3种抗氧化剂对辐照猪肉火腿肠异味的控制技术研究

为探讨即食肉制品辐照过程中异味形成的有效控制措施,本研究选取VE、茶多酚、迷迭香提取物3种抗氧化剂,在火腿肠加工过程中添加到肉糜中,研究其对火腿肠辐照异味强度的影响,并筛选出控制火腿肠辐照异味最好的抗氧化剂,进行响应面优化试验,分析火腿肠的储藏效果和辐照异味的调控工艺。结果表明,3种抗氧化剂中迷迭香提取物对火腿肠辐照异味的控制效果最好。火腿肠异味控制的最优条件为:迷迭香提取物浓度0.55%、辐照剂量5.733 kGy、储藏温度4℃。贮藏7 d后火腿肠中总菌落数为1.253 log(CFU·g^-1),与对照组样品相比,菌落总数降低了83%,辐照异味感官评价值为4.30,几乎无辐照异味。本研究为辐照技术在即食肉制品保鲜方面的应用提供了数据支撑。     

蔬菜废弃物与畜禽粪便联合好氧发酵挥发性有机物排放特征

为研究蔬菜废弃物与畜禽粪便联合好氧发酵过程产生的挥发性有机物(volatile organic compound,VOCs)及主要致臭物质,开展了蔬菜废弃物与畜禽粪便联合好氧发酵试验,采用气相色谱-质谱法和三点比较式臭袋法分析了好氧发酵升温、高温和降温阶段产生的VOCs种类和浓度及臭气浓度。结果表明,蔬菜废弃物与畜禽粪便联合好氧发酵过程共检出34种VOCs,其中芳香烃类化合物11种、烷烃7种、含硫化合物4种、酮类4种、卤烃类化合物3种、醇类2种、酯类2种、醛类1种;发酵升温期臭气浓度最大,达72 443,而在降温期产生的VOCs种类最多为29;在联合好氧发酵过程中主要致臭物质为甲硫醚、二甲二硫醚、二硫化碳、NH3和H2S,羰基硫、乙醛和苯乙烯仅在高温期产生且浓度较高;根据嗅阈值比值大小与最大浓度,需重点监测和控制恶臭物质的顺序是二甲二硫醚H2SNH3甲硫醚。该研究结果为蔬菜废弃物与畜禽粪便联合好氧发酵过程中恶臭物质的监测和控制策略研究提供理论依据。     

Analysis of the Mechanical Behavior of Gusset Plate to CHS KK joints

A nonlinear finite elements analysis was carried out to investigate the failure modes and the ultimate strength of gusset plate to CHS KK joints. The effects of web loading proportion, geometric parameters and axial stress in chord on the ultimate strength were considered. It was found that the ultimate strength of gusset plate to CHS KK joints was greatly decreased with the increase of web loading proportion when the proportion value was positive; however, the web loading proportion had less effect on the ultimate strength when the proportion value was negative. And with the varying of web loading proportion, the effect of the axial stress in chord on the ultimate strength of KK joints had a complex effect on the joint mechanic behavior. Based on the regression analysis, a formula was proposed for predicting the ultimate strength of gusset plate to CHS KK joints.     

Effect of space velocity on the performance of methane steam reforming in a plate micro channel reactor

A 2 D numerical simulation is conducted on the steam reforming reaction in a plate micro reactor by applying the general finite reaction rate model in the CFD software FLUENT and a detailed surface reaction kinetics mechanism. Catalyst space velocity(CSV) and gas space velocity(GSV) inlet mixture impact on the reaction is discussed. During the calculations, the space reaction effect is ignored and only the reaction of CH4 on catalytic surface is taken into account. Calculation results show that lower CSV or GSV can achieve high efficiency conversion of CH4 and H2 output; besides CSV and GSV, channel height is an important factor for the reforming performance of plate micro reactors.     

基于HPLC法的向日葵盘中绿原酸含量测定

［目的］采用HPLC法测定向日葵盘绿原酸的含量。［方法］采用高效液相色谱法。其中,色谱柱为Hypersil ODS（4.6 mm×200 mm,5 μm）,甲醇-冰醋酸-乙腈（18∶35∶2）为流动相,流速为1.0 ml/min,检测波长为327 nm。［结果］绿原酸在3.24～89.21 μg/ml范围内线性关系良好,回归方程为：C=23.63A-3.98,r=0．999 8,平均回收率为98.12％,RSD=0.27％。［结论］所建方法准确可靠,操作简便,稳定性好,可用于绿原酸生产的质量控制。     

低速回流风洞烟流显示技术的研究

通过对两种不同模型烟流显示技术的研究，得出在低速回流风洞内进行烟流显示试验的一些重要结论。风洞试验结果表明，无论从照片，录相片或幻灯片上观察，该显示技术都已达到国内、国际水平。     

耐低温草菇菌株的覆层平板法筛选

采用分割切块法测定了3个草菇菌株(V01、V02和V03)在低温下的致死时间。结果表明：V01、V02和V03菌株在0、2和4℃下的致死时间分别为24、48和32h，48、88和64h，96、192和144h。用0．01％吖啶橙诱变草菇菌株V01担孢子30min，致死率达70．4％；对诱变处理的担孢子萌发形成的菌体进行低温临界致死处理，杀死低温敏感菌株，采用覆层平板法筛选出4株耐低温的草菇菌株。     

玉米育苗营养钵形状和容积对育苗效果的影响

对玉米和黄瓜根系的生长特性进行了比较,确定了有利于玉米秧苗根系生长的钵体形状——上小下大的圆台形,通过试验确定了能够满足玉米秧苗生长农艺要求的营养钵的容积;根据我国农村的实际情况,设计了价格低廉,适用性好的可降解的纸质育苗盘,解决了育苗过程中的窜根和根坨易变形的问题。     

粪肠球菌生长曲线的测定

用分光光度仪和活菌计数两种不同的方法对粪肠球菌生长曲线进行测定,结果表明,在细菌对数生长期以前,两种方法所得结果基本一致,但在衰亡期,两种方法具有差异,活菌记数法更能如实反映细菌的生长情况.     

Testing garlic cloves and bulblets for onion yellow dwarf virus by ACP-ELISA

Onion yellow dwarf virus (OYDV) was detected in cloves and aerial bulblets of garlic (Allium sativum) at levels as high as or higher than in leaves of plants grown from tested cloves. It is recommended to test bulblets or a few cloves per bulb before planting to determine if all cloves of a bulb are virus-free. This aids in early detection and allows a more thorough testing of stock than field testing.