Advances in Ultraviolet Light Technology for Non-thermal Processing of Liquid Foods

A negative, public reaction is growing over the addition of chemical preservatives to liquid foods and beverages to extend their shelf life and to protect against foodborne pathogens. As a physical method, ultraviolet light (UV) irradiation has a positive consumer image and is of interest to the food industry as a low cost non-thermal method of preservation. Recent advances in the science and engineering of UV light irradiation have demonstrated that this technology holds considerable promise as an alternative to traditional thermal pasteurization for liquid foods and ingredients, fresh juices, soft drinks, and beverages. However, its use for treating foods is still limited due to low UV transmittance of liquid foods. The goal of this review is to provide a summary of the basic principles of UV light generation and propagation with emphasis on its applications for liquid food processing. The review includes information on critical product and process factors that affect UV light inactivation and consequently the delivery of a required scheduled process in liquids foods; measuring and modeling of UV inactivation, and the important effects of UV light on overall quality and nutritional value of liquid foods. The commercially available UV light sources and UV reactor designs that were used for liquid foods treatment are reviewed. The research priorities and challenges that need to be addressed for the successful development of UV technology for liquid foods treatment are discussed.     

Ultraviolet processing of liquid food: A review: Part 2: Effects on microorganisms and on food components and properties

The effectiveness of ultraviolet irradiation in inactivating microorganisms has been known for decades. Nevertheless, in the processing of foodstuff other important issues must be considered, such as organoleptic or nutritional properties preservation. Ultraviolet irradiation constitutes an alternative to thermal treatment that is being studied and developed to obtain a better final product sensory quality, but without neglecting microbial safety. Moreover, it has been proved that this technology can be useful to decompose some toxins that are not affected by thermal processing. In this piece of work, the effect of UV irradiation on all of these contaminants and components of liquid food has been reviewed.     

Interactions between proteins and phenolics: effects of food processing on the content and digestibility of phenolic compounds

Phenolic compounds have recently become one of the most interesting topics in different research areas, especially in food science and nutrition due to their health-promoting effects. Phenolic compounds are found together with macronutrients and micronutrients in foods and within several food systems. The coexistence of phenolics and other food components can lead to their interaction resulting in complex formation. This review article aims to cover the effects of thermal and non-thermal processing techniques on the protein–phenolic interaction especially focusing on the content and digestibility of phenolics by discussing recently published research articles. It is clear that the processing conditions and individual properties of phenolics and proteins are the most effective factors in the final content and intestinal fates of phenolic compounds. Besides, thermal and non-thermal treatments, such as high-pressure processing, pulsed electric field, cold plasma, ultrasonication, and fermentation may induce alterations  in those interactions. Still, new investigations are required for different food processing treatments by using a wide range of food products to enlighten new functional and healthier food product design, to provide the optimized processing conditions of foods for obtaining better quality, higher nutritional properties, and health benefits. © 2024 Society of Chemical Industry.     

紫外线-乙醇联合使用对克洛诺菌属的协同杀菌效果

为探讨紫外线-乙醇联合使用是否对克洛诺菌属产生协同消毒效果,对0.1%稀释复原婴儿配方奶粉分别用乙醇,氢氧化钠和紫外线对克洛诺菌属NC830的杀菌效果进行了调查。结果表明,体积分数为50%和25%的乙醇处理仅引起3.65和4.05 mL-1的杀灭效果,而使用体积分数为75%的乙醇,阪崎克洛诺菌的水平下降5.46 mL-1(对数值)。质量分数为1.0%,2.5%,5.0%的氢氧化钠杀灭效果分别达到4.84,5.44和6.46mL-1(对数值)。紫外线分别作用克洛诺菌属10,20,30 min,杀灭效果分别达到1.14,2.03和2.89 mL-1(对数值)。经过30 min的处理,紫外线、乙醇和两者联合使用对阪崎克洛诺菌杀灭值分别为2.81,3.85和5.07 mL-1(对数值),紫外线-乙醇联合使用对阪崎克洛诺菌产生协同消毒效果。     

Pulsed Light Treatments for Food Preservation. A Review

Consumers demand high-quality processed foods with minimal changes in nutritional and sensory properties. Nonthermal methods are considered to keep food quality attributes better than traditional thermal processing. Pulsed light (PL) is an emerging nonthermal technology for decontamination of food surfaces and food packages, consisting of short time high-peak pulses of broad spectrum white light. It is considered an alternative to continuous ultraviolet light treatments for solid and liquid foods. This paper provides a general review of the principles, mechanisms of microbial inactivation, and applications of PL treatments on foods. Critical process parameters that are needed to be optimized for a better efficiency of PL treatments are also discussed. PL has considerable potential to be implemented in the food industry. However, technological problems need to be solved in order to avoid food overheating as well as to achieve better penetration and treatment homogeneity. In addition, a more extensive research is needed to understand how PL affects quality food attributes.     

Evaluation of key parameters during construction and operation of an ohmic heating apparatus

This study aimed to design, build and validate an ohmic heating apparatus in bench scale and evaluate its performance on liquid food processing. The equipment developed showed adequate performance, monitoring data and heating products satisfactorily. Three ohmic cells were developed and tested in the device. When acerola and blueberry pulps were heated in the ohmic heater, a nonlinear behavior of electrical conductivity with temperature was observed. This behavior is associated with bubble formation caused by water boiling due to temperature gradients inside the cells. This phenomenon is influenced by a number of factors, such as solids content, electric field strength, ohmic cell size and agitation. Two of the ohmic cells developed, when placed on agitating devices, are suitable for a uniform heat treatment of liquid foods. The ohmic heating apparatus developed is adequate to conduct studies to better understand this technology and its applications on food processing.Industrial relevanceThe apparatus of ohmic heating for liquid foods designed and tested in this work can be used to evaluate fundamental parameters, such as electrical conductivity of the product, heating time and process homogeneity. It also provides a tool to monitor processing effects on the quality of end products in order to find the best conditions for a continuous ohmic heating process in an industrial scale.     

Evaluation of a new multipurpose centrifugal mechanism for nut process

Post processing and transportation of pistachio have great effects on its food value, physical properties and marketability of this product. Any applicable research for processing of pistachio have direct and indirect effects on developing technology of this industry. In this study, various methods of pistachio and other nut processing in recent years have been investigated and after that, new suitable and multipurpose centrifugal mechanism for nut processing have been presented. The mechanism is able to do hulling, washing and draining, all in one. The machine has been constructed in the laboratory and loaded with pistachio in two treatments and with walnuts in four treatments. In both hulling and draining processes good results are obtained. Time did not play as an important role for hulling process. Bigger nuts with higher inertia like walnuts were hulled better in this system.     

高强脉冲电场对食品成分的影响

强脉冲电场是近年来发展起来的一项非热食品绿色加工新技术,有望取代传统热处理技术,从而引起了业内广泛关注.本文综述了强脉冲电场处理对液态食品品质和成分的影响,与热处理相比,强脉冲电场处理具有保存食品原有风味和营养价值的特性.     

Innovative food processing technologies on the transglutaminase functionality in protein-based food products: Trends,opportunities and drawbacks

BackgroundConsumption of protein-based food products has a key role in the improvement of human health. The crosslinking agent microbial transglutaminase (mTGase) is an effective and promising tool to modify animal proteins used in the food industry. Improvement in the gelation process, physicochemical and textural quality, and consumer's demand of protein-based food products could be attained by combining mTGase and some non-conventional food processing technologies.Scope and approachNew perspectives and key areas for future research in the development of high-quality food proteins and protein-based products as a function of interaction effect of mTGase and some new processing techniques (e.g. high pressure processing (HPP), ultrasound, microwave (MW) and ultraviolet (UV) irradiation) are reviewed. The effect of conventional thermal and emerging processing methods on the mTGase crosslinking activity and protein gel functionality are also compared.Key findings and conclusionsThe crosslinking density and functional properties of protein gels can be strongly promoted by the synergistic action of mTGase and innovative processing methods. Compared to the conventional heating, HPP with further increase of mTGase affinity to proteins can result in products with better physicochemical quality and more complex and firmer gel structure. The yield, water holding capacity, surface hydrophobicity, strength, and viscoelastic characteristics of mTGase-catalyzed protein gels can be significantly increased by ultrasonication treatments. mTGase-crosslinked hydrogels subjected to high-intensity ultrasonic pretreatment have potential to be used as delivery vehicles for a wide spectrum of bioactive compounds. The application of MW and UV light can substantially improve the surface, textural and structural features of gels generated by mTGase-technology.     

Surface Processing: Existing and Potential Applications of Ultraviolet Light

Solid foods represent optimal matrices for ultraviolet processing with effects well beyond nonthermal surface disinfection. UV radiation favors hormetic response in plant tissues and degradation of toxic compound on the product surface. Photoinduced reactions can also provide unexplored possibilities to steer structure and functionality of food biopolymers. The possibility to extensively exploit this technology will depend on availability of robust information about efficacious processing conditions and adequate strategies to completely and homogeneously process food surface.     

Electrical Conductivities of Liquid Egg Products and Fruit Juices Exposed to High Pulsed Electric Fields

Electrical conductivity can be used to monitor important changes in a food product during pulsed electric field (PEF) processing. Electrical conductivities of selected fruit juices (namely apple, orange, and pineapple juices) and liquid egg products (namely whole egg, yolk, and egg white) were determined online during a PEF treatment. The property was measured at broad processing temperatures ranging from 5 to 55°C. Electrical conductivity increased linearly with increasing temperatures for all the products. The liquid egg products have the highest overall electrical conductivity varying from 0.22 to 1.1 S/m whereas fruit juice products have the lowest electrical conductivity ranging from 0.13 to 0.63 S/m. Regression equations of electrical conductivity as functions of temperature were developed. This paper provides a database and equation correlations of food electrical conductivity that could be used to design and optimize PEF process.     

Nonthermal Plasma–Liquid Interactions in Food Processing: A Review

Nonthermal processing methods are often preferred over conventional food processing methods to ensure nutritional quality. Nonthermal plasma (NTP) is a new field of nonthermal processing technology and seeing increased interest for application in food preservation. In food applications of NTP, liquid interactions are the most prevalent. The NTP reactivity and product storability are altered during this interaction. The water activated by NTP (plasma‐activated water [PAW]) has gained considerable attention during recent years as a potential disinfectant in fruits and vegetable washing. However, detailed understanding of the interactions of NTP reactive species with food nutritional components in the presence of water and their stability in food is required to be explored to establish the potential of this emerging technology. Hence, the main objective of this review is to give a complete overview of existing NTP–liquid interactions. Further, their microbial inactivation mechanisms and the effects on food quality are discussed in detail. Most of the research findings have suggested the successful application of NTP and PAW for microbial inactivation and food preservation. Still, there are some research gaps identified and a complete analysis of the stability of plasma reactive species in food is still missing. By addressing these issues, along with the available research output in this field, it is possible that NTP can be successfully used as a food decontamination method in the near future.     

Nonthermal Technologies for Fruit and Vegetable Juices and Beverages: Overview and Advances

In recent years, there has been a growing interest in the design of novel nonthermal processing systems that minimally modify sensory, nutritional, and functional properties of fruit and vegetable juices and beverages. The benefits of nonthermal treatments are strongly dependent on the food matrix. Thus, an understanding of the effects that these technologies exert on the properties of juices and beverages is important to design and optimize technological parameters to produce value‐added products. This review covers research on nonthermal electrical treatments, high pressure processing, ultrasound, radiation processing, inert gas treatments, cold plasma, and membrane processing. Advances towards optimization of processing conditions, and combined technologies approaches have been also extensively reviewed. This information could be useful to: (1) manage processing systems and optimize resources; (2) preserve nutritional value and organoleptic properties, and (3) provide processing conditions for validation of these technologies at the industrial scale.     

Fluence (UV dose) distribution assessment of UV-C light at 254 nm on food surfaces using radiochromic film dosimetry integrated with image processing and convolutional neural network (CNN)

Uniform Fluence (UV Dose) distribution on food surfaces is essential for an effective UV process design. In this study, the use of radiochromic films (RCFs) with a computer vision system (CVS) integrating image processing and Convolutional Neural Network (CNN) is proposed as an alternative method to assess Fluence distribution of UV-C light at 254 nm on food surfaces. The color difference of RCFs exposed to different UV irradiance and exposure times was correlated with Fluence. The validity of the developed methodology was proved by applying it to the surface of apple fruits of different shapes and sizes. A linear relationship was found between the color difference of RCF and Fluence. The maximum Fluence to be determined using RCFs was ∼60 mJ/cm². The color of the films after UV irradiation remained stable for up to 15 days in darkness when stored at room and refrigeration temperatures. The results showed that RCF can be used as an alternative UV dosimeter.     

不同仪器检测方法及标准品对保健食品中茶多酚含量测定的影响

目的以茶多酚及没食子酸为标准品,分别采用紫外分光光度法及高效液相色谱法测定保健食品中茶多酚含量。方法通过对市场上部分宣称含茶多酚的保健食品进行测定,探讨不同仪器检测方法、不同标准物质对保健食品中茶多酚含量的影响。结果高效液相色谱法测定的结果均低于紫外分光光度法,其中紫外分光度法测定中,以茶多酚为标准品测定结果低于以没食子酸为标准品的结果。结论测定保健食品样品中茶多酚含量时,应根据产品的原辅料及目的进行仪器方法及标准品的选择。     

Formation of 4‐hydroxynonenal (4‐HNE) in frozen mackerel (Scomber scombrus) in the presence and absence of green tea

BACKGROUND: Aldehydes are secondary lipid oxidation products formed during processing and storage of food. 4‐Hydroxynonenal (4‐HNE) is a major toxic lipid peroxidation product which has been extensively investigated in the clinical field but less so in food products. The aim of the present study was to investigate the formation of aldehydes in stored frozen fish (Atlantic mackerel, Scomber scombrus) with and without antioxidant (green tea). RESULTS: The presence of 4‐HNE in frozen fish was detected for the first time. 4‐HNE was extracted from frozen fish and identified using high‐performance liquid chromatography and liquid chromatography/mass spectrometry. The amount of 4‐HNE increased throughout storage for 26 weeks at ? 10 °C in the absence of antioxidant. A significant decrease was observed in fish samples stored at ?10 °C with green tea. Minimal amounts of 4‐HNE were formed in fish stored at ?80 °C. A similar increase in 4‐HNE was found for methyl linoleate and extracted fish oil exposed to UV irradiation. CONCLUSION: The toxic aldehyde 4‐HNE can be formed in badly stored frozen mackerel and is an indicator of reduced texture quality and nutritional value of fish. Addition of instant whole green tea as an antioxidant can provide a cheap and effective way of enhancing safety, especially in developing countries. Copyright © 2008 Society of Chemical Industry     

Effect of novel food processing methods on packaging: structure, composition, and migration properties

Classical stabilization techniques (thermal treatments) usually involve food to be packed after being processed. On the contrary and increasingly, novel food processing methods, such as high pressure or microwaves, imply that both packaging and foodstuff undergo the stabilization treatment. Moreover, novel treatments (UV light, irradiation, ozone, cold plasma) are specifically used for disinfection and sterilization of the packaging material itself. Therefore, in the last several years a number of papers have focused on the effects of these new treatments on food-packaging interactions with a special emphasis on chemical migration and safety concerns. New packaging materials merged on the market with specific interest regarding the environment (i.e. bio-sourced materials) or mechanical and barrier properties (i.e. nanocomposites packaging materials). It is time to evaluate the knowledge about how these in-package food technologies affect food/packaging interactions, and especially for novel biodegradable and/or active materials. This article presents the effect of high pressure treatment, microwave heating, irradiation, UV-light, ozone and, cold plasma treatment on food/packaging interactions.     

高密度CO2在肉制品和水产品加工中的应用

高密度CO2是一种新型的非热食品加工技术,具有加工条件温和、对热敏物质破坏小、能有效保持食品营养、风味和新鲜度等许多优点。近年来,高密度CO2在食品加工领域的应用研究越来越多,但目前研究主要集中在液体食品的杀菌效果和动力学、钝酶效果和动力学、及其对品质的影响方面;由于固体食品体系复杂,CO2不易渗透,使得高密度CO2处理固体食品的研究还相对较少。本文重点对高密度CO2在肉制品和水产品加工中应用的研究进展进行综述,分析高密度CO2对肉制品和水产品的杀菌、肌肉品质(pH、色泽、保水性、质构、嫩度、营养成分、呈味成分等)、蛋白质等的影响规律和作用机理,并对今后高密度CO2加工技术的研究重点进行展望,为推动高密度CO2在肉制品和水产品加工中的应用研究和产业化提供参考。