Emerging technologies: chemical aspects

Consumer demands for high-quality foods with “fresh-like” characteristics that require only a minimum amount of effort and time for preparation has led to the introduction of convenience foods preserved by mild treatments. Non-thermal methods allow the processing of foods below temperatures used during thermal pasteurisation, so flavours, essential nutrients, and vitamins undergo minimal or no changes. Foods can be non-thermally processed by irradiation, high hydrostatic pressure, antimicrobials, ultrasound, filtration, and electrical methods such as pulsed electric fields, light pulses, and oscillating magnetic fields. Due to technological developments, high pressure processing and high electric field pulse processing have received increased attention during the last decade. This paper focuses on high pressure treatment of foods, a process which is also used to create food and food ingredients with new sensory and functional properties including also physiological functionality. Effects of high pressure on chemical and sensory changes in foods are discussed.     

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.     

Molecular Dynamics Simulation for Mechanism Elucidation of Food Processing and Safety: State of the Art

Molecular dynamics (MD) simulation is a useful technique to study the interaction between molecules and how they are affected by various processes and processing conditions. This review summarizes the application of MD simulations in food processing and safety, with an emphasis on the effects that emerging nonthermal technologies (for example, high hydrostatic pressure, pulsed electric field) have on the molecular and structural characteristics of foods and biomaterials. The advances and potential projection of MD simulations in the science and engineering aspects of food materials are discussed and focused on research work conducted to study the effects of emerging technologies on food components. It is expected by showing key case studies that it will stir novel developments as a valuable tool to study the effects of emerging food technologies on biomaterials. This review is useful to food researchers and the food industry, as well as researchers and practitioners working on flavor and nutraceutical encapsulations, dietary carbohydrate product developments, modified starches, protein engineering, and other novel food applications.     

高压加工技术在水产品中的应用

高压加工技术是目前食品工业中热门加工技术之一,它能够保持食品的天然风味,但这种方法目前在水产品中应用还不是很多,本文综述了高压加工技术对水产品中微生物和水产品品质的影响。     

高压对牛乳理化性质和成分的影响

高压食品加工是一种非热杀菌技术,是指在室温或低温下用100-800MPa高压处理食品。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,而对食品的营养成分和感官品质改变较小。本文综述了高压处理对牛奶物理化学性质和成分的影响。     

Food Process Engineering: The Last 25 Years and Challenges Ahead

In the first part of this contribution, an overview is given of some of the main developments in food process engineering in the last 25 years of the 20th century. This overview is, of course, colored by the personal experience of the authors, but a sincere effort was made to maintain a general perspective. Topics that will be briefly discussed are: progress in understanding how to control food microstructure formation during processing, separation processes, conversion processes and stabilization processes, progress in flavor technology and understanding of flavor retention during processing and release. In the 2nd part, in our view, the most exiting future developments are briefly discussed. The major items here are: processing requirements for functional foods, integrated process design approaches, application of novel‘fields’in food processes,‘precision’processing, supply chain approaches to food manufacturing, and more.     

Effects of high pressure processing on antioxidant activity, and total carotenoid content and availability, in vegetables

High pressure processing (HPP) is a relatively new food preservation processing technology that enhances food safety and shelf-life without compromising organoleptic qualities. There has been little research on the impact of HPP on the nutritional and health-promoting properties of foods to date and most of it has focused on juices and purees of fruit such as oranges and tomatoes. The objective of this study was to determine the effects of HPP treatment at two pressure levels (400 MPa; 600 MPa) on antioxidant activity, total carotenoid content and carotenoid availability in vitro, of three commonly consumed vegetables. Antioxidant capacity and total carotenoid content differed between vegetables but were unaffected by HPP treatment. In vitro availability of specific carotenoids also varied greatly between vegetables (3–35%). HPP altered availability of carotenoids according to the type of vegetable treated and processing pressure applied, however the magnitude of the responses was minor.

Industrial relevance

This study provides further scientific evidence of the benefits of high pressure processing in retaining the nutritional attributes of fresh foods. Antioxidant activity and levels of carotenoids before and after exposure to high pressures (up to 600 MPa for 2 min) were essentially no different. Also, the data suggest that micronutrients and phytochemicals in certain vegetables may be made more bioavailable by high pressure treatment. From a nutritional perspective, high pressure processing is an attractive food preservation technology and clearly offers opportunities for horticultural and food processing industries to meet the growing demand from consumers for healthier food products.     

Texture Modification Technologies and Their Opportunities for the Production of Dysphagia Foods: A Review

Dysphagia or swallowing difficulty is a common morbidity experienced by those who have suffered a stroke or those undergone such treatments as head and neck surgeries. Dysphagic patients require special foods that are easier to swallow. Various technologies, including high‐pressure processing, high‐hydrodynamic pressure processing, pulsed electric field treatment, plasma processing, ultrasound‐assisted processing, and irradiation have been applied to modify food texture to make it more suitable for such patients. This review surveys the applications of these technologies for food texture modification of products made of meat, rice, starch, and carbohydrates, as well as fruits and vegetables. The review also attempts to categorize, via the use of such key characteristics as hardness and viscosity, texture‐modified foods into various dysphagia diet levels. Current and future trends of dysphagia food production, including the use of three‐dimensional food printing to reduce the design and fabrication time, to enhance the sensory characteristics, as well as to create visually attractive foods, are also mentioned.     

Recent developments in novel freezing and thawing technologies applied to foods

This article reviews the recent developments in novel freezing and thawing technologies applied to foods. These novel technologies improve the quality of frozen and thawed foods and are energy efficient. The novel technologies applied to freezing include pulsed electric field pre-treatment, ultra-low temperature, ultra-rapid freezing, ultra-high pressure and ultrasound. The novel technologies applied to thawing include ultra-high pressure, ultrasound, high voltage electrostatic field (HVEF), and radio frequency. Ultra-low temperature and ultra-rapid freezing promote the formation and uniform distribution of small ice crystals throughout frozen foods. Ultra-high pressure and ultrasound assisted freezing are non-thermal methods and shorten the freezing time and improve product quality. Ultra-high pressure and HVEF thawing generate high heat transfer rates and accelerate the thawing process. Ultrasound and radio frequency thawing can facilitate thawing process by volumetrically generating heat within frozen foods. It is anticipated that these novel technologies will be increasingly used in food industries in the future.     

New and future uses of enzymes in food processing

Enzymes are often thought of by the food processing industry as detrimental, to be destroyed by heat treatment. This is based on undesirable changes in texture, color, flavor, aroma and nutrition that may occur on harvest and storage. However, the uses of enzymes in brewing, cheese manufacture, meat tenderization, baking and protein hydrolysis are well known, having been used for many years. Of more recent utilization are enzymes for making glucose and fructose from starch, for separating racemic mixtures of D‐and L‐amino acids, for cleaning of processing equipment, for changes in functionality of high protein foods and increasing juice yield and clarity.

In the last five years there has been renewed interest in developing additional uses of enzymes for food processing. In general, these methods require much more specificity and controlled conditions than previous methods. These methods include use of lipases for transesterification of triglycerides, production of specific monoglycerides and high molecular weight mono fatty acid esters and waxes, production of noncaloric sweeteners, production of controlled size peptides with enhanced functional properties including solubility, removal of unwanted toxic or antinutritional factors, for more precise control of heat processing of foods, for enhanced flavor development, as tools in production of transgenic plants, animals, and microorganisms and for food analysis. Examples of these and other new uses of enzymes in foods will be presented.     

Pulsed electric field processing of foods: a review.

Use of pulsed electric fields (PEFs) for inactivation of microorganisms is one of the more promising nonthermal processing methods. Inactivation of microorganisms exposed to high-voltage PEFs is related to the electromechanical instability of the cell membrane. Electric field strength and treatment time are the two most important factors involved in PEF processing. Encouraging results are reported at the laboratory level, but scaling up to the industrial level escalates the cost of the command charging power supply and of the high-speed electrical switch. In this paper, we critically review the results of earlier experimental studies on PEFs and we suggest the future work that is required in this field. Inactivation tests in viscous foods and in liquid food containing particulates must be conducted. A successful continuous PEF processing system for industrial applications has yet to be designed. The high initial cost of setting up the PEF processing system is the major obstacle confronting those who would encourage the system's industrial application. Innovative developments in high-voltage pulse technology will reduce the cost of pulse generation and will make PEF processing competitive with thermal-processing methods.     

Food Waste Management and Value-added Products

ABSTRACT: Optimization of thermal treatments has been proven to enhance the quality of food products, especially when operated together with a validation method that confirms the safety of the processing operations. Recent developments in the understanding and application of pasteurization treatments have allowed this area to grow at a rapid rate. UK and European consumers now have a wide variety of high-quality pasteurized foods to choose from in the retail and catering markets. Food producers have used this to their advantage by converting processing operations from severe treatments such as sterilization to milder ones that can be categorized under the pasteurization umbrella. This has increased food product quality and added value to existing products. Two examples will be given, both of which utilized a novel validation method based on time-temperature integrators to provide process safety data that were difficult to obtain by alternative methods. The first was in applying a novel processing technology, ohmic heating, to produce higher-quality fruit products when compared with traditional processing methods. The second was in the production of high-quality sous vide ready meals supplied chilled or frozen to the catering sector. These developments in technology and validation have been made possible by work at CCFRA that has taken the pasteurized foods sector forward. CCFRA has been active in pasteurization research for many years and has produced industry guideline documents on, for example, pasteurization treatments and sous vide processing. Microbiological research on the growth and death of target microorganisms has been linked with processing, hygiene, and validation research, which provided the underpinning science for these guidelines. Food manufacturers work closely with CCFRA to apply their pasteurization processes in order to produce high-quality value-added products.     

高静压加工优化食品酶催化体系:现状与趋势

作为新兴的非热加工前沿技术,超高压食品加工已成为现代健康食品制造领域的研究热点.将其应用于优化食品酶催化体系,对指导现代食品生物加工具有重要意义.基于高静压加工优化食品酶催化体系研究已有几十年,将其成果加以总结,并分析存在的问题,有利于更好地促进现代食品加工的发展.本文综述了高静压加工优化食品酶催化体系的发展现状,分析提炼了科学问题,在此基础上提出本领域若干研究方向,期望能对相关领域研究者有所启发.     

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。     

The Issue of Undeclared Ingredients in Halal and Kosher Food Production: A Focus on Processing Aids

Since the early 1900s the food industry has undergone major advances that have led to more than half of the shelves in a modern supermarket being stocked with packaged and processed foods. These boxed, canned, and frozen foods achieve their convenience by using a number of food ingredients and processing aids. The original sources and the details of their processing prior to inclusion in the final food product are not provided to consumers but will determine their acceptability for both halal and kosher food production. While additives are generally declared on a product label, processing aids are not shown on the ingredient statement and thus the consumer is not even aware of their presence. Some additives can be legally grouped into generic categories (such as spices) that also make it difficult for consumers to determine what exactly is in the products they buy and how these products have been processed. Thus, consumers need to put more pressure on the kosher and halal marketing system to use trademarked symbols that represent an organization that the consumer can hold accountable and which provides both the companies and the consumer with confidence in the kosher and/or halal status of the products being offered in the marketplace.     

Effects of combined pressure and temperature on enzymes related to quality of fruits and vegetables: from kinetic information to process engineering aspects

Throughout the last decade, high pressure technology has been shown to offer great potential to the food processing and preservation industry in delivering safe and high quality products. Implementation of this new technology will be largely facilitated when a scientific basis to assess quantitatively the impact of high pressure processes on food safety and quality becomes available. Besides, quantitative data on the effects of pressure and temperature on safety and quality aspects of foods are indispensable for design and evaluation of optimal high pressure processes, i.e., processes resulting in maximal quality retention within the constraints of the required reduction of microbial load and enzyme activity. Indeed it has to be stressed that new technologies should deliver, apart from the promised quality improvement, an equivalent or preferably enhanced level of safety. The present paper will give an overview from a quantitative point of view of the combined effects of pressure and temperature on enzymes related to quality of fruits and vegetables. Complete kinetic characterization of the inactivation of the individual enzymes will be discussed, as well as the use of integrated kinetic information in process engineering.     

Current status of emerging food processing technologies in Latin America: Novel non-thermal processing

Non-thermal emerging technologies in the sector of food processing have often been cited by researchers as an alternative to conventionally heat treatments for food processing in order to develop safe foods with minimal damage to nutritional and sensory properties. Non-thermal emerging technologies for foods processing have been widely developed in Europe and U.S.A. However, the interest in these technologies and commercialisation opportunities started catching up in Latin America. Thus, this review describes the basic principles and main effect of this technologies in the food and the recent scientific reports on its applications and potential advantages of the so-called non-thermal emerging technologies like ultrasound, high hydrostatic pressure, pulsed electric field, ionising radiation and atmospheric cold plasma, as alternative food preservation process. This review focuses on the current status in Latin America of novel non-thermal food processing technologies, highlighting the limits for scaling up to industrial level in order to be commercially successful.     

Aspects of high hydrostatic pressure food processing: Perspectives on technology and food safety

The last two decades saw a steady increase of high hydrostatic pressure (HHP) used for treatment of foods. Although the science of biomaterials exposed to high pressure started more than a century ago, there still seem to be a number of unanswered questions regarding safety of foods processed using HHP. This review gives an overview on historical development and fundamental aspects of HHP, as well as on potential risks associated with HHP food applications based on available literature. Beside the combination of pressure and temperature, as major factors impacting inactivation of vegetative bacterial cells, bacterial endospores, viruses, and parasites, factors, such as food matrix, water content, presence of dissolved substances, and pH value, also have significant influence on their inactivation by pressure. As a result, pressure treatment of foods should be considered for specific food groups and in accordance with their specific chemical and physical properties. The pressure necessary for inactivation of viruses is in many instances slightly lower than that for vegetative bacterial cells; however, data for food relevant human virus types are missing due to the lack of methods for determining their infectivity. Parasites can be inactivated by comparatively lower pressure than vegetative bacterial cells. The degrees to which chemical reactions progress under pressure treatments are different to those of conventional thermal processes, for example, HHP leads to lower amounts of acrylamide and furan. Additionally, the formation of new unknown or unexpected substances has not yet been observed. To date, no safety-relevant chemical changes have been described for foods treated by HHP. Based on existing sensitization to non-HHP-treated food, the allergenic potential of HHP-treated food is more likely to be equivalent to untreated food. Initial findings on changes in packaging materials under HHP have not yet been adequately supported by scientific data.     

Packaging under pressure: Effects of high pressure, high temperature processing on the barrier properties of commonly available packaging materials

High pressure thermal (HPT) processing has the potential to deliver quality benefits to a range of processed foods. By exploiting the rapid temperature increase/decrease that accompanies pressurization/depressurization, commercial sterilization of foods can potentially be achieved by HPT with an overall reduced thermal exposure compared with conventional thermal processing technologies. High pressure thermal sterilization (HPTS) of foods is yet to be commercialized, but during development of the technology some potential limitations have been raised about the suitability for HPTS of commercially available packaging materials developed for retort processing. Key requirements of packaging materials for thermally processed foods are the preservation of oxygen and water barriers during processing and for the duration of the shelf life of the food. We examined the barrier properties after HPT processing of eleven commercially available packaging materials developed for conventional thermal sterilization processes. We found that the barrier properties of vapor-deposited oxide and nylon containing films were compromised by the combination of high pressure (600 MPa) and high temperature ( 110 °C) which would be reasonably expected to be required to render food commercially sterile by HPT processing. However, the barrier properties of aluminium foil and PVDC–MA containing films were not significantly affected by HPT processing. All materials suffered cosmetic deformation of the outer surface to some degree and mechanisms for these changes are proposed.

Industrial relevance

Information on the barrier properties of flexible packaging suitable for foods sterilized by HPT processing has been scarcely reported. This study provides information on the barrier properties of commercially available, retortable films processed under high pressure/high temperature conditions and identifies candidate packaging based on barrier performance.     

Principles and recent applications of novel non-thermal processing technologies for the fish industry—a review

Thermal treatment is a traditional method for food processing, which can kill microorganisms but also lead to physicochemical and sensory quality damage, especially to temperature-sensitive foods. Nowadays consumers’ increasing interest in microbial safety products with premium appearance, flavor, great nutritional value and extended shelf-life has promoted the development of emerging non-thermal food processing technologies as alternative or substitution to traditional thermal methods. Fish is an important and world-favored food but has a short shelf-life due to its extremely perishable characteristic, and the microbial spoilage and oxidative process happen rapidly just from the moment of capture, making it dependent heavily on post-harvest preservation. The applications of novel non-thermal food processing technologies, including high pressure processing (HPP), ultrasound (US), pulsed electric fields (PEF), pulsed light (PL), cold plasma (CP) and ozone can extend the shelf-life by microbial inactivation and also keep good sensory quality attributes of fish, which is of high interest for the fish industry. This review presents the principles, developments of emerging non-thermal food processing technologies, and also their applications in fish industry, with the main focus on microbial inactivation and sensory quality. The promising results showed great potential to keep microbial safety while maintaining organoleptic attributes of fish products. What’s more, the strengths and weaknesses of these technologies are also discussed. The combination of different food processing technologies or with advanced packaging methods can improve antimicrobial efficacy while not significantly affect other quality properties under optimized treatment.