渗透蒸馏及其在食品工业中的应用

对渗透蒸馏过程、渗透蒸馏的特点及渗透蒸馏在食品工业中的应用作以综述     

渗透蒸馏及其在食品工业中的应用

对渗透蒸馏过程、渗透蒸馏的特点及渗透蒸馏在食品工业中的应用作以综述      

果汁浓缩技术概述

介绍了果汁浓缩技术的发展现状,包括真空蒸发技术、冷冻浓缩技术、膜技术在果汁浓缩过程中的应用,以及各浓缩技术的研究的现状;膜技术中,重点介绍了渗透蒸馏、膜蒸馏及集成膜技术的发展现状;比较了各浓缩技术的优缺点。从果汁市场的扩大和产品质量要求的角度指出了膜技术在果汁行业中的应用前景。     

几种膜分离技术在果汁浓缩中的应用

果汁浓缩通常采用的是多级真空蒸发法或冷冻法，这些方法由于热导致果汁芳香成分的大量损失，色泽分解和“煮熟味”的产生，不仅消耗大量的能源，而且生产成本高。膜分离技术具有节约能源、降低损耗、可在常温下连续操作、过程简单、高效、没有相变、分离系数较大等优点，其特别实用于热敏性物质的处理，在食品加工、医药、生化技术领域有独特的实用性。本论述了超滤技术、纳滤技术、渗透蒸溜技术以及集成膜分离浓缩技术在果汁加工中的最近应用研究现状，阐明了各自的特点和现存的技术难题，揭示了膜技术的广阔应用前景。     

油脂下脚中甾醇蒸馏浓缩

<正> 1.前言动物油中的胆甾醇,植物油中的谷甾醇、豆甾醇和菜油甾醇,已成为当今甾体药物生产的主要原料,甾醇及其衍生物作为高级化妆品生产的乳化剂或特种基剂也已进入工业应用。谷甾醇和豆甾醇还以其独特的消炎、退热及抗肿瘤等功能用作临床医药,也早就载入多国药典。谷甾醇在纺织柔软剂、磨木纸浆光稳定剂、汽油乳化剂、颜料分散剂、鱼虾等动物生长促进剂、家蚕人工饲料添加剂、航天食品添加剂等多方面开拓应用也展显出良好前景。油脂中普遍含有甾醇。油脂中甾醇在     

果汁冷冻浓缩过程中冰晶形成规律的研究

本研究测定了橙汁和菠萝汁的冰点曲线,并以此探讨在果汁冷冻浓缩时水分冻结率的变化规律。结果表明,果汁在开始冻结的温度附近结冰率变化最大;以后逐渐减慢。橙汁和菠萝汁的最大冰晶生成区分别是-0.8～-7.9℃和-0.7～-6.7℃。冷却介质温度越低,冰晶的生长速度越快,但最终冰晶尺寸越小。当介质温度为-10℃左右时,可获得较大的冰晶尺寸。本文也研究了搅拌作用及果汁预处理因素对冰晶生长的影响。     

荔枝果汁冷冻浓缩结晶速率的研究

研究荔枝果汁冷冻浓缩过程中冷媒温度、果汁可溶性固形物含量对冰晶尺寸大小和冰晶生长速率的影响,以及溶液主体的搅拌速度及溶液的黏度对冰晶生长速率的影响.结果表明:冷冻浓缩初期,果汁冰晶尺寸增长速率较大,是控制果汁冰晶尺寸的关键阶段;冷媒温度越低、可溶性固形物含量越高,冰晶的生长速率越快,但冷媒温度越低,冰晶的最大尺寸越小;果汁主体的搅拌速度越大、果汁主体黏度越低,果汁冰晶生长速率越快.     

超高压(UHP)技术在果汁灭菌中的应用

超高压处理技术被认为食品非热杀菌技术中最有潜力和发展前途的一种处理技术。我国的食品工业发展计划中超高压杀菌技术已经被列为重点开发的技术之一,超高压前几年一直处在小型试验研究阶段,如李里特与日本国际农林水产业研究中心的辰巳英三合作,对超高压下生产的豆腐凝胶进行了多方面的研究。     

果汁原浆中葡萄糖含量测定的酶电极设计

利用易于制备的水不溶性普鲁士蓝制备了介体掺入式丝网印刷电极,并以该电极作为电化学换能器制备葡萄糖氧化酶电极。电化学表征结果显示,酶电极对葡萄糖的电流响应特征良好,其线性范围为8.0 μmol/L～2.2 mmol/L,检测限达0.082 7 μmol/L（RSN=3）,灵敏度为1.016 μA·L/mmol,响应时间5 s,其抗干扰性能、稳定性及重复性良好。实验还确定了该酶电极的最佳制备配方及工作条件。该电极制作简单、廉价,适用于成分复杂的果汁原浆的快速分析测试。     

Potential of Membrane Distillation for Production of High Quality Fruit Juice Concentrate

Fruit juices are generally concentrated in order to improve the stability during storage and to reduce handling, packaging, and transportation costs. Thermal evaporation is the most widely used technique in industrial fruit juice concentrate production. In addition to high energy consumption, a large part of the characteristics determining the quality of the fresh juice including aroma, color, vitamins, and antioxidants undergoes remarkable alterations through the use of high operation temperatures. Increasing consumer demand for minimally or naturally processed stable products able to retain as much possible the uniqueness of the fresh fruit has engendered a growing interest for development of nonthermal approaches for fruit juice concentration. Among them, membrane distillation (MD) and its variants have attracted much attention for allowing very high concentrations to be reached under atmospheric pressure and temperatures near ambient temperature. This review will provide an overview of the current status and recent developments in the use of MD for concentration of fruit juices. In addition to the most basic concepts of MD variants, crucial suggestions for membrane selection and operating parameters will be presented. Challenges and future trends for industrial adaptation taking into account the possibility of integrating MD with other existing processes will be discussed.     

Potentialities of High-Pressure Homogenization to Inactivate Zygosaccharomyces bailii in Fruit Juices

ABSTRACT: This experimental work was aimed to evaluate the effects of repeated high-pressure homogenization (HPH) treatments at 100 MPa on the inactivation and regrowth of Zygosaccharomyces bailii inoculated in apricot and carrot juices. Thus, the spoilage yeast was inoculated in both the juices at level of about 5 log CFU/g and the 2 systems were treated with a lab-scale Panda homogenizer for 8 passes at 100 MPa. Microbiological and chemico-physical analyses were performed immediately after the treatment and during the juice storage at room temperature. Microbial data highlighted that yeast inactivation increased with the number of passes applied. Eight passes at 100 MPa allowed yeast inactivation higher than 2.5 log CFU/mL regardless of the juice considered. On the contrary, the juice type affected the yeast fate (growth or death) over the storage at 25 °C. In fact, Z. bailii was able to attain the spoilage threshold (6 log CFU/mL) in apricot juice, although with growth kinetics dependent of the survivor levels after HPH treatment. In carrot juice this microorganism was unable to recover over the storage in the most severely treated samples. The HPH treatment had a significant effect on apricot juice pH and viscosity, while no significant effect was observed in carrot juice. The viscosity measurements showed that the application of one pass at 100 MPa resulted in the triplication of apricot viscosity index. No further significant viscosity increase (P > 0.05) was observed increasing the number of passes at 100 MPa. Practical Application: The results obtained in the present study and the proposed technology could be exploited by the industries of the beverage sector to increase the shelf life of these kinds of products. Moreover, from a technological point of view, the increase of viscosity, following the high-pressure homogenization treatment, represents a tool to expand the product gamma without the use of gelling additives or thermal treatments, which are detrimental for the sensorial and nutritional properties of this kind of products.     

超高压对果蔬汁品质影响研究进展

超高压技术是一种新型的非热力加工技术。文中从果蔬汁的颜色品质、香气品质、营养品质及流变特性和稳定性等角度系统介绍和分析了超高压对果蔬汁品质影响的研究现状,并分析了今后这一领域研究的趋势。     

Thermal Treatments for Fruit and Vegetable Juices and Beverages: A Literature Overview

Fruit and vegetable juices and beverages are generally preserved by thermal processing, currently being the most cost‐effective means ensuring microbial safety and enzyme deactivation. However, thermal treatments may induce several chemical and physical changes that impair the organoleptic properties and may reduce the content or bioavailability of some nutrients; in most cases, these effects are strongly dependent on the food matrix. Moreover, the efficacy of treatments can also be affected by the complexity of the product and microorganisms. This review covers researches on this topic, with a particular emphasis on products derived from different botanical sources. Technologies presented include conventional and alternative thermal treatments. Advances toward hurdle‐based technology approaches have been also reviewed.     

果汁饮料中原果汁含量检测技术的现状

综述了果汁饮料中果汁含量检测技术的现状与进展,分析比较了现行的各种果汁含量的检测方法,系统介绍了各种新型检测技术在果汁含量测定中的应用。     

D-alanine in Fruit Juices: A Molecular Marker of Bacterial Activity, Heat Treatments and Shelf-life

Apple, grapefruit, orange, peach, pear, pineapple and other commercial juice samples were investigated by GC (chiral phase) and HPLC (chiral eluent) to detect D-amino acids as molecular markers of bacterial activity, heat treatments, and shelf life. The development of D-amino acids was followed in grapefruit juice samples inoculated with bacteria (Lactobacillus plantarun), or yeasts (Saccharomyces cereviae). Significant amounts of free D-alanine were found only in juices affected by bacterial contamination. The content of D-alanine was not dependent upon pasteurization or sterilization treatments and did not change during the shelf-life of the products. D-alanine may be considered as a marker of bacterial contamination occurring before or during juice processing.     

果蔬渗透脱水技术研究进展

围绕影响渗透脱水效果及脱水过程中物质迁移的主要因素、促进物质迁移的方法、渗透脱水联合其它干燥技术对产品品质和能耗的影响等方面,对国内外果蔬渗透脱水技术的研究进展进行了综述,指出目前研究中存在的问题,并就未来的发展前景进行了展望.     

果汁中9种酚酸类化合物的RP-HPLC-PAD分析

研究了同时测定5种果汁中没食子酸、儿茶酸、绿原酸、原儿茶酸、咖啡酸、表儿茶酸、阿魏酸、莽草酸和丁香酸等9种生物活性酚酸的反相高效液相色谱-光电二极管阵列检测新方法。采用ZorbaxEclipseXDB-C18色谱柱(5μm,250mm×4.6mmi.d.),流动相为甲醇-0.5%乙酸,梯度洗脱,流速1.0mL/min,以保留时间和特征光谱对分离出的组分予以定性确证,用峰面积进行定量。9种组分的质量浓度与其峰面积在一定的范围内有良好的线性关系,相关系数为0.9987～0.9999。9种组分的平均回收率为86.5%～98.8%(相对标准偏差为3.1%～5.8%)。检测限为0.2～1.0mg/L。结果表明,该方法也适用于其他复杂体系中没食子酸等9种生物活性成分的分析。