The effects of cold plasma technology on physical, nutritional, and sensory properties of milk and milk products

Emerging Technologies for Improving Properties, Shelf Life, and Analysis of Dairy Products

Processing results in several kinds of dairy products with variable properties and shelf lives that preserve and often enhance the unique nutritional and biological value of milk [...].

Coconut milk treated by atmospheric cold plasma: Effect on quality and stability

Commercial sterilization plays an important role in extending the shelf-life of coconut milk. However, thermal sterilization affects the quality of coconut milk. This study was initiated to evaluate the effects of atmospheric cold plasma (ACP) treatment on some important quality parameters of coconut milk. ACP treatment had a slight effect on physicochemical characteristics and nutritional ingredients while it obviously reduced the colony count. Furthermore, ACP treatment obviously promoted the formation of lactone, an indispensable volatile substance in coconut milk. Insufficient or moderate ACP treatment had subtle effect on the sensory quality. Notably, moderate ACP treatment reduced the droplet size from 28.0 μm to 18.6 μm, and improved the stability during storage and centrifugation, especially at 60 kV 60 s. Overall, sterilization of coconut milk by ACP at 60 kV 60 s was the most ideal. This study can provide theoretical guidance for the application of ACP in liquid food.

Influence of cold atmospheric pressure plasma treatment of Spirulina platensis slurry over biomass characteristics

Cold atmospheric pressure plasma (CAPP) technique is an innovative non-thermal approach for food preservation and decontamination. This study aimed to evaluate the effect of CAPP power density on microorganism inactivation and quality of Spirulina platensis (S. platensis) slurry. 91.31 ± 1.61% of microorganism were inactivated within 2.02 ± 0.11 min by 26.67 W/g CAPP treatment under 50 ℃. Total phenolic, Chlorophyll-a (Chl-a), and carotenoids contents were increased by 20.51%, 63.55%, and 70.04% after 20.00 W/g CAPP treatment. Phycobiliproteins (PBPs), protein, intracellular polysaccharide, and moisture content of S. platensis was decreased, while vividness, lightness, color of yellow and green, antioxidant activity, Essential Amino Acid Index were enhanced after CAPP treatment. The nutrient release and filaments breakage of CAPP-treated S. platensis improved its bio-accessibility. The findings provided a deep understanding and insight into the influence of CAPP treatment on S. platensis, which were meaningful for optimizing its sterilization and drying processing condition.

Impact of Nonthermal Plasma on Lipid Oxidation from the Perspective of Plasma Treatment Parameters and Plasma Species: Identification of Key Reactive Species

Nonthermal plasma is a mild processing technology for food preservation. Its impact on lipid oxidation was investigated in this study. Stripped methylesters were considered as a basic lipid model system and were treated by a multihollow surface dielectric barrier discharge. In dry air plasma, O3, ·NO2, ·NO3, and 1O2 were identified as the main reactive species reaching the sample surface. Treatment time was the most prominent parameter affecting lipid oxidation, followed by the (specific) power input and the plasma-sample distance. In humid air plasma, less O3 was detected, but ONOOH and O2NOOH were generated and presumed to play a role in lipid oxidation. Ozone mainly resulted in the formation of carbonyl substances via the trioxolane pathway, while reactive nitrogen species (i.e., ·NO2, ·NO3, ONOOH, and O2NOOH) led to the formation of hydroperoxides. The impact of short-living radicals (e.g., ·O, ·N, ·OH, and ·OOH) was restricted in general, since they dissipated too fast to reach the sample.·NO, HNO3, H2O2, and UV radiation did not induce lipid oxidation. All the reactive species identified in this study were associated with the presence of O2 in the input gas.

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.

Alleviating Heavy Metal Toxicity in Milk and Water through a Synergistic Approach of Absorption Technique and High Voltage Atmospheric Cold Plasma and Probable Rheological Changes

In this study, we combined atmospheric pressure cold plasma, a novel treatment technology, with an absorption technique with soybean husk to remove Pb and Cd from milk. Different combinations of treatment duration, voltage, and post treatment retention time were used to determine the effectiveness of cold plasma. Soybean husk was used for metal extraction, and it was observed that when the milk samples were plasma treated with a discharge voltage of 50 kV for 2 min and held for 24 h, the highest mean elimination of about 27.37% for Pb and 14.89% for Cd was obtained. Reactive oxygen and nitrogen species produced from plasma treatment were identified using Optical Emission Spectra analysis. A high voltage of 50 kV plasma for a 2 min duration could produce 500 ± 100 ppm of ozone concentration inside the treated package. The value of ΔE, which indicates overall color difference measurement, was significantly (p < 0.05) higher in all the treated samples than control samples. However, in the frequency range from 0.01 to 100 Hz, there was not much difference between the control and treated sample in the frequency sweep test. The identified functional groups at different wavenumbers (cm−1) in the treated samples were found to be similar compared to the control samples.

Effect of the Application of Cold Plasma Energy on the Inactivation of Microorganisms, Proteins, and Lipids Deterioration in Adobera Cheese

Cheeses are perishable foods that must fulfill sanitary and quality requirements according to the parameters established globally. Plasma as a nonthermal inactivation technique has been a current research topic for food preservation, so the objective of this work was to study the effect of plasma energy against microorganisms in Adobera cheese (traditional Mexican cheese) as well as evaluate the possible degradation of lipids and protein. 108 CFU/mL of Escherichia coli ATCC 25922, Salmonella ATCC13076, and Staphylococcus aureus ATCC 6538 were inoculated at 0.5 g of Adobera cheese and were subjected to an energy of 30 volts, in a dielectric barrier discharge reactor (DBDR) at intervals of times 1, 3, 5, 7, 10, and 15 min. A flow of a mixture of air and helium at 96% purity was used. The decimal reduction time (D) was determined, and the oxidation of proteins and lipids was analyzed after each treatment. The results showed an annihilating effect of plasma on the indicator bacteria under study, and a reduction of 5 logarithmic cycles was obtained. The maximum degree of lipid oxidation was 23 acid degree values (ADV) after 7 min of exposure to plasma. The oxidation of proteins showed a direct and proportional relationship between the formation of carbonyl groups with the percentage significant loss to the concentration of carbonyl groups with the concentration of protein oxidation, after 3 min of exposure to cold plasma levels of 82% and 99% oxidation of Adobera cheese protein and free casein, respectively. We conclude that the plasma energy applied to Adobera cheese is an effective treatment to inactivate bacteria. However, there is the possibility of causing changes in taste and odor, due to the release of fatty acids and the oxidation of proteins.