Non-thermal Processing Technique Research Articles

Applications of cold plasma technique to enhance the safety and quality of different food products

Cold plasma (CP) has emerged as a novel technology for food processing. Its uses have been expanded into the food industry globally as an effective non-thermal processing technique with various applications. CP treatment uses reactive species for microbial inactivation, mycotoxin degradation, enzyme inactivation, protein modification and hydrogenation. CP treatment improves the physiochemical properties of different food products and the antimicrobial properties of packaging films. This review article demonstrates the applications of CP treatment in different food industries. It also explains the mechanism of microbial reduction in food components by using CP. The plasma source and impact of CP on food quality and safety have been discussed. CP is a key technology to increase the shelf life of food products while enhancing their safety with minimal impact on their bioactive compounds.

Exploring the effect of high-pressure processing conditions on the deaggregation of natural major royal jelly proteins (MRJPs) fibrillar aggregates

High pressure processing is a safe and green novel non-thermal processing technique for modulating food protein aggregation behavior. However, the systematic relationship between high pressure processing conditions and protein deaggregation has not been sufficiently investigated. Major royal jelly proteins, which are naturally highly fibrillar aggregates, and it was found that the pressure level and exposure time could significantly promote protein deaggregation. The 100–200 MPa treatment favoured the deaggregation of proteins with a significant decrease in the sulfhydryl group content. Contrarily, at higher pressure levels (>400 MPa), the exposure time promoted the formation of disordered agglomerates. Notably, the inter-conversion of α-helix and β-strands in major royal jelly proteins after high pressure processing eliminates the solvent-free cavities inside the aggregates, which exerts a 'collapsing' effect on the fibrillar aggregates. Furthermore, the first machine learning model of the high pressure processing conditions and the protein deaggregation behaviour was developed, which provided digital guidance for protein aggregation regulation.

Improving the microbiological safety and quality of aquatic products using nonthermal processing.

Spoilage and deterioration of aquatic products during storage are inevitable, posing significant challenges to their suitability for consumption and the sustainability of the aquatic products supply chain. Research on the nonthermal processing of fruit juices, probiotics, dairy products, and meat has demonstrated positive outcomes in preserving quality. This review examines specific spoilage bacteria species and mechanisms for various aquatic products and discusses the principles, characteristics, and applications of six nonthermal processing methods for bacterial inhibition to maintain microbiological safety and physicochemical quality. The primary spoilage bacteria groups differ among fish, crustaceans, and shellfish based on storage conditions and durations. Four metabolic pathways utilized by spoilage microorganisms-peptides and amino acids, nitrogen compounds, nucleotides, and carbohydrates-are crucial in explaining spoilage. Nonthermal processing techniques, such as ultrahigh pressure, irradiation, magnetic/electric fields, plasma, and ultrasound, can inactivate microorganisms, thereby enhancing microbiological safety, physicochemical quality, and shelf life. Future research may integrate nonthermal processing with other technologies (e.g., modified atmosphere packaging and omics) to elucidate mechanisms of spoilage and improve the storage quality of aquatic products.

Effect of electron beam irradiation on raw goat milk: microbiological, physicochemical and protein structural analysis.

Goat milk is considered a nutritionally superior resource, owing to its advantageous nutritional attributes. Nevertheless, it is susceptible to spoilage and the persistence of pathogens. Electron beam irradiation stands as a promising non-thermal processing technique capable of prolonging shelf life with minimal residue and a high degree of automation. The effects of electron beam irradiation (2, 3, 5, and 7 kGy) on microorganisms, physicochemical properties, and protein structure of goat milk compared with conventional pasteurized goat milk (PGM) was evaluated. It was found that a 2 kGy electron beam irradiation reduces the total microbial count of goat milk by 6-logs, and the irradiated goat milk protein secondary structure showed a significant decrease in ɑ-helix content. Low irradiation doses led to microaggregation and crosslinking. In contrast, high doses (≥ 5 kGy) slightly disrupted the aggregates and decreased the particle size, disrupting the microscopic surface structure of goat milk, verified by scanning electron microscopy and confocal laser scanning microscopy. The irradiation of goat milk with a 2 kGy electron beam may effectively inactivate harmful microorganisms in the milk and maintain/or improve the physicochemical quality and protein structure of goat milk compared to thermal pasteurization. © 2024 Society of Chemical Industry.

Possible interactions between selected food processing and medications.

The impact of food processing on drug absorption, metabolism, and subsequent pharmacological activity is a pressing yet insufficiently explored area of research. Overlooking food-processing-drug interactions can significantly disrupt optimal clinical patient management. The challenges extend beyond merely considering the type and timing of food ingestion as to drug uptake; the specific food processing methods applied play a pivotal role. This study delves into both selected thermal and non-thermal food processing techniques, investigating their potential interference with the established pharmacokinetics of medications. Within the realm of thermal processing, conventional methods like deep fat frying, grilling, or barbecuing not only reduce the enteric absorption of drugs but also may give rise to side-products such as acrylamide, aldehydes, oxysterols, and oxyphytosterols. When produced in elevated quantities, these compounds exhibit enterotoxic and pro-inflammatory effects, potentially impacting the metabolism of various medications. Of note, a variety of thermal processing is frequently adopted during the preparation of diverse traditional herbal medicines. Conversely, circumventing high heat through innovative approaches (e.g., high-pressure processing, pulsed electric fields, plasma technology), opens new avenues to improve food quality, efficiency, bioavailability, and sustainability. However, it is crucial to exercise caution to prevent the excessive uptake of active compounds in specific patient categories. The potential interactions between food processing methods and their consequences, whether beneficial or adverse, on drug interactions can pose health hazards in certain cases. Recognizing this knowledge gap underscores the urgency for intensified and targeted scientific inquiry into the multitude of conceivable interactions among food composition, processing methods, and pharmaceutical agents. A thorough investigation into the underlying mechanisms is imperative. The complexity of this field requires substantial scrutiny and collaborative efforts across diverse domains, including medicine, pharmacology, nutrition, food science, food technology, and food engineering.

Effect of PEF Treatment on Chosen Properties of Raw and Hot Air- and Freeze-Dried Poultry Meat

The properties of fresh meat, such as high water activity, a slightly acidic reaction, and the availability of carbohydrates and proteins, make it a microbiologically unstable and easily perishable raw material. One of the oldest food preservation techniques is drying. Furthermore, non-thermal food processing techniques such as pulse electric field (PEF) treatment can be used to support the drying process and change the properties of the obtained product. Thus, this study aimed to analyze the impact of pulsed electric field treatment on the hot air-drying and freeze-drying of poultry meat as well as on the quality of the dried meat. The PEF pretreatment and drying methods significantly altered the physical characteristics of the poultry meat. The PEF treatment enhanced the efficiency of freeze-drying by electroporation, reducing drying time and shrinkage. However, in the hot air-drying, the PEF-treated samples prolonged drying, potentially due to muscle structure damage and increased shrinkage. The pretreatment techniques affected the structure of the meat and positively influenced the higher porosity and lower shrinkage. Also, drying decreased the water activity and increased the dry matter content, which ensured the safety of the final product. The freeze-dried material exhibited a higher rehydration rate, improved hygroscopic properties, and better meat color compared to the hot air-dried material. Nevertheless, the selection of the process parameters, for both the pretreatment and drying process, is crucial to ensure a high quality of the dried meat product and should be selected carefully in order to guarantee that the highest quality of the dried product is obtained.

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 functionaland 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.

Research advances on the effects of thermal and non-thermal processing techniques on the physicochemical properties and microbiological control of liquid eggs

Research advances on the effects of thermal and non-thermal processing techniques on the physicochemical properties and microbiological control of liquid eggs

Ultrasound-Assisted Enzymatic Protein Hydrolysis in Food Processing: Mechanism and Parameters.

Ultrasound has been widely used as a green and efficient non-thermal processing technique to assist with enzymatic hydrolysis. Compared with traditional enzymatic hydrolysis, ultrasonic-pretreatment-assisted enzymatic hydrolysis can significantly improve the efficiency of enzymatic hydrolysis and enhance the biological activity of substrates. At present, this technology is mainly used for the extraction of bioactive substances and the degradation of biological macromolecules. This review is focused on the mechanism of enzymatic hydrolysis assisted by ultrasonic pretreatment, including the effects of ultrasonic pretreatment on the enzyme structure, substrate structure, enzymatic hydrolysis kinetics, and thermodynamics and the effects of the ultrasonic conditions on the enzymatic hydrolysis results. The development status of ultrasonic devices and the application of ultrasonic-assisted enzymatic hydrolysis in the food industry are briefly described in this study. In the future, more attention should be paid to research on ultrasound-assisted enzymatic hydrolysis devices to promote the expansion of production and improve production efficiency.

Structure optimization of pulsed electric field processor and its sterilization effect

Abstract Pulsed electric field (PEF) technology is a highly promising non-thermal processing technique, which holds great potential for sterilizing liquid food. The effectiveness of this treatment depends on two crucial factors: pulse parameters and the structure of the processor. In this study, we focus on optimizing the shape of insulators within the PEF processor to improve the sterilization effect. This research provides a reliable technical reference for designing industrial equipment. The numerical simulation of multi-physics fields was employed to analyze the temperature, electric field, and fluid field distributions for different insulators. Ultimately, the geometric structure of the insulator was optimized by embedding a 0.7-mm arc. Sterilization experiments were then conducted on Escherichia coli and Staphylococcus aureus suspensions with conductivities similar to those of real grapefruit juice. The sterilization effect of the processor with the optimized structure and the maximum applied voltage was examined at the same driving frequency. The results indicate that compared to the original structure, there is an increase in withstanding voltage by 5–10 kV while maintaining significantly improved bactericidal effects at the same applied voltage. Furthermore, we preliminarily discussed the sterilization mechanism by combining electroporation theory with the electroporation threshold of S. aureus.

Cold plasma as an emerging nonthermal technology for food processing: A comprehensive review

Cold plasma, a partially ionized gas maintained at low temperatures, has emerged as a promising nonthermal food processing technique with various applications, including food sterilization and improved agricultural output. By generating reactive species such as ions, radicals, and photons, cold plasma interacts with and modifies the surfaces of materials or living cells. This comprehensive review focuses on the microbial decontamination capabilities of cold plasma and its impact on a wide range of food products, including cereals, milk, fruits, vegetables, and meat. Cold plasma treatment offers distinct advantages over traditional methods such as heat treatment, chemical treatment, and irradiation. It effectively eliminates pathogenic microbes from food surfaces while preserving the quality, flavor, and nutritional content of the food. By sterilizing food surfaces and packaging materials, cold plasma significantly reduces the risk of harmful microorganism contamination. Moreover, it extends the shelf life of food products by eliminating germs, viruses, and other hazardous microbes. This review critically assesses the qualitative impact of plasma treatment, emphasizing the importance of selecting the appropriate cold plasma technology for various food products. To ensure the safety and effectiveness of cold plasma technology for commercial implementation, this review investigates the properties of cold plasma treatment for different food products. It examines the molecular connections between dietary components and cold plasma species, highlighting potential avenues for future research.

Non-thermal processing of milk: Principles, mechanisms and effect on milk components

The conventional thermal treatment causes chemical modifications to milk constituents such as protein denaturation, loss of vitamins and flavoring compounds, depression at freezing point, and nonenzymatic browning, which may result in adverse changes to the flavor, color, and nutritional value of milk. This review looks into the emerging non-thermal processing techniques such as high-pressure processing (HPP), pulsed electric field (PEF), ultrasonication and hydrodynamic, UV-irradiation and plasma technology, cavitation, and their effects on milk components and bioactive compounds. For consumer acceptability and safety, simultaneous and crucial needs exist: microbial safety, fresh like quality and preservation of bioactive compounds. Technologies like HPP and PEF have been capable of achieving microbial reduction with moderate thermal inputs. Ultrasonication and hydrodynamic cavitation have the dual functions of deactivating microorganisms and homogenizing, and plasma and UV-C radiation could ensure minimal loss of heat-sensitive components. These processing techniques could be an alternative to pasteurization and sterilization of milk with assured microbial inactivation and maximal retention of nutrients in dairy.

Application of different orifices for hydrodynamic cavitational effects on deactivation of Escherichia coli and Staphylococcus aureus in milk

Thermal processing reduces the nutritional value and flavour of milk due to the application of heat, although it has the benefits for safety and shelf life by eliminating microbes. Also, the growing preference of consumers for natural and minimally processed foods has led to an increase in the use of nonthermal milk processing techniques. Hydrodynamic processing (HC) is one such recent, inventive, scalable, and economically favourable nonthermal technique. Thus, the influence of hydrodynamic cavitation on the deactivation of Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria was investigated using four different orifice plates: ORFP 1 (Ø=4 mm); ORFP 2 (Ø=3 mm); ORFP 3 (Ø=2.27, 3 holes), and ORFP 4 (Ø=2 mm, 5 holes). Milk with cell inoculum was treated at three different pressures (3, 5 and 7 bar) and six different treatment time (5, 10, 15, 20, 30 and 40 min). Multi-hole orifices with higher α-value (plate parameter) were more effective in deactivation of microbial population in comparison to single hole orifices. Multi-hole orifice (ORFP 4) had the highest reduction of microbial cells, with 3.5 and 2.83 Log reduction for E. coli and S. aureus, respectively followed by ORFP 3, ORFP 2, and ORFP 1. Cavitation number in the range of 0.21–0.66 resulted in significant reduction of E. coli and S. aureus. From this study, it can be said that both flow geometry (α, β and flow area) of orifice plates and flow characteristics (flow rate and cavitation number) of the hydrodynamic cavitation system had an impact on the reduction of bacteria. Thus, hydrodynamic cavitation with different configuration of orifice plates can offer a potential option for thermal pasteurization.

Simulation of High-voltage Pulse Generator for Environment-friendly, Non-thermal Pasteurization Applications

Nowadays, the demand for high-voltage pulse generators has begun to proliferate in many industries. Particularly in the food processing industries, the conventional method of pasteurization involves the use of heat treatment processes, which are not environment-friendly; hence, researchers are working towards environment-friendly, non-thermal food processing techniques by which the microorganisms present in the liquid food can be eliminated. High-voltage pulsed electric field technology is one of the popular non-thermal food processing techniques. Recent advancements in power electronic switching technology have facilitated the development of solid-state pulse generators for these applications. In this paper, the simulation of a high-voltage pulse generator for eco-friendly pasteurization applications has been attempted using a cascaded boost converter topology. The entire simulation is carried out using MATLAB/Simulink software. The designed two-stage cascaded boost converter is tested for varying duty cycles and loads. The results with resistive and inductive loads have been analyzed.

Effect of electron beam irradiation on the quality of vacuum-packed, chilled-stored tilapia fish chunks

Currently, there is an increasing demand for minimally processed or convenience food products without any quality loss. Electron Beam Irradiation (EBI) is a non-thermal processing technique used to preserve the nutrient value and shelf-life extension of food products. In the present study, the effect of electron beam irradiation on the quality of tilapia fish chunks was evaluated. Tilapia fish chunks were vacuum packed and exposed to 0, 2.0, and 4.0 kGy doses of electron beam irradiation and kept under chilled storage. Biochemical, microbiological, and sensory qualities were analysed for up to 41 days. pH (6.85 to 7.10), total volatile base nitrogen (TVB-N), peroxide value (PV) and thiobarbituric acid (TBA) content showed an increasing trend during storage. It was observed that TVB-N content was lower in the irradiated sample than control. Thiobarbituric acid reactive substances (TBARS) values were within the acceptable limits during storage. Microbiological analysis revealed that irradiated fish chunks had lower total plate count, Pseudomonas count and Brochothrix thermosphacta count compared to the control. The hydrogen sulfide formers count and Lactobacillus count were nil in the irradiated fish chunks. In terms of microbial and sensory qualities, it was found that electron beam irradiated samples had an extended shelf-life of 28-38 days (with respect to dose level), compared to the control which had a shelf-life of only 16 days. Keywords: Non-thermal processing, Peroxide value, Sensory qualities, Shelf-life, TBA, TBARS, TVB-N, Vacuum packing

Effect of atmospheric cold plasma treatment on acid gelation properties of skim milk: Rheology and textural studies

Cold plasma processing is a non-thermal food processing technique that has been shown to improve the gelling properties of plant proteins by altering their structure through oxidation and crosslinking. This study aimed to investigate the effects of cold plasma treatment on the rheological properties of skim milk under different conditions, focusing on the impact of feed gas and treatment time on skim milk's sulfhydryl content, flow properties, and acid gelling behavior. Results showed that free sulfhydryl content decreased with treatment time, with a notable reduction observed after 2 min of N2-O2 plasma treatment. Skim milk treated with N2 plasma experienced a more gradual decrease in free SH content. Cold plasma increased skim milk viscosity over time. N2-O2 plasma treatment significantly affected G′40 and G′4 storage moduli, with an increase observed after 2 min of exposure but no change beyond that time. Acid gels' greenness (a* value) decreased with increasing treatment time compared to the control. Acid gel firmness of milk treated with N2-O2 plasma for 1 min significantly increased from 1.804 N to 1.912 N, and further to 2.072 N after 2 min of treatment. However, longer exposure times led to lower firmness in gels. N2 plasma treatment also significantly impacted acid gel firmness. Syneresis in acid gels decreased from 63.4 % to 57.7 % and 58.7 % after 1 and 2 min of N2-O2 plasma treatment, respectively, but increased to about 70 % after 4 min. Acid gels made from milk treated with N2 plasma experienced considerably less syneresis. The cold plasma treatment under different conditions significantly affected the properties of skim milk, with various impacts on sulfhydryl content, flow properties, and acid gelling behavior. These findings demonstrate the potential applications of cold plasma processing in the food industry to improve product properties.

Effects of ultrasound on the oxidation and structures of the myofibrillar protein in the presence or absence of soybean oil.

Ultrasound is widely used as a novel non-thermal processing technique to improve protein properties. In recent decades, applying ultrasound-assisted emulsification (UAE) to produce protein-stabilized emulsion has attracted people's attention. Instead of applying ultrasound to treat a single protein solution, UAE treatment refers to the use of sonication to a mixture of protein and oil. The purpose of this study was to compare the different effects of ultrasound treatment on the properties of the myofibrillar protein (MP) in the presence or absence of soybean oil. A suitable sonication power was selected based on the change in emulsion properties. The 300W sonication power was selected due to its most effectively decreased emulsion droplet size and increased absolute zeta potential. Sonication more significantly increased the protein carbonyl content and disulfide bonds of the MP-soybean oil sample than MP sample. Due to the existence of oil, ultrasound could unfold more protein molecules illustrated by a lower α-helix content and intrinsic fluorescence intensity, and a higher surface hydrophobicity. LC-MS/MS results illustrated that sonication enhanced the myosin heavy chain and actin content at the soybean oil interface as well as accelerated the myosin light chain to separate from myosin in the MP-soybean oil system. In summary, ultrasound treatment could lead to a higher level of protein oxidation and more protein molecule exposure in the MP with the presence of oil system than in the oil-free MP system. This article is protected by copyright. All rights reserved.

High-pressure homogenization treatment of red seaweed Bangia fusco-purpurea affects the physicochemical, functional properties and enhances in vitro anti-glycation activity of its dietary fibers

In this study, high-pressure homogenization (HPH) technique was applied for the pretreatment of Bangia fusco-purpurea, and the effect of HPH on the composition, physiochemical and functional properties, and in vitro anti-glycation activity of dietary fiber from this seaweed (B. fusco-purpurea dietary fiber, BDF) was studied. Results showed that HPH significantly increased water-soluble dietary fiber (SDF) content in BDF. Water-holding capacity, oil-holding capacity, and glucose delay dialysis index of BDF were significantly enhanced after HPH treatment. Additionally, HPH significantly improved the in vitro anti-glycation activity of BDF by inhibiting the formation of advanced glycation end products (AGEs) and mitigating damage induced by AGEs on intestinal cells. These improvements could be attributed to the formation of the coarse and porous structure and greater exposure of hydroxyl groups of BDF caused by HPH treatment. These results implied the potential of HPH in seaweed processing and provided a scientific basis for the in-depth, comprehensive utilization of B. fusco-purpurea. Industrial relevanceHPH is an emerging non-thermal food processing technique with promising application potential in food industry. In this study, we found that HPH technique could significantly change the composition, improve physiochemical and functional properties and enhance anti-glycation activity of dietary fiber from seaweed B. fusco-purpurea. Our results validated the efficiency of HPH on dietary fiber modification, implying the potential of HPH in food industry and healthy industry.

Combining Non-Thermal Processing Techniques with Edible Coating Materials: An Innovative Approach to Food Preservation

Innovative processing and packaging technologies are required to create the next generation of high-quality, healthy, safe, and sustainable food products. In this review, we overview the potential of combining edible coating materials with non-thermal processing technologies to improve the quality, increase the safety, extend the shelf life, and reduce the waste of foods and plastics. Edible coatings are typically assembled from food-grade structuring ingredients that can provide the required mechanical and barrier properties, such as proteins, polysaccharides, and/or lipids. These materials can be fortified with functional additives to further improve the quality, safety, and shelf life of coated foods by reducing ripening, gas exchange, and decay caused by bacteria and fungi. Non-thermal processing techniques include high hydrostatic pressure, pulsed light, ultrasound, and radiation technologies. These technologies can be used to inhibit the growth of pathogenic or spoilage microorganisms on packaged foods. Examples of the application of this combined approach to a range of highly perishable foods are given. In addition, the impact of these combined methods on the quality attributes of these food products is discussed.

Biotransformation of ginsenosides from Korean wild-simulated ginseng (Panax ginseng C. A. Mey.) using the combination of high hydrostatic pressure, enzymatic hydrolysis, and sonication

High hydrostatic pressure is a non-thermal processing technique for extracting functional compounds from herbal plants. This study aims to investigate the effectiveness of the combination of high hydrostatic pressure (HHP), enzymatic hydrolysis, and sonication for extracting wild-simulated ginseng (WSG) to improve yields of major and minor ginsenosides. By using LC-MS/MS analysis, the total ginsenoside yield was enhanced by 25.62% by increasing the pressure of HHP and sonication treatment (HHP-soni) extraction from 100 to 300 MPa. Furthermore, compared to HHP-soni at 100 MPa, adding two commercial food-grade enzymes (Viscozyme and Pectinex) resulted in a 1.23–1.43-fold increase in total ginsenoside contents, as well as a 1.09–1.95-fold increase in the contents of seven major ginsenosides. Similarly, HHP-soni with enzymes increased the yields of five minor ginsenosides (Ro, Rh1, F2, CO, and Rg3) by 1.76–30.24 times compared to extraction with Pectinex at 0.1 MPa. Ginsenoside compound K and protopanaxadiol were detected after extraction using Pectinex with HHP-soni, but not after extraction using Pectinex and sonication at 0.1 MPa. While the contents of the stereoisomers 20(S)-Rg3 and 20(R)-Rg3 were similar after extraction at pressures of 100 and 200 MPa, the 20(S)-Rg3 content was 1.87 times higher than the 20(R)-Rg3 content after HHP treatment at 300 MPa. From the analytical data, we inferred the hydrolytic pathways of the major to minor ginsenosides, and specifically the ginsenoside Rb1 standard, when using Pectinex under experimental conditions. These findings suggest that the combination process of HHP, sonication, and Pectinex treatment could improve the quality of WSG.