真空闪蒸制冰技术研究进展

冰浆作为一种性能优良的相变蓄冷材料广泛应用于生活及工业中,真空闪蒸制冰技术作为一种最具潜力的冰浆制备方法,有广泛的发展前景。介绍了真空闪蒸制冰的基本原理及物理过程,分别根据冰浆生成方式、真空维持系统设计方式对真空闪蒸制冰系统进行分类,详细分析了解决真空闪蒸制冰技术问题（维持真空度、强化传热、过冷）的研究,并对真空闪蒸制冰技术的进一步研究做出展望。     

Effect of Slurry Ice on the Functional Properties of Proteins Related to Quality Loss during Skipjack Tuna (Katsuwonus pelamis) Chilled Storage

The effect of slurry ice on the quality of Skipjack tuna (Katsuwonus pelamis) during chilling storage was investigated and compared to flake ice. Slurry ice‐treated samples showed significantly higher springiness and chewiness variables than the blank and flake ice‐treated samples (P < 0.05). The growth of microorganisms in tuna muscle treated with slurry ice was also down significantly (P < 0.05), and the total aerobic counts didn't reach higher scores than 5.0 log CFU/g during the whole chilling storage. Additionally, the myofibrillar protein, Ca²⁺‐ATPase activity, and total sulfydryl (SH) content in muscle treated with slurry ice were all significantly higher than the blank and flake‐iced samples (P < 0.05). This was probably due to the faster cooling, subzero final‐temperature, and larger heat exchange derived from slurry ice. Standard error of mean and sodium dodecyl sulfate–polyacrylamide gel electrophoresis results also confirmed that slurry ice treatment could effectively retard the degradation of myofibrillar proteins and showed a positive effect on the stability of tissue structures.     

COMPARISON STUDY OF EGG YOLKS AND EGG ALTERNATIVES IN FRENCH VANILLA ICE CREAM

Egg alternatives may replace egg as a functional ingredient in French vanilla ice cream due to their functional and dietary benefits. These egg alternative ingredients include modified corn starch (MCS), whey protein concentrate (WPC) and soy protein isolate (SPI). The objective of this study was to compare the physical and sensory properties of several commercially available egg alternatives in a vanilla ice cream formulation. The SPI exhibited a significantly lower L value compared with the other egg alternatives, whereas the control exhibited a significantly higher b value compared with the other treatments. The apparent viscosity value of MCS was approximately 10-fold greater than the other egg alternatives. There were no significant differences in appearance and mouth-feel among the control, MCS or WPC treatments, whereas SPI exhibited a significantly lower mouth-feel score compared with the other treatments. The control exhibited significantly higher flavor and acceptability scores compared with the other egg alternatives, whereas SPI treatment exhibited least desirable flavor and acceptability. Consumer panelists would purchase the control with the egg alternative formulations.

PRACTICAL APPLICATIONS

The egg alternatives were used to replace egg as a functional ingredient in French vanilla ice cream production. These alternatives can deliver functionality at a lower cost and can be incorporated to produce a suitable ice cream.     

精炼脱臭中冷冻水真空系统和乙二醇型“干冰”冷凝真空系统的技术经济分析

介绍了冷冻水真空系统和乙二醇型"干冰"冷凝真空系统的工作原理及工艺特点,并进行了技术性能对比。对两种真空系统应用在不同规模精炼脱臭生产线的经济效益进行了对比,分析了两者的适用范围。结果表明:冷冻水真空系统更适用于中、小规模油脂精炼脱臭真空系统,乙二醇型"干冰"冷凝真空系统更适用于大、中规模油脂精炼脱臭真空系统。     

冷冻浓缩过程中制冷面的冰淤塞的检测与表征（11）

根据冰淤塞的机理和对本文第一部分（I）所述的冰晶在过冷金属表面上的冰淤塞的启动时间和诱导时间的实验数据的分析,建立了关联冰淤塞诱导时间与制冷面壁温和晶种用等因素的关系的数学模型。文中还对影响冰淤塞的各因素做了研究分析。     

黄河内蒙古段冰盖厚度模拟

基于原型观测数据对黄河内蒙古段的冰盖厚度进行模拟,通过引入Colburn类比法计算冰盖下的热通量,在热力学方程中引入河流流量、水流流速、水位河道坡降、冰盖糙率等因素,改进基于Stefan公式的度日法冰厚计算模型。采用巴彦高勒至头道拐河段4个测站的原型观测数据率定该冰厚计算模型的相关参数,并通过气温、水温数据进行冰厚计算。结果表明：改进后的冰厚计算模型在计算结果的精度上达到1.97％,相比于Stefan模型的14.99％、统一度日法模型的4.77％、动水冰厚辐射冰冻度日法模型的14.98％,精度上有所提升,冰厚变化趋势与现场原型观测趋势一致;根据累积气温值与气温序列特征分析2006—2017年的头道拐测站气温数据,提取冬季累积气温值最大的2009—2010年进行冰厚计算,模型计算结果精度为734％。[JP]改进模型在正常天气条件和极端天气条件下的冰厚计算结果均保持较高的精度,研究结果可为极端天气条件下研究区的冰厚计算提供理论依据。     

滩、浅海固定设施冰载荷的研究

随着我国浅海地区石油勘探与开发的蓬勃发展,滩、浅海固定设施在海冰环境中的安全日益突出,对这些地区海冰环境特别是冰的特性参数和冰对结构作用力的研究迫在眉睫。本文在研究和分析国内外冰力计算公式的基础上,给出了一个单桩平整冰的冰力计算公式,该公式物理意义明确,考虑了影响冰力的主要因素,是目前全面反映冰对结构物作用的一个冰力计算公式,它同时与现行规范标准上推荐的公式接近,工程上容易接受,且其计算结果最接近于冰力计算的统计平均值。     

静冰压力对铰链式护坡系统作用的低温模型试验

通过低温模型试验模拟了冰盖的形成过程,测试了静冰压力、铰接块位移、冰盖厚度、温度等,建立了这些物理量与时间的关系。根据静冰压力的发展过程、变化原因评价了试验与自然环境的相似性。根据铰链式护坡系统在静冰压力作用下沿坡面位移变形和冰盖融化后的残余变形,评价了该护坡系统的稳定性以及该护坡系统作为柔性护岸结构适应变形的能力,分析了静冰压力、铰接块位移的发生、发展、消失过程和变化原因。试验结果表明:静冰压力作用下铰链式护坡系统沿坡面位移变形很小,冰盖融化后该护坡系统的残余变形也很小;铰链式护坡系统在静冰压力发生、发展和消失的过程中,能够适应岸基变形而不被破坏。     

中国北方寒冷地区河冰灾害调查与分析

根据调查收集的北方寒冷地区的气象资料和河流的冰情资料,对这些地区的气温分布及主要河流冰情的发生、演变过程进行了统计与分析。描述了北方河冰灾害的几种主要形式,论述了目前国内外冰情研究的方法和成果,为我国已建和在建输水工程的安全运行提供参考。     

基于网络的自适应模糊推理系统在冰情预报中的应用

本研究将基于网络的自适应模糊推理系统应用在冰情预报中。通过分析基于网络的自适应模糊推理系统的网络结构、水温数据及其相关预报因子的分布特点、隶属度函数个数及预见期对预报结果影响的比较,确定了隶属度函数类型、隶属度函数个数和预报的预见期。文中以黄河宁蒙河段石嘴山为例,介绍水温预报的应用研究,并将预报水温同实测水温进行比较。通过描述预报值和实测值关系的确定性系数,对预报结果作了分析。结果表明,除了石嘴山水文站2002年预报结果实测值和预报值偏差较大、确定性系数偏小之外,其余预报组次中预报值和实测值均吻合较好,达到甲等预报方案。