Non-thermal Technologies

Non-thermal technologies have been studied for many years, with new developments being discovered and continuously improved. Some technologies, such as high-pressure processing and pulsed electric field have been used in industrial processes for at least three decades. Non-thermal technologies, such as ultrasound, cold plasma, ozone, pulsed electric field and pulse ultraviolet (UV) light can be used in sanitization of food products, but also to improve the sensorial and nutritional quality of foods. Up to now, it has been shown that non-thermal technologies can inactivate, at different degrees, most food pathogenic microorganisms; and as it becomes more accessible, its use by the industry is becoming a reality. But, since these technologies affect the organic matter of microorganisms, how do they affect our food? Recent studies are reporting that these non-thermal technologies may also change the food tissue structure, enzymes, metabolic rates, phenolics, antioxidants, vitamins, color and other sensory and nutritional aspects of our food. Under some circumstances the changes are positive, improving the phenolic and free vitamin content, inactivating color degrading enzymes and improving cloud stability in juices. However, there are also reports on negative effects such as color fading, texture loss and production of off-flavor.

The application of these non-thermal processes in sanitization has been highly explored over the last 10 years, and the knowledge of the strains of microorganisms that can be inactivated and how this inactivation is achieved has been the focus of much of this research. On the other hand, reports on other effects of non-thermal technologies on food is still missing. As food quality and nutrition becomes a major concern in the modern world, it is not possible anymore to rely on technologies that sanitize our food but at the same time, also reduce their sensory and nutritional quality. As such, the effects of non-thermal processing on food quality still needs further investigation. More information is also needed to understand how these techniques can be applied to improve the quality or, to reduce possible side effects of their application. This Research Topic welcomes studies that report on the effects and mechanisms by which non-thermal processes induce changes on food tissue structure, enzymes, metabolic rates, phenolics, antioxidant capacity, vitamins, color, lipid stability, sensory changes, production of off-flavors and other nutritional and sensory aspects of food, whether positive or negative. Studies on the combination and synergy of two or more processes are also welcome. This Research Topic especially welcomes studies that cover the interaction between these emerging technologies and nutrition, including chemometric, nuclear magnetic resonance, gas chromatography, liquid chromatography and other traceability techniques.

This Research Topic therefore welcomes manuscripts on the physical, chemical and sensorial changes induced by non-thermal technologies with a focus on, but not limited to:
• Ozone, ultrasound, pulsed UV light, cold plasma and high pressure processing
• Effects of non-thermal technologies on phenolics, flavonoids and anthocyanins
• Effects of non-thermal technologies on food enzymes
• Effects of non-thermal technologies on vitamins
• Effects of non-thermal technologies on antioxidant capacity
• Nuclear magnetic resonance and chemometric studies on foods subjected to non-thermal treatments
• Gas chromatography and liquid chromatography studies on foods subjected to non-thermal treatments

Antonio Morata holds patents in wine technology specifically related to aging on lees, grape skin separation and brettanomyces analysis. All other Topic Editors declare no competing interests with regard to the Research Topic subject.