## 4 Discussion
Nevertheless, different model studies mainly use density, heat capacity and thermal conductivity of liquid egg products [26]. CMF treatment had a relatively small but statistically significant effect on the reduction of the active acidity value in the case of using the most energetically powerful variants of CMF treatments--mainly in relation to albumen (from approximately 9.2 to approximately 9.0-9.1) and liquid whole eggs (from about 8.1 to about 7.9). Active acidity (pH) may be one of the factors in \"hurdle technology\" to better inactivate undesirable microbes in liquid foods. For example, studies by [PERSON] et al. [27] showed that inactivation of _Escherichia coli_ in orange juice with different pH, subjected to Pulsed Electric Field (PEF) treatment, was statistically greater at higher pH values. Relationships between the impact of new preservation technologies, including PEF, on the pH value of a liquid food product in the context of effective microbiological inactivation have been analyzed by various research teams [28]. This has practical implications for the risk assessment of using new technologies, especially for more acidic products. There is no certainty in which pH ranges of egg raw materials the impact of new technologies could have a stronger inactivation effect of individual microorganisms. Earlier own research showed a significant positive, very high correlation (0.704) between the pH value and the degree of inactivation of _Escherichia coli_ after the PEF treatment, and no such correlation was found after CMF treatment [16]. The pH value, as well as the addition of lysozyme, may potentially be one of the additional factors in \"hurdle technologies\", also in the context of pH\(-\)lysozyme interactions, as analyzed in the [PERSON] study [29]. In our study, a statistically significant slight decrease in the pH value after the CMF treatment was found for most variants of the albumen, yolk and liquid whole eggs, which can be considered a favorable phenomenon, especially since there is more ovomucin in fresh egg raw material. Alkalization of albumen is a natural phenomenon associated with the release of carbon dioxide from egg content [30]. According to the data presented by [PERSON] et al. [31], there is a negative correlation between the content of ovomucin and pH. Considering the above, it may be concluded that changes in the albumen alkalinity will significantly reduce the value of other egg quality assessment parameters [32]. Own research showed that CMF treatment did not alkaline the egg raw material, on the contrary, it influenced its slight acidification, which may positively influence the extension of the shelf life of the final product. It is a particularly valuable property of CMF treatment, especially since other methods usually alkaline the egg raw material, e.g., after ultrasound treatment the pH value increases by approximately 0.7, and after heat treatment (64 \({}^{\circ}\)C/3 min) by approximately 0.4 [33]. Color and aroma are probably the most relevant quality attributes for fresh eggs and liquid egg products because they are simple indicators of microbiological spoilage [34]. The color of the liquid whole eggs depends primarily on the chemical composition of the yolk, which is closely related to the feeding of laying hens and the natural pigments contained in the feed, mainly xanthophylls and carotenoids present in dried and green fodder, e.g., from alfalfa or maize [35]. Technological processes may also affect the color of the LWE, which is usually associated with denaturation processes (even partial ones) due to temperature or other treatment factors. Thermal treatment on the LWE may lead to a darkening of the samples, e.g., by 6 L* units, with no significant effect on the a* and b* parameters [33]. From the consumer point of view, it cannot be clearly stated whether the darker egg product is a favorable phenomenon, as it depends on local preferences.