An Improved Process for Retort Cooking Atlantic Blue Crab

Abstract

Non-uniform steam distribution and large temperature differences are frequently found within the retort during pressure steam cooking of blue crabs. A precook treatment involving evacuation of air from the retort prior to introduction of steam was found to decrease this unevenness in temperature distribution. The conventional and modified treatments were compared by (1) determination of temperature profiles within a retort during the conventional cooking process and the modified process; and (2) testing the resulting product from the two processing methods for differences in meat moisture and pH. The modified process improved the temperature distribution and reduced cook time by up to 50%. Meat moisture content increased in crabs processed using the vacuum process while pH testing of the cooked meat showed little difference in meat from the two processes. It was concluded that the improved temperature distribution would shorten cook time and increase throughput, product yield, product safety, and process efficiency.     

Comparison of Phosphorus Determination Methods by Ion Chromatography and Molybdenum Blue Methods

The suppressed ion chromatography (IC) and molybdenum blue methods were used to comparatively evaluate phosphorus (P) concentrations. Most of the P was more resistant to hydrolysis in ion chromatography as compared to the molybdenum blue method. However, P analysis by IC is more liable to be interfered than the molybdenum blue method because of the presence of high bivalent and trivalent metal ions. Polyvalent metal ions interfere with organic P hydrolysis or the release of P from colloids during P investigation, which leads to a difference of ortho-phosphate concentrations determined by IC and molybdenum blue methods. During the environmental samples analysis, the ortho-phosphate obtained by the IC method was usually less than that obtained by the molybdenum blue method.     

基于识别技术的岩羊步态分析

岩羊善于攀岩跳跃,岩羊的运动步态变化规律是研究仿生四足机器人运动机理的基础。本文从仿生学的角度出发,以岩羊为试验对象,建立岩羊三维步态试验系统,运用VFW方法进行岩羊运动视频的采集,并运用专业图像处理软件Sigma Scan进行图像处理,最终得到岩羊四肢关键点的位置、加速度曲线。试验获得完整的岩羊步态信息及分析结果,可...     

不同锌源对蓝狐生长及肝脏中锌铁含量的影响

为了考察在日粮中添加有机锌和无机锌对于蓝狐生长及肝脏中锌铁含量的影响。选取60日龄断乳蓝狐90只,于2007年8月2日~12月27日进行饲养试验。结果表明:在日粮中添加不同锌源的添加剂对于蓝狐生长及肝脏中锌铁含量的影响是不同的。与无机锌组比较,有机锌低剂量组和有机锌高剂量组在整个试验期的平均日增重分别提高了9.62%和12.67%,而且均差异显著(P<0.05);有机锌低剂量组与有机锌高剂量组之间的差异不显著(P>0.05)。有机锌低剂量组和有机锌高剂量组的肝脏中的锌含量比无机锌组分别提高了4.23%、15.15%,其中有机锌高剂量组极显著高于其他试验组(P<0.01),无机锌组与有机锌低剂量组的差异不显著(P>0.05)。有机锌低剂量组和有机锌高剂量组肝脏中铁的含量虽都比无机锌组略有提高,但差异均不显著(P>0.05)。     

海洋之风——心灵的回归

现代流行的海洋风格引导了装饰界新的一股潮流,蓝色调的简约装饰带给了居住者前所未有的宁静,带来一丝清凉、自然的韵味,强调了一种视觉上的冲击力。     

酸性茜素兰褪色光度法测定食盐中碘含量

[目的]介绍加碘盐中碘含量测定的新方法。[方法]根据碘酸银氧化酸性茜素兰使其褪色,且褪色前后溶液的吸光度差ΔA与碘含量成正比的原理,在最佳褪色条件下测定食盐样品A、B中的碘含量 在样品液中加入碘酸钾标准溶液,测定碘的回收率。[结果]酸性茜素兰在517 nm处有最大吸光度,其最佳褪色条件为温度40℃,时间10 min,0.5 mol/L溴化钾用量4.00 ml,硫酸用量2.00 ml,0.50 g/L酸性茜素兰用量5.0 ml 10.029 0 g样品A和10.030 2 g样品B中碘的含量分别为26.52和32.83 mg 样品液A、B中碘的加样回收率分别为95.0%和104.2%。[结论]酸性茜素兰褪色光度法测定食盐中的碘含量具有稳定性好,准确度、灵敏度高,操作简便等优点,具有推广应用价值。     

Quantifying current and future risks of invasiveness of non-native aquatic species in highly urbanised estuarine ecosystems—A case study of the River Neretva Estuary (Eastern Adriatic Sea: Croatia and Bosnia–Herzegovina)

Biological invasions are a major driver of global environmental change as invasive non-native species can exert severe environmental impacts on invaded ecosystems. Estuaries are especially vulnerable to biological invasions, which in highly urbanised areas are further facilitated by introduction pathways linked to commercial activities. This study provides a risk screening of non-native invasive species for the highly urbanised River Neretva Estuary (Eastern Adriatic Sea: Croatia and Bosnia–Herzegovina). In total, 12 species of non-native aquatic organisms were identified and screened for their invasiveness with the Aquatic Species Invasiveness Screening Kit. Of these species, eight were classified as carrying a high risk of invasiveness under current climate conditions and nine under future climate conditions. Amongst the high-risk species, blue crab Callinectes sapidus has already caused impacts in the risk assessment area, where it also represents an important economic resource. The “horizon” species Pacific oyster Crassostrea gigas and Manila clam Ruditapes philippinarum also carried a high risk of invasiveness, which for the latter species applied under predicted global warming. The present findings will contribute towards preventative management and control measures for the conservation of the natural ecosystem of the River Neretva Estuary whilst accounting for aquatic farming demands.     

空气湿度对蓝果忍冬相对生长和外部形态的影响

以蓝果忍冬5个种(“阿尔泰忍冬”、“勘察加忍冬”、“巴利斯忍冬”、“蓝靛果忍冬”、“博奇卡勒尼卡娃忍冬”)和1个品种(“EYL-1”)的2 a生扦插苗为试材,研究不同空气湿度处理对蓝果忍冬株高、相对生长量和外部形态的影响,以期为蓝果忍冬的驯化栽培提供理论依据.结果表明:空气湿度不仅影响蓝果忍冬的生长发育,而且对外部形态也有显著影响.在RH 75％处理下,蓝果忍冬生长良好,随着空气湿度的下降,植株株高及相对生长量呈下降趋势,“勘察加忍冬”在各相对湿度处理下的相对生长量均是最小.在RH45％处理20 d后,“勘察加忍冬”、“博奇卡勒尼卡娃忍冬”、“蓝靛果忍冬”叶片部分出现萎蔫、下垂、失去光泽、甚至脱落,而“阿尔泰忍冬”在低空气湿度下表现良好,可作为优良育种材料.