Investigation of decontamination effect of argon cold plasma on physicochemical and sensory properties of almond slices

Chemical and physical changes induced by cold plasma treatment of foods: A critical review

Cold plasma treatment is an innovative technology in the food processing and preservation sectors. It is primarily employed to deactivate microorganisms and enzymes without heat and chemical additives; hence, it is often termed a "clean and green" technology. However, food quality and safety challenges may arise during cold plasma processing due to potential chemical interactions between the plasma reactive species and food components. This review aims to consolidate and discuss data on the impact of cold plasma on the chemical constituents and physical and functional properties of major food products, including dairy, meat, nuts, fruits, vegetables, and grains. We emphasize how cold plasma induces chemical modification of key food components, such as water, proteins, lipids, carbohydrates, vitamins, polyphenols, and volatile organic compounds. Additionally, we discuss changes in color, pH, and organoleptic properties induced by cold plasma treatment and their correlation with chemical modification. Current studies demonstrate that reactive oxygen and nitrogen species in cold plasma oxidize proteins, lipids, and bioactive compounds upon direct contact with the food matrix. Reductions in nutrients and bioactive compounds, including polyunsaturated fatty acids, sugars, polyphenols, and vitamins, have been observed in dairy products, vegetables, fruits, and beverages following cold plasma treatment. Furthermore, structural alterations and the generation of volatile and non-volatile oxidation products were observed, impacting the color, flavor, and texture of food products. However, the effects on dry foods, such as seeds and nuts, are comparatively less pronounced. Overall, this review highlights the drawbacks, challenges, and opportunities associated with cold plasma treatment in food processing.

The impact of cold plasma innovative technology on quality and safety of refrigerated hamburger: Analysis of microbial safety and physicochemical properties

Atmospheric cold plasma (ACP) is an innovative non-thermal decontamination technology that is considered a great alternative to conventional preservation methods. Most importantly, improving microbial safety along with maintaining the sensory and quality properties of the treated foods, especially for perishable products. Hence, this study aimed to investigate the antimicrobial effects of novel dielectric barrier discharge (DBD) and Jet cold plasma systems and their impact on the physicochemical, color, and sensory properties of refrigerated hamburger samples. In the current study, hamburger samples were inoculated with Staphylococcus aureus, Escherichia coli, Molds and Yeasts microbial suspension (~10⁶ CFU/mL), and then were treated with argon (Ar), helium (He), nitrogen (N), and atmosphere (Atm) gases at different times (s) (0, 30, 60, 90, 180, 360). Similarly, uninoculated samples were considered for total viable count (TVC) testing. The results exhibited that plasma system type, gas type, and treatment time had a significant antimicrobial effect with a microbial reduction ranging from 0.01 to 2 log CFU/g and 0.04-1.5 log CFU/g for DBD and Jet plasma systems, respectively. Also, a treatment time longer than 90 s for DBD and 180 s for jet resulted in a significant reduction in microbial count. The ability of atmospheric cold plasma to inactivate tested foodborne pathogenic bacteria (E. coli and S. aureus) was stronger than other gases because the concentration of O₃ and NO gases in atmospheric plasma is higher than other used plasma gases. Surface color measurements (L*, a* and b*) of samples in both methods (DBD and Jet) were not significantly affected. Moreover, samples treated with various plasma gases have indicated insignificant oxidation changes (Thiobarbituric acid assay). These outcomes can assist to reduce microbial contamination and oxidation of hamburgers as a high-consumption and perishable product using ACP technology. Owing to the non-thermal nature of ACP, samples treated with ACP have exhibited no or least effects on the physical, chemical, and sensory features of various food products. As a result, cold plasma innovative technology can be proposed and used as an efficient preservative method to increase the shelf life of food products.

The use of cold plasma technology in solving the mold problem in Kashar cheese

In this study, the possibilities of using cold plasma technology in solving the mold problem, which is one of the most important problems in Kashar cheese, were investigated. For this purpose Kashar cheeses were exposed to cold plasma with different gas compositions. As a result of the study 3-4 log reduction was achieved for both Aspergillus flavus and Penicillium crysogenum. The pH and aw values of samples were decreased with cold plasma application. The b* values of samples increased while L* and a* values decreased. When all the results obtained are considered as a whole, it can be said that cold plasma technology improves the physicochemical properties of Kashar cheese and provides significant decrease in mold count of the product.

Impact of Non-Thermal Technologies on the Quality of Nuts: A Review

Nuts are widely consumed worldwide, mainly due to their characteristic flavor and texture, ease of consumption, and their functional properties. In addition, consumers increasingly demand natural or slightly processed foods with high quality. Consequently, non-thermal treatments are a viable alternative to thermal treatments used to guarantee safety and long shelf life, which produce undesirable changes that affect the sensory quality of nuts. Non-thermal treatments can achieve results similar to those of the traditional (thermal) ones in terms of food safety, while ensuring minimal loss of bioactive compounds and sensory properties, thus obtaining a product as similar as possible to the fresh one. This article focuses on a review of the main non-thermal treatments currently available for nuts (cold plasma, high pressure, irradiation, pulsed electric field, pulsed light, ultrasound and ultraviolet light) in relation to their effects on the quality and safety of nuts. All the treatments studied have shown promise with regard to the inhibition of the main microorganisms affecting nuts (e.g., Aspergillus, Salmonella, and E. coli). Furthermore, by optimizing the treatment, it is possible to maintain the organoleptic and functional properties of these products.

Effects of glycerol and sorbitol on a novel biodegradable edible film based on Malva sylvestris flower gum

There has been an increasing interest in the investigation of novel eco-friendly packaging materials. An edible film based on Malva sylvestris flower gum was fabricated with 40%, 50%, and 60% glycerol and sorbitol using casting method. FTIR analysis was applied to identify the functional groups of films with different concentrations of plasticizers. The lightness of the samples did not affect upon increasing the sorbitol and glycerol; nevertheless, the samples tended to be green and yellow. SEM images indicated that glycerol-based films enjoy heterogeneous and porous surfaces compared to the sorbitol-based samples. Although Tensile Strength and Young's Modulus characteristics declined considerably (p < .05) upon plasticizer addition, elongation at break increased by more than 10% in glycerol-based samples. A significant (p < .05) decrement was observed in the density of film strips via the addition of glycerol and sorbitol. Moisture content of films incorporated with both plasticizers saw a considerable improvement (p < .05) upon increasing the plasticizer concentration from 40% to 60% and is ascribed to the water-holding capacity of plasticizers. Water contact angle and water solubility increased via plasticizer supplementation, which is attributed to the hydrophilic characteristic of glycerol and sorbitol, are in line with SEM analysis.

Investigation of the Composition, Antimicrobial, Antioxidant, and Cytotoxicity Properties of Salvia abrotanoides Essential Oil

Medicinal plants present promising attributes in traditional medicine based on earlier published documents. Most of the essential oils derived from vascular plants display a significant role in dealing with microbial and inflammation infections. This research aimed to provide informative knowledge about the composition, antimicrobial, and anticytotoxicity of Salvia abrotanoides essential oil. In this study, the chemical composition of S. abrotanoides was determined using FTIR and GC-MS analysis which demonstrated the significant number of monoterpenes in the constitutes. The antimicrobial activity of EO demonstrated a dose-related effect on several pathogenic bacteria and fungi; among bacteria, Gram-positive bacteria exhibited more sensitivity to the essential oil antimicrobial compounds. On the other hand, S. abrotanoides essential oil did not present antifungal activity as high as Fluconazole on Aspergillus niger and Candida albicans. The total phenolic and flavonoid content of essential oil were determined as 14.70 ± 1.4 mg·GA/g essential oil and 2.93 ± 0.41 mg Q/g essential oil, respectively. The antioxidant activity of essential oils was investigated, and it was not as high as positive controls. Moreover, the microscopic changes of S. aureus and E. coli were investigated using SEM images. The cytotoxicity potential of essential oil was evaluated on L929 and A459 cell lines and also it was estimated to be stronger on A459 cell line than that of L929.

Impacts of Cold Plasma Technology on Sensory, Nutritional and Safety Quality of Food: A Review

As an emerging non-thermal food processing technology, cold plasma (CP) technology has been widely applied in food preservation due to its high efficiency, greenness and lack of chemical residues. Recent studies have indicated that CP technology also has an impressing effect on improving food quality. This review summarized the impact of CP on the functional composition and quality characteristics of various food products. CP technology can prevent the growth of spoilage microorganisms while maintaining the physical and chemical properties of the food. It can maintain the color, flavor and texture of food. CP can cause changes in protein structure and function, lipid oxidation, vitamin and monosaccharide degradation, starch modification and the retention of phenolic substances. Additionally, it also degrades allergens and toxins in food. In this review, the effects of CP on organoleptic properties, nutrient content, safety performance for food and the factors that cause these changes were concluded. This review also highlights the current application limitations and future development directions of CP technology in the food industry. This review enables us to more comprehensively understand the impacts of CP technology on food quality and promotes the healthy application of CP technology in the food industry.

A comprehensive study on decontamination of food-borne microorganisms by cold plasma

Food-borne microorganisms are one of the biggest concern in food industry. Food-borne microorganisms such as Listeria monocytogenes, Escherichia coli, Salmonella spp., Vibrio spp., Campylobacter jejuni, Hepatitis A are commonly found in food products and can cause severe ailments in human beings. Hence, disinfection of food is performed before packaging is performed to sterilize food. Traditional methods for disinfection of microorganisms are based on chemical, thermal, radiological and physical principles. They are highly successful, but they are complex and require more time and energy to accomplish the procedure. Cold plasma is a new technique in the field of food processing. CP treatments has no or very low effect on physical, chemical and nutritional properties of food products. This paper reviews the effect of plasma processing on food products such as change in colour, texture, pH level, protein, carbohydrate, and vitamins. Cold plasma by being a versatile, effective, economical and environmentally friendly method provides unique advantages over commercial food processing technologies for disinfection of food.

Characterization of antioxidant active biopolymer bilayer film based on gelatin-frankincense incorporated with ascorbic acid and Hyssopus officinalis essential oil

In this study, a bio-based bilayer edible film based on gelatin/frankincense, with the incorporation of different concentrations of Ascorbic acid (AA) (0, 1, 2%) into the inner layer (gelatin) and Hyssopus officinalis (HO) (0, 0.75, 1.5%) essential oil in the outer layer (frankincense) was prepared. A significant increase (p < 0.05) in b* and a remarkable decrease in whiteness and lightness of the films were seen via increasing the HO ascribed to the Total Phenolic Content of HO and non-enzymatic browning. Although there was a significant decrease (p < 0.05) in Tensile Strength with the addition of HO, Elongation at Break was increased significantly as a function of HO, which is correlated with a dense and compact network in SEM images. The maximum thickness of film emulsified with 1.5%HO + 2%AA ascribed to the accumulation of solid content. The improvement in Water Contact Angle (℃) and a reduction in Water Vapor Permeability (gr/s mPa) have occurred due to the hydrophobic nature of HO.

Microbial Inactivation Property of Pulsed Corona Discharge Plasma and Its Effect on Chilled Pork Preservation

Although plasma, especially atmospheric plasma generated by corona discharge, has been proven to be effective in sterilization and food preservation, its disinfection mechanism on chilled pork is poorly understood. In this research, the bactericidal and preservation effect of corona discharge plasma (CDP) was investigated. The maximum bactericidal effect was found after 20 kV 4 kHz CDP treatment, with 2.77 log (colony-forming unit [CFU]/g), 2.41 log (CFU/g), and 1.36 log (CFU/g) reduction for Pantoea agglomerans, Serratia liquefaciens, and Kurthia zopfii, respectively, after 10 min of exposure. The efficiency of microbial inactivation was attributed to the increase of ozone, hydrogen peroxide and morphological changes. It was observed that the microbial level and total volatile binding nitrogen value of CDP-treated chilled pork samples were suppressed during storage, whereas the increase of thiobarbituric acid reactive substances value and the changes of color were still worthy of attention. The aim of this study was to explore the effect of pulsed CDP on the inactivation of spoilage microorganism inoculated on the surface of fresh pork. The prospect of this technology in meat preservation industry was also investigated.

Impacts of cold plasma treatment on physicochemical, functional, bioactive, textural, and sensory attributes of food: A comprehensive review

Cold plasma processing is a technique that uses electricity and reactive carrier gases, such as oxygen, nitrogen, or helium, to inactivate enzymes, destroy microorganisms, preserve food, and maintain quality without employing chemical antimicrobial agents.The review collates the latest information on the interaction mechanism and impact of non-thermal plasma, as an emerging processing technology, on selected physical properties, low-molecular-weight functional components, and bioactive properties of food. Significant changes observed in the physicochemical and functional properties. For example, changes in pH, total soluble solids, water and oil absorption capacities, sensory properties such as color, aroma, and texture, bioactive components (e.g., polyphenols, flavonoids, and antioxidants), and food enzymes, antinutrients, and allergens were elaborated in the present manuscript. It was highlighted that the plasma reactive species result in both constructive and antagonistic outcomes on specific food components, and the associated mechanism was different in each case. However, the design's versatility, characteristic non-thermal nature, better economic standards, and safer environmental factors offer matchless benefits for cold plasma over conventional processing methods. Even so, a thorough insight on the impact of cold plasma on functional and bioactive food constituents is still a subject of imminent research and is imperative for its broad recognition as a modern non-conventional processing technique.

Ultrasound, infrared and its assisted technology, a promising tool in physical food processing: A review of recent developments

Traditional food processing techniques can no longer meet the ever increasing demand for high quality food across the globe due to its low process efficiency, high energy consumption and low product yield. This review article is focused on the mechanism and application of Infrared (IR) and ultrasound (US) technologies in physical processing of food. We herein present the individual use of IR and US (both mono-frequency and multi-frequency levels) as well as IR and US supported with other thermal and non-thermal technologies to improve their food processing performance. IR and US are recent thermal and non-thermal technologies which have now been successfully used in food industries to solve the demerits of conventional processing technologies. These environmentally-friendly technologies are characterized by low energy consumption, reduced processing time, high mass-transfer rates, better nutrient retention, better product quality, less mechanical damage and improved shelf life. This work could be, with no doubt, useful to the scientific world and food industries by providing insights on recent advances in the use of US and IR technology, which can be applied to improve food processing technologies for better quality and safer products.