和普通馒头的基本营养成分。结果表明:在相同工艺条件下,普通馒头的蛋白质含量为0.85 mg/100g,总糖为17.5 g/100g,还原糖含量为25.38%,水分含量为15.1%,多酚含量为0.295 g/100g。红薯馒头的蛋白质含量为3.75 mg/100g,总糖含量为38.1 g/100g,还原糖含量为31.25%,水分含量为17.2%,多酚含量为0.310 g/100g。红薯馒头中比普通馒头还原糖含量增加了23%,总糖含量增加了118%,蛋白质含量增加了341%,多酚含量增加了5%。由此可见,红薯馒头的制作不仅提高了普通馒头的营养价值,而且改善了馒头的风味和质构。     

黑果腺肋花楸果制剂中有效成分测定及体外活性研究

建立黑果腺肋花楸果制剂中有效成分的含量测定方法,并对制剂清除亚硝酸盐的能力、抑制脲酶、α-葡萄糖苷酶、胰脂肪酶的活性进行考察.采用紫外-可见分光光度法对颗粒剂中的总黄酮、原花青素、花色苷和多糖进行含量测定及方法学验证;用半数浓度(IC₅₀值)作为指标来评价颗粒剂的不同体外活性.实验结果表明,两种颗粒剂均在显色前360 min内和显色后60 min内有良好的稳定性,重复性和精密度良好,加样回收率为98.63%～102.50%和98.27%～103.00%,且RSD<2.0%,建立的方法可满足含量测定要求.3批黑果颗粒剂和双果颗粒剂中总黄酮、原花青素、花色苷、多糖的含量平均值分别为7.27、14.10、1.56、473.95 mg/g和12.35 mg/g、3.44 mg/g、0.80 mg/g、700.12 mg/g.体外活性实验表明两种颗粒剂均具有一定的清除亚硝酸盐能力,抑制脲酶、α-葡萄糖苷酶和胰脂肪酶活性的能力.且建立的4类有效成分的含量测定方法,具有较好的重复性,回收率符合要求,可用于黑果腺肋花楸果制剂中总黄酮、原花青素、花色苷、多糖的含量测定,能为评...     

甜炼乳真空浓缩的工艺优化及指标分析

以牛奶和白砂糖为原料,通过单因素实验和正交实验确定生产甜炼乳的最佳工艺,建立粘度的测定方法;通过固形物和粘度的测定寻求二者之间的关系。对最佳工艺制作的甜炼乳进行水分、粘度、固形物、可溶性固形物、蛋白质含量的测定及感官评价。结果显示:甜炼乳制作的最佳工艺为原料乳和糖浆分别在95℃水浴锅中预热15min杀菌,待其冷却到57℃后混合浓缩,浓缩时间48min,浓缩温度40℃,真空度控制在0.1MPa。最佳工艺所得甜炼乳粘度为17.14Pa.s,水分含量为17.83%,固形物含量为82.57%,可溶性固形物含量为71.4%,蛋白质含量为9.16%,感官评价为96分。     

茶多酚-海藻酸钠涂膜对草莓的保鲜效果研究

为延长草莓的贮藏期,探讨可食用涂膜对草莓生理生化及品质的影响,本实验以海藻酸钠(0.01g/mL)作为主剂,与不同浓度茶多酚(0、0.5%、1.0%、1.5%)进行复配制成复合保鲜剂分别处理草莓样品,置于4℃保存,贮藏期间对草莓果实进行感官评定、抗坏血酸含量、可滴定酸含量、可溶性固形物含量和丙二醛含量的测定。结果表明,与单独的海藻酸钠涂层相比,茶多酚-海藻酸钠复合涂层对草莓的保鲜效果更好,且当海藻酸钠浓度为0.01g/mL,茶多酚浓度为1.0%时效果较好,在储藏第5天时仍能保持较好的感官品质,且可滴定酸、可溶性固形物和VC的损失最少,同时能有效抑制采后贮藏期间丙二醛含量的上升,为草莓的储藏保鲜提供参考。     

微生物与水体污染

2009年7月23日．内蒙古赤峰市突降暴雨致使污水侵入饮用水源井,造成污染。被污染的水源井中查出其总大肠菌群、菌落总数严重超标．同时还检出了沙门氏菌。不少市民由于饮用了被污染了的水而导致腹泻、呕吐。     

怀化市城郊稻田土壤相关因素的研究

对怀化市城郊的稻田土壤一些相关因素进行研究,了解这些因素对土壤肥力及作物生长的影响.采用平板计数法对土壤中微生物总数进行计数,直接对风干土样进行水分的检测、用酸度计对土样进行pH检测、对土壤中脲酶及多酚酶进行检测及用重铬酸钾容量法检测有机质含量.试验结果为:土壤中酵母茵数量为4.5×106 cfu/g,霉菌数量为4.2×1 05 cfu/g,细菌数量为4.8×107 cfu,g,放线茵数量为3.9×106 cfu/g,固氮微生物数量为2.37×108/g,固氮微生物数量较多;土壤水分含量较低,分析基水分在26.83%～33.51%之间,干基水分在36.67%～50.40%之间;土样酸度为4.11,土壤中磷素、钼含量有效性较低,锌、铜、锰、铁、硼等营养元素的有效性较高;土样脲酶活力为0.032 mg/min,多酚氧化酶活力为0.005 mg/min.由此可见,怀化市城郊稻田土壤为含水量低、酶活力低、有机质含量低的酸性土壤.     

铜仁阳荷营养成分测定与分析

用常规方法测定阳荷主要营养成分含量。水分测定用直接干燥法,灰分测定用灰化法,蛋白质测定用分光光度法,粗脂肪测定是索氏提取法,粗纤维测定用酸碱水解法,维生素C测定用滴定法,总糖测定用苯酚硫酸法,总酸测定酸碱滴定法,氨基酸测定用全自动氨基酸分析仪法。结果表明:铜仁市售阳荷水分的含量为86%、灰分的含量为1.2 g/100g、蛋白质的含量为9.8 g/100g、粗脂肪的含量为4.12 g/100g、粗纤维的含量为16.94 g/100g、总糖的含量为2.3 g/100g、维生素C的含量为0.029 g/100g、总酸度为0.26%。用氨基酸分析仪测定出有17种氨基酸,其中必需氨基酸有7种,其总含量为3.469 g/100g,非必需氨基酸总含量为5.603g/100g,总的氨基酸含量为9.072 g/100g,其中谷氨酸含量最高。可知,该地阳荷营养价值丰富,具有一定的开发与利用价值。     

茶粕提取物对巨峰葡萄的采后保鲜效果研究

本文研究不同浓度的茶粕提取物对巨峰葡萄采后果实的失重率、腐败率、呼吸强度、可溶性固形物、Vc及可滴酸含量等品质指标的的影响.实验结果表明茶粕提取物可以降低果实失重率、腐败率、抑制呼吸,维持可溶性固形物、Vc及可滴酸含量.茶粕提取物可以有效延长果实保质期.其中浓度30 mg/L油茶饼粕提取物保鲜效果最佳.实验第18 d时30.00 mg/L茶粕提取物失重率为6.59%、腐烂率6.70%,呼吸强度19 mgCO_2/(kg·h)、可溶性固形物16.94%、Vc4.15 mg/100g、可滴酸含量0.60%.     

A corn straw-based diet increases release of inflammatory cytokines in peripheral blood mononuclear cells of dairy cows

Recent studies have shown that diet can affect the body’s immunity. Roughage of dairy cows consists of a variety of plant materials which make different contributions to health. This study investigated the effect of different roughages on the immunity of dairy cows. Serum, peripheral blood mononuclear cells (PBMCs), and milk samples were collected from 20 multiparous mid-lactation cows fed mixed forage (MF)- or corn straw (CS)-based diets. Expression profile analysis was used to detect the differentially expressed genes (DEGs) from PBMCs. The results showed that milk protein in the MF group increased to 3.22 g/100 ml, while that of the CS group milk was 2.96 g/100 ml; by RNA sequencing, it was found that 1615 genes were differentially expressed between the CS group and the MF group among the 24 027 analyzed probes. Gene ontology (GO) and pathway analysis of DEGs suggested that these genes (especially genes coding cytokines, chemokine and its receptors) are involved in the immune response. Results were confirmed at the protein level via detecting the levels of interleukin-2 (IL-2), IL-6, IL-10, IL-12, leptin (LEP), interferon-γ (IFN-γ), transforming growth factor-β1 (TGF-β1), and tumor necrosis factor-α (TNF-α) in peripheral blood by enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay analysis. Our data supported the conclusions that the protein content in milk of the MF group was higher than that of the CS group, the CS-based diets induced more release of cytokines than the MF-based diets in dairy cows’ PBMCs, and milk protein content may be affected by cytokines.     

EDTA络合滴定法测定不同品质牛奶中钙含量

采用EDTA络合滴定法测定了不同品质牛奶中的钙含量。结果表明：伊利早餐奶钙含量最高（1.043 8mg/g）,银桥酸牛奶钙含量最低（0.958 9 mg/g）。对于同一品牌牛奶,伊利早餐奶中含钙量最高,伊利酸牛奶中含钙量最低;不同品质纯牛奶：伊利纯牛奶中的钙含量最高,古城纯牛奶中的钙含量最低。     

基于压电传感技术的鲜奶总菌数快速检测方法研究

应用压电晶体谐振技术检测鲜奶中的微生物是基于鲜奶在微生物作用下发生凝结,导致牛奶的密度和粘度发生变化,引起压电晶体频度的变化,通过检测牛奶的凝结时间实现对微生物的间接测定.这一新方法被用于牛奶中总菌数的测定,实验结果与传统的平板计数法无显著性差异,但本文方法更灵敏、快速、简便.在42℃和初始pH值为6.8的条件下,检测浓度在5.5×10^2-1×10^6cfu/mL范围内,检测时间（FDT）约为1.5-6.5小时,远少于传统的平板计数法24-48小时的检测时间.     

氮肥缓释剂对水稻土壤脲酶活性、氮素转化及产量的影响

主要研究水田使用尿素和生物肥料时，配加脲醇抑制剂以缓解尿素的集中水解，减少氨挥发和硝态氮的淋失，达到减少氮素损失的目的．试验结果表明：脲醇抑制剂对脲醇活性抑制持续时间及其尿素水解速度，随其用量增加而延长，而且随着时间的推移脲醇活性逐渐提高．当施用生物肥料时，由于土壤微生物数量大幅度增加，土壤脲醇活性增强，其抑制率略低于不施生物肥料，其它规律基本相同．     

功能型孝感麻糖生产工艺改进的研究

文章讨论了以发芽糯糙米为主要原料,经大麦芽糖化后,制得富含γ-氨基丁酸（GABA）的饴糖,再通过与炒制好的芝麻揉合,制成的功能型孝感麻糖的工艺过程。结果表明,孝感麻糖采用3．5％的干麦芽,在64℃的糖化条件下,糖化6小时糖化效果最佳;孝感麻糖产品中γ-氨基丁酸（GABA）含量≥25mg／100g,在半成品配比过程中,老糖与熟麻仁的比例为18：13时,产品口感最佳;用黑芝麻为原料制成的黑芝麻糖,以不去皮产品更受消费者青睐。     

6-甲基-2-（α-羟甲基）-1H-苯并咪唑荧光增敏探针法测定蛋白质

以6-甲基-2-（α-羟甲基）-IH-苯并咪唑（MHMBM）作为荧光探针,利用蛋白质对MHMBM荧光增敏作用,建立了测定人血清总蛋白的新方法。结果表明,在中性水溶液中,MHMBM的荧光强度与牛蛋白（BSA）的浓度呈良好的线性关系,相关系数（r）为0．9995,检出限2．3μg／mL,线性范围4．6—60．0μg／mL。本方法用于测定两种样品溶液中的总蛋白,RSD（n=6）分别为1．7％和1．3％,回收率95．5％和98．6％。     

Comparison Between MIR and NIR Spectroscopic Techniques for the Determination of Fat and Protein Contents in Milk

To compare mid-infrared(MIR)and near-infrared(NIR)spectroscopies for the determination of the fat and protein contents in milk,the same sample sets with varying concentrations of fat and protein were measured in the MIR range of 3 200-700 cm-1 and NIR range of 9 000-4 000 cm-1.The spectral features in the two regions were analyzed.The MIR spectra of milk were characteristic due to the MIR inherent molecular specificity,whereas the NIR spectra were relatively characterless due to the NIR low selectivity.Partial least squares(PLS)regression models for fat and protein were developed by using both MIR and NIR spectra.MIR data with no pretreatment gave better results than NIR data.The square correlation coefficient(R2)and the root mean square error of prediction(RMSEP)were 0.98 and 0.10 g/dL for fat and 0.97 and 0.11 g/dL for protein.With NIR techniques,satisfactory results were not obtained with raw data.However,NIR data after pretreatment gave similarly good results to the ones using MIR method.This paper indicates that either of the MIR and NIR spectral methods is reliable for the determination of the fat and protein contents.     

S2O8^2-/V2O5-CeO2型固体超强酸催化剂的制备研究

以NH4VO3为原料,（NH4）2S2O8为浸渍液,添加少量稀土Ce^4＋,用沉淀-浸渍法制备出新型S2O8^2-/V2O5-CeO2固体超强酸催化剂,以合成乙酸苄酯作为探针反应考察不同条件下制备的超强酸的催化活性。研究发现,当加入CeO2量为催化剂总量的1．0％,焙烧温度为500℃,浸渍液浓度为1．5mol／L,焙烧时间为3h时,催化剂的活性最好。     

Preparation of Glutaraldehyde Cross-Linked Chitosan Beads Under Microwave Irradiation and Properties of Urease Immobilized onto the Beads

The glutaraldehyde cross-linked chitosan beads were prepared under microwave irradiation and urease was immobilized onto the beads. The activity and the yield of enzyme activity of the immobilized urease were 10.83 U/g carrier and 47.7%, respectively. The optimum conditions of immobilization were 1% of glutaraldehyde volume fraction, 10 mg/g of urease/beads weight ratio, 24 h of the processing time and pH 6.5 of the reaction medium for immobilization. The properties of the immobilized urease were investigated and compared with those of the free enzyme. The optimum pH values were 6.5 and 7.0 for the immobilized and free urease, respectively. The optimum temperature was 60℃ for the free urease, while it shifted to 65 ℃ for the immobilized enzyme. The Michaelis constant Kr, was 9.1 mmol/L for the immobilized and 12.5 mmol/L for the free urease. The immobilized urease retained 40% of its initial enzyme activity even after 10 repeated uses. The immobilized urease stored at 4 ℃ retained 46% of its initial activity even after 35 d.     

桂西北不同寄主桑寄生科植物总黄酮含量的季节差异

为了合理利用桑寄生科药用植物资源,利用超声波辅助——乙醇浸提、三氯化铝比色法对桂西北岩溶地区广寄生、离瓣桑寄生和鞘花等3种常见的桑寄生科植物枝叶总黄酮含量的月际变化进行测定。结果表明:三种寄生被测样品的总黄酮含量分别为7.22~21.92 mg/g、22.63~58.90 mg/g和7.60~22.15 mg/g,无论寄主相同与否,不同种类的桑寄生科植物总黄酮含量均有明显差异,广寄生和鞘花的总黄酮含量相对较低且差异不大,离瓣桑寄生的总黄酮含量则明显高于前两者;不同种类寄生植物总黄酮含量的季节变化比较复杂,有双峰型、三峰型或多峰型等情况,其最大峰值出现的月份也不一致。离瓣桑寄生的生物量大,总黄酮含量较高,具有较大利用价值。