高压脉冲电场对食品微生物、酶及成分的影响

高压脉冲电场加工是一种非热杀菌技术,是指在高电场强度、短脉冲和温和的温度下处理食品。与传统的热杀菌比较,它具有很多优点,不仅能杀死微生物钝化酶类,而且能保持食品的营养成分和新鲜度。本文综述了高压脉冲电场对食品的杀菌效果、杀菌机制、影响杀菌的因素以及对食品中酶类和成分的影响。     

高压脉冲电场非热杀菌技术研究进展

高压脉冲电场杀菌能保持食品的原有风味、具有处理时间短、能耗低。本文介绍了高压脉冲电场杀菌的原理、工艺流程、影响因素、处理效果及其研究现状和进展。该项技术有望部分取代现有的食品热杀菌技术。     

超高压技术在食品行业的应用

超高压技术（压力150—600MPa）是一种运用物理方法,在低温或常温下达到杀菌目的的冷杀菌技术,该技术克服了热杀菌和化学杀菌的不足。经高压处理可使食品中蛋白质变性,淀粉糊化,酶失活,从而杀死微生物,能较完整的保留食品的香味和多种维生素等小分子物质;同时高压处理的压力可以瞬间均匀的传到食品中心,不受原料大小和形状的限制。超高压技术具有延长食品保藏时间,     

非热杀菌技术杀灭食品中芽孢效能及机理研究进展

传统热杀菌会对食品品质产生不利影响,造成食品颜色变化、产生异味、营养损失等不良后果;非热杀菌技术是食品工业新型加工技术,处理过程中可以保持相对较低的温度,对食品的色、香、味以及营养成分影响较小;同时有利于保持食品中各种功能成分的生理活性,可以满足消费者对高品质食品的要求。芽孢在加工过程中抗性强,在食品中萌发和生长的潜力较大,因此,利用低热或非热灭菌技术对芽孢进行灭活是当前食品工业面临的严峻挑战和重要课题。本文综述现有非热杀菌技术（如高静压技术、高压CO2技术、低温等离子体技术、紫外辐射技术、高压脉冲电场技术等）独立处理或与其他处理技术相结合对芽孢灭活的效果及其机理,着重讨论其在食品行业中的应用以及芽孢灭活的分子机制,以期为生产安全食品、减少不同种类食品中微生物污染提供解决方案。     

高压技术在食品工业中的应用研究

研究了常温下高压对不同食品素材的处理情况。从对微生物、维生素、酶、感官等几方面的影响来综合评定高压处理的效果。针对不同的素材设计了不同的处理方法。试验表明，果汁和蔬菜汁经高压处理后可以达到杀菌效果，而且Vc损失很少，残存酶活只有4％，色香味等感官指标不变．其综合效果明显优于热杀菌。动物性食品也能达到杀菌效果，并且产生了前所未有的愉快而独特的风味。     

高压脉冲电场杀菌系统的研究进展

杀菌是食品加工处理过程中的一个重要工序。杀菌效果的好坏直接影响食品的安全与卫生,传统的杀菌技术会对食品的营养价值和风味产生一定的副作用。高压脉冲电场(PEF)杀菌技术因其杀菌效果好、快速、低耗、安全等优点而被广泛地用于食品杀菌中。文章介绍国内外高压脉冲电场杀菌技术对高压脉冲发生器、处理室、杀菌系统的影响,并综述对其应用的研究。     

超高压食品灭菌技术

消费者对于食品的要求一般是食用安全、性质稳定、不加添加剂。为了延长食品的保藏时间,需采用一些方法处理食品,杀死其中大部分或全部的微生物,这种处理方法即杀菌技术。 杀菌是食品生产加工中一个非常重要的环节。根据杀菌时温度不同,杀菌可分为热杀菌和冷杀菌。其中冷杀菌又根据使用手段不同分为物理杀菌和化学杀菌。冷杀菌中的物理杀菌是目前杀菌技术发展的趋势。物理杀菌克服了热杀菌和化学杀菌的不足之处,是运用物理方法,如高压、场（包括电场、磁场）、电子、光等的单一作用或两种以上的共同作用,在低温或常温下达到杀菌的目…     

超高压食品灭菌技术

消费者对于食品的要求一般是食用安全、性质稳定、不加添加剂。为了延长食品的保藏时间 ,需采用一些方法处理食品 ,杀死其中大部分或全部的微生物 ,这种处理方法即杀菌技术是食品生产加工中一个非常重要的环节。根据杀菌时温度不同 ,杀菌可分为热杀菌和冷杀菌。其中冷杀菌又根据使用手段不同分为物理杀菌和化学杀菌。冷杀菌中的物理杀菌是目前杀菌技术发展的趋势。物理杀菌克服了热杀菌和化学杀菌的不足之处 ,是运用物理方法 ,如高压、场 (包括电场、磁场 )、电子、光等的单一作用或两种以上的共同作用 ,在低温或常温下达到杀菌的目的。超高…     

高压脉冲电场杀菌多物理场特性研究

高压脉冲电场(pulsed electric fields,PEF)杀菌技术是当今备受关注的非热杀菌技术之一。处理室作为高压脉冲电场的重要组成单元,其主要功能是利用强电场力作用,在食品物料通过处理室时,使其中微生物的细胞结构在极短时间内遭到破坏,菌体死亡,从而达到杀菌效果。处理室中电场强度和温度分布是影响系统杀菌效果和食品质量的主要因素,通过对处理室内流体动力学与电场和温度场的耦合数值模拟对其进行有效解析。数值模拟的主要目的是优化处理室的几何结构,进而改善电场强度和温度分布的均匀性,从而避免局部食品物料的过处理、欠处理以及介质击穿等现象。文章总结数值模拟方法在高压脉冲电场性能研究中的应用,重点分析说明数值模拟方法在处理室内流体动力学、电场强度和温度场等方面的研究,并对该方法在高压脉冲电场应用中的进一步研究进行展望。     

食品非热杀菌技术

食品非热杀菌技术系指不使用热能杀死食品中微生物,最大限度保持食品原有营养、质构、色泽和风味的一类新型杀菌技术;该文重点介绍超高压杀菌、高压脉冲电场杀菌、等离子体杀菌、紫外线杀菌、臭氧杀菌等非热杀菌技术原理、特点及其在食品工业中应用。     

Application of High Pressure with Homogenization,Temperature, Carbon Dioxide,and Cold Plasma for the Inactivation of Bacterial Spores: A Review

Formation of highly resistant spores is a concern for the safety of low‐acid foods as they are a perfect vehicle for food spoilage and/or human infection. For spore inactivation, the strategy usually applied in the food industry is the intensification of traditional preservation methods to sterilization levels, which is often accompanied by decreases of nutritional and sensory properties. In order to overcome these unwanted side effects in food products, novel and emerging sterilization technologies are being developed, such as pressure‐assisted thermal sterilization, high‐pressure carbon dioxide, high‐pressure homogenization, and cold plasma. In this review, the application of these emergent technologies is discussed, in order to understand the effects on bacterial spores and their inactivation and thus ensure food safety of low‐acid foods. In general, the application of these novel technologies for inactivating spores is showing promising results. However, it is important to note that each technique has specific features that can be more suitable for a particular type of product. Thus, the most appropriate sterilization method for each product (and target microorganisms) should be assessed and carefully selected.     

Enzyme Inactivation in Food Processing using High Pressure Carbon Dioxide Technology

High pressure carbon dioxide (HPCD) is an effective non-thermal processing technique for inactivating deleterious enzymes in liquid and solid food systems. This processing method avoids high temperatures and exerts a minimal impact on the nutritional and sensory properties of foods, but extends shelf life by inhibiting or killing microorganisms and enzymes. Indigenous enzymes in food such as polyphenol oxidase (PPO), pectin methylesterase (PME), and lypoxygenase (LOX) may cause undesirable chemical changes in food attributes, showing the loss in color, texture, and flavor. For more than two decades, HPCD has proved its effectiveness in inactivating these enzymes. The HPCD-induced inactivation of some microbial enzymes responsible for microbial metabolism is also included. This review presents a survey of the published knowledge regarding the use of HPCD for the inactivation of these enzymes, and analyzes the factors controlling the efficiency of HPCD and speculates on the underlying mechanism that leads to enzyme inactivation.     

High‐pressure processing and preservation of food

Abstract

High pressure alone or in combination with other technologies offers great potential for producing foods with natural characteristics. Pressure works independent of size and geometry of food resulting in even preservation. The preservative effect itself is influenced by a number of factors with different foods requiring different levels of pressure. Various microorganisms also vary in their response to high pressure and the effect depends on the physical state of the microorganism and the composition of the medium. Because enzymes have a high resistance to pressure, enzymatic and oxidative spoilage are the major limiting factors in shelf‐life extension of pressure‐processed foods. This paper briefly reviews the effects of high pressure on various foods, enzymes, and microorganisms; and discusses some of the advantages and disadvantages associated with the use of this technology.     

Microbial control by packaging: a review

Since early man first used a variety of natural containers to store and eat foods, significant developments in food packaging materials have provided the means to suppress microbial growth as well as protect foods from external microbial contamination. Throughout this progression, packaging materials have been developed specifically to prevent the deterioration of foods resulting from exposure to air, moisture, or pH changes associated with the food or the surrounding atmosphere. Both flexible and rigid packaging materials, alone or in combination with other preservation methods, have been developed to offer the necessary barrier, inactivation, and containment properties required for successful food packaging. Examples of flexible packaging used to inactivate microorganisms associated with foods include controlled atmosphere, vacuum, modified atmosphere, active, and edible packaging. Additionally, the combination of rigid packaging materials made from metal, glass, or plastic with heat provides the most effective and widely used method for inactivating microorganisms. As with all food products, it is necessary to integrate a HACCP-based program to assure quality throughout the packaging operation. In addition to packaging improvements, other novel technologies include the development of detectors for oxygen levels, bacterial toxins, and microbial growth, or the integration of time-temperature indicators for detection of improper handling or storage.     

Recent Advances in the Use of High Pressure as an Effective Processing Technique in the Food Industry

High pressure processing is a food processing method which has shown great potential in the food industry. Similar to heat treatment, high pressure processing inactivates microorganisms, denatures proteins and extends the shelf life of food products. But in the meantime, unlike heat treatments, high pressure treatment can also maintain the quality of fresh foods, with little effects on flavour and nutritional value. Furthermore, the technique is independent of the size, shape or composition of products. In this paper, many aspects associated with applying high pressure as a processing method in the food industry are reviewed, including operating principles, effects on food quality and safety and most recent commercial and research applications. It is hoped that this review will promote more widespread applications of the technology to the food industry.     

Thermal pasteurization requirements for the inactivation of Salmonella in foods

Thermal processing is still one of the most effective methods for inactivating undesirable microorganisms in foods. Heat is used to inactivate pathogens and in developing typical flavours, aromas, texture and colour of a cooked food. Pasteurization produces safer foods with longer shelf-life. Since mild temperatures are applied for a specified time, complementary food preservation techniques such as modified atmospheres, addition of preservatives or the use of refrigerated storage and distribution, might be needed to control the growth of the surviving microorganisms. This review starts by addressing food contamination by Salmonella spp., referring to some examples of outbreaks, and the benefits of pasteurization in terms of Salmonella inactivation. A section covering the thermal resistance studies of Salmonella in poultry and other animal-based foods is presented. Based on Salmonella thermal resistance data, minimum pasteurization times are suggested at different heating temperatures, to meet the guidelines and recommendations of governmental food agencies for meat products (7 log reduction). Validation of a minimum pasteurization time must be done for each specific food-thermal process, by inserting a thermocouple into the “coldest” spot of the food , and ensuring that this point is submitted to the minimum pasteurization value required. This procedure will guarantee food safety with respect to Salmonella. Salmonella pasteurization requirements of low moisture foods such as some nuts, chocolate and peanut butter are also reviewed.     

发酵类食品中微生物鉴定方法及功能研究进展

发酵类食品是主要通过直接接种微生物而产生特殊风味或者将食物浸入含有微生物的臭卤水中,从而获得特殊食品风味的中国传统食品。其中,采用含有微生物的卤水进行发酵是常见的发酵方式。因此,微生物在该类食品中一直扮演着一种非常重要的角色,具有较高的研究价值。本文阐述了发酵类型的食品所需要的卤水中微生物的鉴定常用方法,以及卤水微生物与风味成分的产生之间的关系,同时论述了卤水中微生物在各种发酵食品制作过程中所起到的功能特性,包括提高豆制品的营养价值、延长保质期、去除有害成分等问题,并提出了较为可行的新型发酵类食品卤水改进方向,为进一步开发理想的食品微生物发酵剂,控制有害物质的残留、拓展相关有益微生物资源的研究提供较为明确的指导方向。     

Formation risk of toxic and other unwanted compounds in pressure-assisted thermally processed foods

Consumers demand, in addition to excellent eating quality, high standards of microbial and chemical safety in shelf-stable foods. This requires improving conventional processing technologies and developing new alternatives such as pressure-assisted thermal processing (PATP). Studies in PATP foods on the kinetics of chemical reactions at temperatures (approximately 100 to 120 °C) inactivating bacterial spores in low-acid foods are severely lacking. This review focuses on a specific chemical safety risk in PATP foods: models predicting if the activation volume value (V(a) ) of a chemical reaction is positive or negative, and indicating if the reaction rate constant will decrease or increase with pressure, respectively, are not available. Therefore, the pressure effect on reactions producing toxic compounds must be determined experimentally. A recent model solution study showed that acrylamide formation, a potential risk in PATP foods, is actually inhibited by pressure (that is, its V(a) value must be positive). This favorable finding was not predictable and still needs to be confirmed in food systems. Similar studies are required for other reactions producing toxic compounds including polycyclic aromatic hydrocarbons, heterocyclic amines, N-nitroso compounds, and hormone like-peptides. Studies on PATP inactivation of prions, and screening methods to detect the presence of other toxicity risks of PATP foods, are also reviewed.     

Barosensitivity in Saccharomyces cerevisiae is Closely Associated with a Deletion of the COX1 Gene

High hydrostatic pressure causes physical stress to microorganisms; therefore, this technology may be applied to food pasteurization without introducing the unfavorable effects of thermal denaturation. However, its application is limited to high‐value foods because the treatment requires a robust steel vessel and expensive pressurization equipment. To reduce these costs, we studied the pasteurization of Saccharomyces cerevisiae using relatively moderate high‐pressure levels. A mutant strain isolated by ultraviolet mutagenesis showed significant loss of viability under high‐pressure conditions. Gene expression analysis of the mutant strain revealed that it incurred a deletion of the COX1 gene. Our results suggest that the pressure‐sensitivity can readily be introduced into industrial/food microorganisms by complementing a COX1 deleted mitochondria.