虫草液体发酵的非营养条件优化与免疫功能研究

采用中心组合设计,以菌丝体生物量为考察指标对虫草液体发酵的非营养条件进行优化,同时对菌丝体提取物的免疫功能进行了探讨。研究结果表明:当培养温度为22.64℃、pH为6.18、培养时间为7.36d时,菌丝体产量达到21.73g/L;并发现其水提取物在50～200μg/mL的剂量范围内,能够提高巨噬细胞吞噬能力和促进小鼠脾细胞的增殖,具有一定的免疫调节作用,是一种潜在的具有免疫调节功能的食品资源。     

不同采摘期及不同解冻方式对香椿香气含量的影响

为探究不同采摘期及不同解冻方式对香椿香气含量的影响,本试验对不同采摘期的香椿,经顶空固相微萃取提取香椿的挥发性组分后,用气相色谱的FPD检测器分析测定;同时对速冻香椿经3种解冻方式解冻后香椿香气的相对含量进行测定。结果表明,对不同采摘期而言,香椿特征香气随采摘期呈现先增后减的趋势,并且采摘于5月下旬的香椿香气最浓郁;对不同解冻方式而言,特征香气物质在常温解冻方式下达到最大值,且冻藏处理及解冻对物质A的影响较大。     

Removal of reactive blue 19 and reactive blue 49 textile dyes by citrus waste biomass from aqueous solution: Equilibrium and kinetic study

The purpose of this study was to establish the potential of inexpensive and locally available biomaterial, that is, lignocellulosic waste of Citrus sinensis as biosorbent to remove reactive anthraquinone dyes from aqueous solution. The effects of immobilisation and chemical treatment of biosorbent were also explored for the enhanced sorption of dyes. Biosorbent was chemically treated with organic and inorganic reagents of which acetic acid augmented the sorption capacities for Reactive blue 19 and Reactive blue 49 attaining equilibrium in 60 min. While immobilisation of biosorbent into calcium alginate beads reduced the sorption capacity and the time to achieve equilibrium was prolonged up to 120 min. Sorption of both reactive dyes was found to be dependent on pH of media and maximum removal was observed at pH 2. The sorption process was fast and the data followed pseudo‐second‐order kinetic rate equation (R² = 0.99). The equilibrium data were also fitted to Freundlich, Langmuir and Temkin isotherms. The mechanism of sorption was found to be physiosorption. FTIR analysis and SEM imaging of biosorbent were also carried out to study functional groups involved and morphological changes at the surface of biomass. © 2011 Canadian Society for Chemical Engineering     

混合发酵法生产脐橙皮膳食纤维的研究

以绿色木霉和米根霉为发酵菌种,制备脐橙皮膳食纤维,以膳食纤维得率为参考指标,通过单因素及正交试验以优化最佳制备条件,结果表明:最佳制备条件为接种比例(绿色木霉∶米根霉)3∶2;发酵温度25℃;发酵pH值为6.5;发酵时间为3d.此时,所得的发酵产物中,SDF、IDF以及TDF得率分别为32.93％、49.87％、82.80％,持水力和溶胀性分别为6.12 g/g、15.29 mL/g.     

微波辅助提取香椿叶黄酮工艺的研究

比较微波辅助甲醇提取香椿黄酮与乙醇提取、甲醇回流和乙醇回流等工艺提取香椿黄酮的效果,用正交设计筛选微波辅助乙醇提取工艺条件,并探讨材料的液料比、体积分数、微波处理时间、微波功率对提取效果的影响,结果表明:微波辅助甲醇提取和乙醇提取效果明显优于其它传统方法;最佳工艺条件:液料比25 mL/g,乙醇体积分数70%,微波功率400 W,处理15 min。此工艺提取率达到70.15%,是一种高效、节能的提取香椿黄酮的工艺。     

辽宁省稻田养殖中华绒螯蟹中可食部分砷的含量特征及食用安全评价

目的 为了评价稻田养殖中华绒螯蟹体内砷的污染水平和膳食风险。方法 本研究中从辽宁省盘锦市和鞍山市采集了560份样本,采用电感耦合等离子体质谱仪和高效液相色谱-原子荧光法测定了肌肉、肝胰腺及性腺总砷和总无机砷（AsⅢ和AsⅤ）的含量,并利用目标危险商数（THQ）和致癌风险（CR）来评价对人体的健康风险。结果 中华绒螯蟹中总砷均值呈现雌蟹肝胰腺与性腺＞雄蟹肝胰腺与性腺＞雄蟹肌肉＞雌蟹肌肉的趋势,其中雄蟹肌肉与雌蟹肝胰腺及性腺总砷均值之间有显著性差异（P<0.05）,而雌蟹肌肉与肝胰腺及性腺总砷均值之间具有显著差异（P<0.05）;总无机砷均值呈现雌蟹肝胰腺与性腺＞雄蟹肝胰腺与性腺＞雌蟹肌肉＞雄蟹肌肉的趋势,总无机砷含量仅占总砷含量的5.014%-6.250%;盘锦市盘山县大洼区和胡家镇梁家村几个采样点的总砷和总无机砷含量相较于其他地区偏高,而其余的采样点总砷和总无机砷含量处在一个相对较低的水平;稻田养殖中华绒螯蟹所有样品的THQ值远低于1,CR值在10-6和10-4之间,经判别仅具有低致癌风险（level Ⅱ）。结论 稻田养殖中华绒螯蟹不会对消费者造成潜在的健康危害。     

Comparison of gas chromatographic volatile profiling methods for assessing the flavour quality of kenyan black teas

A comparison is made of the various ratios used to quantify black tea aroma such as: ratio of sum of gas chromatographic peak areas of compounds eluting before linalool (3,7-dimethyl-1,6-Octadien-3-ol) to those eluting after linalool (Wickremasinghe-Yamanishi ratio); gas chromatographic peak areas of compounds imparting sweet flowery aroma (Group II volatile flavour compounds) to those imparting green grassy aroma (Group I volatile flavour compounds), Owuor's flavour index; ratio of the sum of gas chromatographic peak area of the terpenoids to non-terpenoids, i.e. Mahanta ratio; and gas chromatographic peak area of linalool to E-2-hexena1, i.e. Yamanishi-Botheju ratio. The Wickremasinghe-Yamanishi ratio and Owuor's flavour index showed a significant relationship, the Mahanta ratio showed a significant but poor relationship, and the Yamanishi-Botheju ratio had no relationship with the tasters evaluation of Kenyan clonal CTC black teas. Similar results were obtained from orthodox black teas manufactured from different varieties.     

Characterization of Important Odorants in Steamed Male Chinese Mitten Crab (Eriocheir sinensis) using Gas Chromatography‐Mass Spectrometry‐Olfactometry

Chinese mitten crab (Eriocheir sinensis) from Yangcheng Lake in Jiangsu Province is a popular species due to its unique pleasant aroma and intensive umami taste. In this study, odorants in steamed male E. sinensis were investigated using the headspace‐monolithic material sorptive extraction technique coupled with gas chromatography‐mass spectrometry‐olfactometry (GC‐MS‐O). A total of 74 volatile compounds were found, and the results of the GC‐MS‐O analysis, combined with odor activity values, showed that trimethylamine (fishy, ammonia‐like odor), (Z)‐4‐heptenal (mushroom‐like odor), and benzaldehyde (paint‐like odor) were the important odorants (IOs) in all 4 of the edible parts of steamed male E. sinensis. Furthermore, heptanal (mushroom‐like odor) was common to the abdomen, claw, and leg meat but was not found as the IO in the gonad. The abdomen meat also contained 3‐methylbutanal (vegetable‐like, grassy odor), while 2 additional IOs were found in claw meat (2‐methylbutanal, which has a mushroom odor and 3‐ethyl‐2,5‐dimethylpyrazine, which has a chocolate‐like, musty odor). Another IO (2‐nonanone, chocolate‐like odor) was also found in leg meat, while (E)‐2‐nonenal (green, fruity odor) was the IO found exclusively in the gonad.     

Variations in the leaf standard,chemical composition and quality of black tea (Camellia sinensis) due to plucking intervals

Green leaf standard, chemical composition and quality of black tea (Camellia sinensis (L) O Kuntze) change with plucking intervals. Long plucking intervals lead to poor leaf standard with a lot of mature leaves and lower theaflavins, the sum of volatile flavour compounds imparting a sweet flowery aroma (group II volatile flavour compounds), caffeine contents and tasters' evaluations of black tea. The sum of volatile flavour compounds imparting inferior, grassy, green flavour (group I volatile flavour compounds) to tea, however, increases with long plucking intervals.