魔芋超强吸水剂在奶茶粉中的抗结性能研究

测试了魔芋超强吸水剂(KSAP)和二氧化硅的吸湿和保水性能,并比较了二者在奶茶粉中不同剂量的抗结性能.结果表明:在RH=90%±3%、T=25±1℃的高湿环境中放置3个月,奶茶粉添加2.5‰的KSAP抗结性能优于添加2.5‰的二氧化硅,其流动性指数为62.5,水分活度为O.385;在奶茶粉中,KSAP比二氧化硅更具有竞争吸湿抗结的优势.     

魔芋超强吸水剂吸湿性能研究

通过与变色硅胶和蒙脱石进行比较,研究了魔芋超强吸水剂(KSAP)在不同湿度环境下的吸湿性能,同时对它们进行了解吸性能比较,了解它们在吸湿后的保水性能。结果表明,在RH=30%±1%,T=25±1℃时,硅胶和蒙脱石的吸湿性较好;在RH=75%±1%,T=25±1℃和RH=90%±1%,T=25±1℃的环境中,硅胶和蒙脱石在1d前较KSAP高,但之后KSAP的吸湿性表现较好,9d时吸湿率分别达到70%和120%,且保水能力好。     

鸡粉调味料工业化生产抗结块试验研究

采用静止角度测试法,在工业化条件下进行鸡粉调味料抗结块性能试验.考察了干燥温度、产品粒度、抗结剂添加量及蔗糖粉末添加量对鸡粉调味料抗结块性能的影响,并在单因素试验的基础上进行抗结块正交试验.结果表明,影响产品抗结块性能的因素从大到小依此为:蔗糖粉末添加量＞产品粒度＞干燥温度＞抗结剂添加量;最佳条件为:蔗糖粉末添加量4%(W:W),干燥温度90℃,产品粒度50目,抗结剂添加量0.50%(W:W).     

调味盐的抗吸湿结块性能评价

研究通过检测结块率、结块强度、水分含量、吸湿率,对调味盐和未添加抗结剂食盐的抗结块性能进行对比分析,从而评价调味盐的抗吸湿结块性能。结果表明,未添加抗结剂食盐结块率、水分含量都随着加速时间的增加逐渐上升,而调味盐的结块率、水分含量都随着加速时间的增加几乎不变;调味盐和未添加抗结剂食盐在湿度小于75%时,都有很好的抗吸湿性能,在湿度大于75%时,随着时间的增加,调味盐的吸湿率比未添加抗结剂食盐增加得更慢。调味盐比未添加抗结剂食盐具有更好的抗吸湿结块性能。     

响应面法优化枸杞粉抗结块工艺

利用响应面法分析吸湿时间、干燥剂添加量和抗结剂添加量对枸杞粉的抗结块效果,并探讨了包装方式及材料对枸杞粉结块度的影响。结果表明,在单因素实验中干燥剂与抗结剂对减缓枸杞粉结块的效果明显,根据单因素试验结果,进行响应曲面分析,以结块度为指标对枸杞粉抗结块的条件进行优化,通过多元回归拟合得到影响结块度因素依次为:Si O_2添加量吸湿时间 CaCl_2添加量。枸杞粉吸湿结块过程中抗结块的最优条件为:添加CaCl_2质量分数为0. 06%、添加Si O_2质量分数为1. 00%、吸湿时间为12 d,在此条件下实际测得结块度为48. 73%。在最佳抗结块条件下,真空包装抗结块效果优于非真空包装,在同一真空度下,不同包装材料对枸杞粉抗结块的效果依次为聚乙烯透明塑料包装(PE)牛皮凝膜纸包装(牛皮纸/PE)铝箔复合膜包装(铝箔/PE)。     

真空微波干燥蜂蜜粉配方的研究与优化

在蜂蜜粉中添加抗吸湿剂麦芽糊精和抗结剂磷酸三钙,以解决蜂蜜粉的强吸湿性和结块性而导致其包装贮存困难的问题。通过单因素实验选择蜂蜜粉非水溶性抗结剂和抗吸湿剂的添加范围;以吸湿率和结块度作为评价指标,通过回归分析实验,确定线性回归方程和非线性回归方程,优化抗结剂和抗吸湿剂配比。通过实验与分析,得出结果每克固体蜂蜜粉麦芽糊精添加0.42~0.43 g,磷酸三钙添加0.023~0.025 g,蜂蜜粉结块度和吸湿率分别为:HG=5.40%~5.65%,DC=10.29%~12.93%。     

枣粉抗结块实验研究

为了防止枣粉结块,对影响其结块的去核干枣水分含量、磨粉环境相对湿度、抗结剂的种类及添加量、枣粉粒度、内包装方式等因素进行研究.结果表明,枣粉抗结的最佳工艺条件为去核干枣水分含量在3％以下,磨粉环境相对湿度控制在30％～35％,复合抗结剂为0.7％微晶纤维素+0.6％二氧化硅+0.7％磷酸三钙,枣粉的粒度为120目或140目,内包装充气量为30％.     

奥尔良调味料抗结性试验研究

为了防止奥尔良调味粉结块,对影响其结块的麦芽糊精添加量、白砂糖添加量、抗结剂种类及添加量、搅拌时间、包材等因素进行研究。结果表明:二氧化硅抗结效果优于硅酸钙,奥尔良调味料中的最佳添加比例为麦芽糊精5%、二氧化硅0.8%、白砂糖10%;包材透氧率不能大于6m L/m2.d,搅拌时间6 min。     

低共熔溶剂结合球磨工艺制备MCC及其在片剂中的应用性能研究

采用氯化胆碱/甲酸（ChCl/FA）、氯化胆碱/草酸（ChCl/OA）、氯化胆碱/柠檬酸（ChCl/CA）3种低共熔溶剂（DES）处理杨木溶解浆,结合球磨处理制备微晶纤维素（MCC）,探讨了不同DES体系下时间、温度对MCC聚合度、粒径等性能的影响;并以布洛芬为模型药物,将MCC作为药用辅料填充在布洛芬片中,研究了MCC粒径及用量对片剂崩解时间、累积释放率等性能的影响。结果表明,ChCl/FA体系在100℃、60 min时制备的MCC流动性最好;在不添加崩解剂的情况下,当MCC填充量为35.0%时,片剂的崩解时间为190 s,60 min内累积释放率可达86.58%,且具有较高的硬度和抗张强度,显示出DES法制备的MCC用作药用辅料具有良好的填充效果。     

酪蛋白和工艺对再制稀奶油稳定性的影响

本研究主要通过测定再制稀奶油的粒径、界面蛋白含量、黏度、微流变性质分析胶束酪蛋白浓缩粉(micelle casein concentrate,MCC)、酪蛋白酸钙(calcium caseinate,CaC)粉及工艺(灭菌、二次均质)对再制稀奶油稳定性的影响。结果表明:蛋白添加量为1.0%(质量分数,后同)和2.0%时,MCC再制稀奶油的失稳系数分别为0.396±0.011、0.032±0.001,说明稳定性随蛋白添加量的增加而提高,而CaC再制稀奶油稳定性的变化规律与之相反。灭菌后,MCC再制稀奶油脂肪球粒径D3,2、界面蛋白含量及黏度显著增加(P0.05),均方根位移(mean square displacement,MSD)明显降低,CaC再制稀奶油与MCC再制稀奶油的变化明显不同,除界面蛋白含量由3.9～5.5 mg/m~2增至5.2～7.0 mg/m~2外,粒径D3,2、黏度及MSD(2.0%CaC再制稀奶油除外)无明显变化。二次均质后,MCC再制稀奶油脂肪球粒径D3,2、界面蛋白含量及黏度显著下降(P0.05),MSD明显增加,而CaC再制稀奶油样品中除1.0%CaC再制稀奶油粒径D3,2由(2.80±0.10)μm下降至(2.06±0.11)μm外,其他理化性质变化不明显。虽然MCC乳化能力较CaC低,但其在添加量2.0%时制备的稀奶油稳定性最好。工艺会导致再制稀奶油(尤其是MCC再制稀奶油)理化性质间平衡的改变,再制稀奶油的稳定性也随之改变。     

500米~3生物反应器K_(La)的测定技术

在500米~3活性污泥生物反应器中,用动态测量法测定氧的体积传递系数(K_L a),本文提供了一种简便方法。这种方法对有机废水处理有实用意义。     

Arsenic(III) oxidation by iron(VI) (ferrate) and subsequent removal of arsenic(V) by iron(III) coagulation

We investigated the stoichiometry, kinetics, and mechanism of arsenite [As(III)] oxidation by ferrate [Fe(VI)] and performed arsenic removal tests using Fe(VI) as both an oxidant and a coagulant. As(III) was oxidized to As(V) (arsenate) by Fe(VI), with a stoichiometry of 3:2 [As(III):Fe(VI)]. Kinetic studies showed that the reaction of As(III) with Fe(VI) was first-order with respect to both reactants, and its observed second-order rate constant at 25 degrees C decreased nonlinearly from (3.54 +/- 0.24) x 10(5) to (1.23 +/- 0.01) x 10(3) M(-1) s(-1) with an increase of pH from 8.4 to 12.9. A reaction mechanism by oxygen transfer has been proposed for the oxidation of As(III) by Fe(VI). Arsenic removal tests with river water showed that, with minimum 2.0 mg L(-1) Fe(VI), the arsenic concentration can be lowered from an initial 517 to below 50 microg L(-1), which is the regulation level for As in Bangladesh. From this result, Fe(VI) was demonstrated to be very effective in the removal of arsenic species from water at a relatively low dose level (2.0 mg L(-1)). In addition, the combined use of a small amount of Fe(VI) (below 0.5 mg L(-1)) and Fe(III) as a major coagulant was found to be a practical and effective method for arsenic removal.     

Control potential of Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) against Lasioderma serricorne (F.) (Coleoptera: Anobiidae)

The control potential of Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) against Lasioderma serricorne (F.) (Coleoptera: Anobiidae) was evaluated in laboratory. The longevity and progeny production of A. calandrae were investigated at 25, 30, and 35 °C. Parasitism preference of A. calandrae to different life stages of L. serricorne was studied at the parasitoid-to-host ratio of 1:15. Effectiveness of A. calandrae against L. serricorne larvae was investigated at different parasitoid-to-host ratios of 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, and 1:40 for 24, 48, and 72 h at a photoperiod of 12:12 (L:D) h, 28 ± 2 °C, and 75 ± 5% RH. Effectiveness of A. calandrae against L. serricorne larvae was also evaluated at different volumes (10, 55, 100, 150, 200, 250, 1500, and 2800 ml) of glass vials when the parasitoid-to-host ratio was 1:15. The favorable temperature for survival and progeny production of female A. calandrae was 25 °C. Female A. calandrae could parasitize mature larvae of L. serricorne and produce their offspring during the whole adult stage of the wasp. Female A. calandrae could control 3-, 4-, 5-, and 6-week-old mature larvae and pupae of L. serricorne. Anisopteromalus calandrae offspring only emerged from 6-week-old mature larvae and pupae of L. serricorne. The parasitoid-to-host ratio and space size dramatically affected the parasitism rate of A. calandrae against L. serricorne and the number of A. calandrae offspring. These results suggest that A. calandrae has great potential for controlling L. serricorne infestation.     

Iron(VI) and iron(V) oxidation of copper(I) cyanide

Copper(Il) cyanide (Cu(CN)4(3-)) in the gold mine industry presentsthe biggest concern in cyanide management because it is much more stable than free cyanide. Cu(CN)4(3-) is highlytoxic to aquatic life; therefore, environmentally friendly techniques are required for the removal of Cu(CN)4(3-) from gold mine effluent. The oxidation of Cu(CN)4(3-) by iron-(VI) (FeVIO4(2-), Fe(VI)) and iron(V) (FeVO4(3-), Fe(V)) was studied using stopped-flow and premix pulse radiolysis techniques. The stoichiometry with Fe(VI) was determined to be 5HFeO(4-) + Cu(CN)4(3-) + 8H2O - > 5Fe(OH)3 + Cu2+ + 4CNO- +3/202 + 6OH-. The rate law for the oxidation of Cu(CN)4(3-) by Fe(VI) was found to be first-order with each reactant. The rates decreased with increasing pH and were mostly related to a decrease in concentration of reactive protonated Fe(VI) species, HFeO4-. A mechanism is proposed that agrees with the observed reaction stoichiometry and rate law. The rate constant for the oxidation of Cu(CN)4(3-) by Fe(V) was determined at pH 12.0 as 1.35 +/- 0.02 x 10(7) M(-1) s(-1), which is approximately 3 orders of magnitude larger than Fe(VI). Results indicate that Fe(VI) is highly efficient for removal of cyanides in gold mill effluent.     

Attractancy of diethyl ether extracts of Arachis hypogaea (Linnaeus) (Papilionaceae), Citrullus lanatus (Thunberg) (Cucurbitaceae) and Irvingia gabonensis var. excelsa (Baillon) (Irvingiaceae) to Oryzaephilus mercator (Fauvel) (Coleoptera: Silvanidae)

Volatiles of the diethyl ether extracts of I. gabonensis, C. lanatus and A. hypogaea attracted 1–7 and 28–42-day-old adult O. mercator when tested in a two-choice pitfall Petri dish bioassay. For both age groups, a significant difference was observed in response between fed and starved adults to the different extracts. Differences in starvation time did not affect responses of individuals in the 1–7-day-old group; a significant effect was observed in the 28–42-day-old group.

Adults, 28–42-day-old were significantly more responsive to virtually all extracts than 1–7-day-old adults. Responses of adults in each age group to the different extracts were not significantly different. The time of trial within the period 0900–1900 h did not significantly affect the response of adults in both age groups, starved for 2 days, to any extract.     

Interaction of Phytic Acid with the Metal Ions, Copper (II), Cobalt (II), Iron (III), Magnesium (II), and Manganese (II)

The combination of phytic acid with the metal ions of cobalt (II), magnesium (II), manganese (II), copper (II), and iron (III) has been investigated. With the experimental conditions used, in all cases, the products isolated were amorphous powders with nonstiochiometric atomic ratios.     

Mind the (yield) gap(s)

This paper explores the origin of the notion of ??yield gap?? and its use as a framing device for agricultural policy in sub-Saharan Africa. The argument is that while the yield gap of policy discourse provides a simple and powerful framing device, it is most often used without the discipline or caveats associated with the best examples of its use in crop production ecology and microeconomics. This argument is developed by examining how yield gap is used in a selection of recent and influential agricultural policy documents. The message for policy makers and others is clear: ??mind the (yield) gap(s)??, for they are seldom what they appear.     

Supercritical fluid extraction (SFE) of 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI) from ground-coffee with high-performance liquid chromatographic-electrospray mass spectrometric quantification (HPLC/ESI-MS).

Two polar analytes, 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI), were extracted with supercritical carbon dioxide (CO2) modified with aqueous methanol. The method was applied to a roasted coffee powder with good recovery rates. Method efficiency was compared with that of solid-phase extraction using SCX Disc cartridges and validated for spiked solid matrix. The analytes were determined using isocratic liquid chromatography-mass spectrometry (LC/MS) on an Atlantis HILIC Silica column (150 x 2.1 mm, 3 microm) with 80% methanol and 20% 0.01 mol l-1 ammonium formate as the mobile phase. The limit of quantification was around 1.5 pg for 4-MeI and 2.0 pg for THI. The linearity of the calibration curves was satisfactory as indicated by correlation coefficients of >0.999. The coefficient of variation for the intra-day and inter-day precisions was <4% (n = 6). Accuracy was in the range 98-101%; recovery rates were > or = 98 and > or = 99% for THI and 4-MeI, respectively. Several samples of Arabica coffee from various locations and commercially available 'off-the-shelf' coffee products (Arabica/Robusta mixtures) were analysed to test the method.     

Role of transition metals,Fe(II), Cr(II), Pb(II), and Cd(II) in lipid peroxidation

Cod liver oil was oxidized with Fenton-like systems containing transition metals Fe(II), Cr(II), Pb(II), and Cd(II). Malonaldehyde (MA) formed from 10 μl cod liver oil oxidized by a Fenton-like system containing each metal at levels of 0.25, 0.5, 1 and 4 μmol was analyzed by a gas chromatograph equipped with a nitrogen phosphorus detector. The MA production exhibited dose response and the greatest amount (837.0 ± 19.1 nmol) was obtained by the Fe(II) system at the level of l μmol. Generally, higher MA formation is observed in the lower the third ionization potential of the metal. The decreasing order of MA formed in the metal systems at the level of 1 μmol is Fe(II) > Cr(II)(274.1 ± 20.1 nmol) > Pb(II)(150.7 ± 13.0 nmol) > Cd(II)(95.4 ± 6.7 nmol). The amounts of MA formed in Cr(II), Pb(II), and Cd(II) systems were considerably lower than those in the Fe(II) system. The relative formations of MA in the Cr(II) and Pb(II) systems were similar to those in the Fe(II) system. The results suggest that trace amounts of metals contribute oxidative effects to lipid peroxidation followed by various diseases.     

Peroxidase from oranges (Citrus sinenses (L.) Osbeck

Soluble peroxidase was extracted from oranges (Citrus sinenses (L.) Osbeck). Small amounts of purified anionic and cationic isoperoxidases have been obtained by gel filtration and ion-exchange chromatography. It has been shown that peroxidase activity present in crude extracts of oranges (juice, albedo, and peel) is less stable to heat than the enzymes activity of highly purified individual orange isoperoxidases. For the purified isoperoxidases heat-inactivation is still non-linear. It is suggested that this may be due to micro heterogeneity in covalently bound oligosaccharide residues at the molecular level. The higher activity was detected in the crude extract from the peel, around 3.2 and 7.8 times more than the fractions from the albedo and juice respectively. The crude soluble peroxidase fractions were particularly heat stable. The pI (4.5, 5.2, and 9.0) of the purified isoperoxidase (A₁, A₃, and C₁) from the peel soluble fraction was measured using a surface electrode and the molecular weight (42 kDa, 30 kDa, and 26 kDa) was estimated by gel-filtration.