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提出一种低能耗膜蒸馏与溶液除湿集成型干燥装置,通过除湿干燥单元将物料中的水分转移到除湿溶液中,再通过除湿溶液再生单元将除湿溶液吸收的水分分离排出;给出了装置除湿能耗比(SMER)的估算公式,在典型工况参数下装置的SMER可达6.36kg/(kW·h);以表面经过亲水化处理的热敏性棉纤维为被干燥物料,以质量分数50%的LiBr水溶液为除湿溶液进行除湿干燥单元试验装置研究,实现了物料中水分向除湿溶液中转移,且试验装置具有自稳定和能量自平衡等特性;研制了基于中空纤维束—套管型气隙式膜蒸馏组件的除湿溶液再生试验装置,实现了对质量分数50%的LiBr水溶液的浓缩再生,且再生过程具有很高的分离效率。 相似文献
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山药片阶段降湿促干特性及多物理场耦合模型 总被引:2,自引:0,他引:2
目的:探明热风干燥过程中阶段降湿调控策略对农产品物料干燥特性的影响。方法:研究了60℃干燥条件下,恒湿干燥(相对湿度15%,25%,35%,45%)和阶段降湿干燥(第一阶段相对湿度45%保持10,20,30,60 min,第二阶段相对湿度15%)对山药片的干燥特性的影响,构建热质传递多物理场耦合模型进行验证,并测定干燥后产品的复水比和微观结构变化。结果:①恒湿干燥时,干燥速率随相对湿度的增加而降低;但阶段降湿干燥(50%相对湿度保持15 min而后降为20%)的干燥时间比恒湿干燥(相对湿度20%)的缩短了14.3%。②山药片干燥速率总体呈先升速后降速的趋势,水分有效扩散系数Deff变化范围为7.16×10-10~2.34×10-9 m2/s;多物理场耦合模型拟合结果表明,相对湿度越高,物料升温速率越快,内部水分向外扩散迁移速度也越快。③复水比随着相对湿度的升高呈先升高后降低趋势;阶段降湿(相对湿度50%保持15 min而后降为20%)干燥时,山药片内部呈蜂窝状的多孔结构,有利于内部水分向外迁移,此条件下复水比最高为6.85±0.05;而恒湿干燥(相对湿度为20%)时,山药片内部水分扩散通道发生收缩坍塌、结壳堵塞,复水率较低。结论:热风干燥时,阶段降湿调控策略可显著缩短干燥时间,并有效改善物料微观结构,提高产品复水率;构建的多物理场耦合模型能够准确模拟阶段降湿干燥过程中山药片内部的热质传递过程。 相似文献
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研究雪莲果样品厚度、装料量、干燥温度、风速和旁通比对雪莲果热泵干燥特性及质量变化的影响。结果表明:雪莲果干燥速率随着样品厚度和装料量的增加而降低,随着干燥温度和风速的升高而增加。雪莲果热泵干燥过程绝大部分以降速干燥为主伴随相对较短时间的恒速干燥,而有些干燥速率曲线只存在降速干燥阶段。综合考虑单位能耗除湿率、色泽差异、收缩率、复水比,雪莲果热泵干燥最适参数范围:样品厚度2~4 mm、装料量1~2 kg/m2、干燥温度25~35℃、风速1.5~2.0 m/s。而旁通比对雪莲果热泵干燥进程影响不显著。 相似文献
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为探讨铁棍山药超声强化热泵干燥的水分迁移规律,对山药进行直触超声强化热泵干燥试验,研究超声功率对干燥特性及水分变化的影响。结果表明:在热泵干燥过程中施加超声有利于加快脱水进程。随着超声功率从0 W提高至60 W,干燥时间从630 min缩短至390 min,平均干燥速率由0.0053 g/(g·min)提高到0.0086 g/(g·min),有效水分扩散系数由0.887×10-10 m2/s,增大至1.393×10-10 m2/s。扫描电镜结果表明:施加超声使物料组织结构变疏松,产生微孔道。随着超声功率的提高,微孔道数量变多,孔隙率变大。低场核磁共振分析表明:铁棍山药中存在自由水、不易流动水和结合水3种状态水,且在干燥过程中其内部水分能够相互转化。自由水的含量不断降低,直至被完全去除;不易流动水的含量在干燥过程中先增高后降低,在干燥结束时仍存在部分不易流动水;结合水的含量在超声强化热泵干燥过程中几乎不变。铁棍山药的核磁共振成像显示,在干燥过程中,物料水分从外到内逐渐流失。提高超声功率能有效加快物料内部水分迁移,促进水分的去除。本研究结果可为果蔬超声强化热泵干燥技术的研发与应用提供参考。 相似文献
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<正>一、前 言 干燥是食品工业生产中利用热能除去固态物料中水分或其它溶剂的单元操作。一般食品为便于贮存,运输,加工或应用, 在保持原物料营养成分不变的前提下,常用干燥方式进行脱水。干燥是物料中水分向外转移的过程。在这个过程中,理论上讲只要物料的水蒸汽分压力大于周围环境(或干燥设备容器内)的水蒸汽分压力,水分就会不断的向外扩散。因此,在干燥过程中要不断地排除湿汽以保持有一定水蒸汽分压力差;此外为增加物料中水分子向外扩散的能力,常需对物料施加一些能量——热能。水分子吸收热能后,成为自身蒸发的汽化潜热,增加物料脱水的速率。 相似文献
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利用自主研发的搅拌式-热泵穿流干燥仓,研究了新鲜稻谷的脱水过程.考察了热泵干燥条件对稻谷干燥品质和过程性能的影响.结果表明,稻谷热泵干燥一直处于降速干燥阶段;当热泵干燥温度为35℃时,干燥仓可用7.5h将300kg稻谷从25%的初始含水率降至14%,过程单位能耗为2022kJ/kg water,爆腰增率为1.3%.通过与热风干燥、自然晒干过程比较发现,较之自然晒干,热泵干燥可以大幅度缩短干燥时间,阻止稻谷发霉;较之热风干燥,温和的热泵干燥可以获得较低的爆腰增率,单位能耗低.该结论可以为基于热泵干燥技术的循环式干燥机以及间歇式大型干燥机械的开发提供依据. 相似文献
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常用消毒灭菌法及其机理与应用 总被引:3,自引:0,他引:3
介绍了采用消毒灭菌方法,有加热消毒法,紫外线辐射法和化学药剂消毒法。常用化学药剂有醛类、含氯消毒剂、醇类消毒剂以及高锰酸钾、生石灰等,阐释了消毒与灭菌两个概念的区别。 相似文献
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Figueroa-González I Quijano G Ramírez G Cruz-Guerrero A 《Journal of the science of food and agriculture》2011,91(8):1341-1348
Owing to their health benefits, probiotics and prebiotics are nowadays widely used in yogurts and fermented milks, which are leader products of functional foods worldwide. The world market for functional foods has grown rapidly in the last three decades, with an estimated size in 2003 of ca US$ 33 billion, while the European market estimation exceeded US$ 2 billion in the same year. However, the production of probiotics and prebiotics at industrial scale faces several challenges, including the search for economical and abundant raw materials for prebiotic production, the low-cost production of probiotics and the improvement of probiotic viability after storage or during the manufacturing process of the functional food. In this review, functional foods based on probiotics and prebiotics are introduced as a key biotechnological field with tremendous potential for innovation. A concise state of the art addressing the fundamentals and challenges for the development of new probiotic- and prebiotic-based foods is presented, the niches for future research being clearly identified and discussed. 相似文献
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Wim Verbeke Federico J.A. Pérez-Cueto Marcia D. de Barcellos Athanasios Krystallis Klaus G. Grunert 《Meat science》2010
This paper presents the combined mid-term findings of the consumer research components of two EU Sixth Framework Programme integrated projects concerning meat, ProSafeBeef and Q-PorkChains. The consumer pillar of ProSafeBeef carried out eight focus group discussions in May 2008, in France, Germany, Spain and the UK. Q-PorkChains conducted a large-scale, web-based, consumer survey in January 2008 in Belgium, Denmark, Germany, Greece and Poland. The first project provides a set of qualitative data from a small cohort of focus groups and the second a set of quantitative data from a larger consumer sample. This paper draws together the main findings of both projects and provides a comprehensive overview of European citizens’ and consumers’ attitudes towards and preferences regarding beef and pork. In general, consumers consider meat to be a healthy and important component of the diet. Consumers support the development of technologies that can improve the health attributes of meat products and guarantee eating quality, but they have a negative view of what they see to be excessive manipulation and lack of naturalness in the production and processing of beef products. In the Q-PorkChains study consumer and citizen segments are identified and profiled. Consumer segments were built upon the frequency and variety of pork consumption. The citizen segments were built upon their attitudes towards pig production systems. Overall, the relationship between individuals’ views as citizens and their behaviour as consumers was found to be quite weak and did not appear to greatly or systematically influence meat-buying habits. Future studies in both projects will concentrate on consumers’ acceptance of innovative meat product concepts and products, with the aim of boosting consumer trust and invigorating the European beef and pork industries. 相似文献
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果蔬可以提供营养, 有利于人类健康, 而果蔬的后熟及其与环境的相互作用会影响果蔬采后的质量和安全。对果蔬生物学过程的了解和掌握是减少果蔬采后损失和保障果蔬采后质量和安全的关键。在过去的10多年, 基于组学技术的系统生物学在了解果蔬后熟及其与环境相互作用的分子机制方面得到了越来越多的应用。本文对此做了细致的总结, 指出了存在的不足, 并提出了未来的发展方向。 相似文献
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The objectives of the current study were to investigate the relationship between body condition score (BCS) and dairy form and changes in genetic parameters for BCS and dairy form within and across lactations and age. Body condition score and dairy form were obtained from the Holstein Association USA, Inc. Records were edited to include those cows classified between 24 and 60 mo of age and between 0 and 335 d in milk (DIM). A minimum of 20 daughters per sire and 15 cows per herd-classification visit were required. The dataset consisted of 135,178 records from 119,215 cows. Repeatability, multiple trait, and random regression models were used to analyze the data. All models included fixed effects for herd-classification visit, age within lactations 1, 2, and 3 or higher, and 5th-order polynomials for DIM. Random effects included sire and permanent environment for all models. Random regression models included age at classification nested within sire or DIM and lactation number nested within sire. Genetic variance for both BCS and dairy form was lowest in early lactation and highest in midlactation. Genetic correlations within and across lactations were high. The genetic correlation between DIM 0 in lactation 1 and DIM 305 in lactation 3 was estimated to be 0.77 for BCS and 0.60 for dairy form. The genetic correlation estimate between 30 mo of age at classification and 50 mo of age at classification was 0.94 for both dairy form and BCS. The repeatability models appeared to generate accurate evaluations for BCS or dairy form at all ages and stages of lactation. 相似文献
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酚类物质的结构与性质及其与葡萄及葡萄酒的关系 总被引:20,自引:0,他引:20
酚类物质是一类大而复杂的化合物。葡萄与葡萄酒中常见的酚类物质可分为类黄酮和非类黄酮两大类,它们是葡萄中重要的次生代谢产物,与葡萄的抗病性、采后生理、贮存、保鲜等密切相关。葡萄酒中的酚类物质来自于葡萄果实、果梗、酵母代谢以及橡木桶,参与形成葡萄酒的味道、骨架、结构和颜色等,对红葡萄酒的特征和质量尤其重要。 相似文献