Non-thermal Processing Technique Research Articles

Cold plasma technology: does it have a place in food processing?

In recent years, there has been a growing demand for alternative food processing technologies that can improve food safety while preserving the nutritional quality of food products. Traditional thermal processing methods can lead to nutrient loss and degradation, prompting the exploration of novel approaches. Cold plasma (CP) technology, an emerging non-thermal food processing technique, has gained significant attention for its potential in the food industry. We provide herein, an introduction to CP and an overview of the technology, highlighting its potential advantages in safety, efficiency, and environmental friendliness.

Cold plasma processing of kiwifruit juice: Effect on physicochemical, nutritional, microstructure, rheological properties and sensory attributes.

This study aimed to compare the untreated, cold plasma (CP)-optimized (30 kV/5 mm/6.7 min), CP-extreme (30 kV/2 mm/10 min), and thermally treated (TT) (90 ℃/5 min) kiwifruit juices based on the physicochemical (pH, total soluble solids (TSS), titratable acidity (TA), total color change (ΔE)), physical (particle size and rheology), microstructure (optical microscope), bioactive compounds (polyphenol, ascorbic acid, and sugar compounds), and sensory characteristics of kiwifruit juice. The pH, TSS, and TA were not significantly affected in CP and TT juice, whereas the ΔE (6.52) of TT juice lies in the range of "greatly visible." The microstructure characteristics of juice significantly changed after CP and thermal treatment. The cell and tissue disruption in CP-extreme and thermally treated juice was more than CP-optimized. The particle size of juice decreased irrespective of treatment, but the span value of CP-optimized juice was the lowest. Further, the CP treatment showed a lower consistency index, apparent viscosity, and pseudoplasticity of juice than the thermal treatment. The CP-treated juice retained bioactive and nutritional attributes more than thermally treated juice. The CP-optimized, CP-extreme, and thermal treatment reduced the sucrose content by 54, 55, and 23%, while the fructose and glucose content were increased by 17, 12, & 93%, and 17, 11 & 99%, respectively. Among the CP-treated juice, CP-optimized (71.36 mg/100g) contained a higher amount of ascorbic acid than the CP-extreme (64.36 mg/100g). Based on the similarity values in the fuzzy logic analysis, the sensory attributes of CP-optimized treated juice were superior to CP-extreme and thermal treated. PRACTICAL APPLICATION: In this era, non-thermal processing techniques are trending for retaining the nutrition and stability of juice. The old plasma (CP)-treated kiwifruit juice had better nutritional, bioactive compounds, and sensory attributes than the thermally treated juice. Further, the CP-treated juice had higher flowability and lower viscosity, making it ideal for juice processing. The conclusions drawn suggest that CP processing is a better alternative for processing kiwifruit juice than thermal processing.

A review on advancements in emerging processing of whey protein: Enhancing functional and nutritional properties for functional food applications

AbstractWhey protein (WP) isolates are widely used in food products because they improve protein content, functional properties, and health benefits. It has been observed that WP can form conjugates with essential micronutrients, improving their dietary delivery and biological availability. WP and its derived bioactive peptides have potential health benefits in preventing chronic diseases. However, the off‐flavor and bitter peptides of WP are limiting factors that can be used in the food and beverage industries. Emerging innovative processing technologies, such as high hydrostatic pressure, ultrasonication, and extrusion, improve WP gelling ability, gel strength, and storage stability, providing high‐quality and healthy functional products. The integration of technological advancements into WP‐loaded fortified food products (FFPs) has increased the uptake rate of bioactive compounds, resulting in increased bioavailability and bioaccessibility in the human body. Furthermore, WP‐based FFPs treated with advanced thermal and nonthermal processing techniques possess better rheological properties, expansion ratios, and textural properties. Therefore, WP would be a promising and sustainable ingredient for developing stable functional foods. This review explores recent advancements in the processing technologies of WP, emphasizing their role in enhancing its bioavailability and functional properties for different food applications.

Advances in Non-thermal Food Processing Methods-Principle Advantages and Limitations for the Establishment of Minimal Food Quality as well as Safety Issues: A Review

Background: The demand from consumers for safe, healthy food with a long shelf life, with no change in taste or nutritive value, has made food safety a key concern in today's world. Traditional thermal food processing technology has trouble meeting these standards. Conventional thermal and non-thermal processing has limitations and to overcome these limitations more studies are conducted regarding the novel non-thermal food processing methods. Objective: The goal of this paper was to present an overview of the research on the development of non-thermal processing techniques, such as electrofreezing, high hydrostatic pressure, pulsed electric fields, ultrasound, pulsed light, and plasma activated water, as well as their advantages and limitations. Methods: The present review aims to summarize findings related to novel non-thermal processing techniques, gathered from work published in scientific journals, related books, and book chapters from sources such as Web of Science (WoS), Google Scholar, Scopus and ScienceDirect. Results: Non-thermal treatment may result in more desirable outcomes, such as greater preservation of heat-sensitive nutrients, fewer changes in sensorial as well as physico-chemical quality of the processed foods. Conclusion: Compared to traditional heat processing, the nutritional value of foods is better preserved, and the sensory qualities of foods are less altered. These novel techniques can be combined with each other to achieve higher efficiency and overcome other limitations. More studies should be conducted regarding the combination of novel non-thermal techniques to achieve greater efficiency.

A review study on the effects of thermal and non-thermal processing techniques on the sensory properties of fruit juices and beverages

A review study on the effects of thermal and non-thermal processing techniques on the sensory properties of fruit juices and beverages

The Cashew Pseudofruit (Anacardium occidentale): Composition, Processing Effects on Bioactive Compounds and Potential Benefits for Human Health.

The fruit of the cashew, a tree belonging to the family Anacardiaceae, is composed of approximately 10% nut (cashew) and 90% stalk or pseudofruit, usually discarded in situ and fermented in the soil. This review identifies cashew pseudofruit's physicochemical characteristics and bioactive compounds and their possible relationship to health benefits. Different processing techniques have been used to preserve the pseudofruit, and the effect of these techniques on its nutrients is also reviewed in this work. Cashew is a highly perishable product with moisture content above 80% w/w and 10% w/w sugars. It also has a high content of polyphenols, flavonoids, and tannins and high antioxidant properties that are best preserved by nonthermal processing techniques. The pseudofruit presents the high inhibitory activity of α-amylase and lipase enzymes, has anti-inflammatory and body weight reduction properties and healing activity, and controls glucose levels, insulinemia, and insulin resistance. For all these reasons, cashews have been promoted as a propitious food/ingredient for preventive and therapeutic management of different pathologies such as diabetes, dyslipidemia, obesity, hypertension, fatty liver, and acne. Moreover, it has positive effects on the intestinal microflora, among others. This pseudofruit has a high potential for the development of functional foods.

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.

Pretreatment and Non-thermal Processing Technologies for Quality Maintenance and Shelf-life Extension of Seafoods

The seafood industry faces significant challenges in preserving the quality and extending the shelf-life of its products to meet the demands of consumers for fresh, safe, and nutritious seafood. Apart from traditional pretreatments such as washing, sorting, and deheading, several emerging technologies like ozonized water (OW), acidic electrolyzed water (AEW), and plasma-activated water (PAW) have drawn attention for seafood industry. These innovative technologies not only improve quality of seafood but also effectively reduce contaminated microorganisms and enzymatic activity, thereby delaying spoilage. Furthermore, non-thermal processing technologies, including high pressure processing (HPP), cold plasma (CP) treatment, and modified atmosphere packaging (MAP), offer promising alternatives to conventional heat-based processes. These technologies are characterized by their ability to inactivate microorganisms and enzymes, while preserving the sensory attributes and nutritional value of seafood. HPP and MAP particularly have demonstrated their profound ability to extend the shelf-life of seafood products without compromising their quality or sensorial attributes. Furthermore, the synergistic effects of combining pretreatment and non-thermal processing techniques, have potential to prolong shelf-life and improve safety of seafood products. Thus, the integration of these pretreatments and technologies offers a promising avenue for enhancing the quality and safety of seafood products.

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.