Principios, aplicaciones y efectos de la aplicación de plasma frío en alimentos: una revisión actualizada

En el ámbito de las tecnologías no térmicas para el procesamiento de alimentos, la aplicación de plasma frío destaca por su rápido crecimiento y amplias proyecciones. El plasma frío se genera aplicando energía que ioniza un gas específico, lo que produce especies altamente reactivas como las reactivas de oxígeno y nitrógeno, además de ozono, iones, radicales libres y radiación ultravioleta. Las configuraciones más comunes para su generación incluyen la descarga de barrera dieléctrica y la descarga corona. Sus aplicaciones y efectos clave abarcan la destrucción de biofilms, inactivación de microorganismos, descontaminación de micotoxinas, degradación de pesticidas y modificación de almidones, entre otros. Los mecanismos de acción propuestos varían desde modificaciones químicas y moleculares hasta lisis celular y daño genético. Este artículo proporciona una visión general actualizada sobre los principios, generación y aplicaciones del plasma frío en la industria alimentaria.

In the field of non-thermal food processing technologies, the application of cold plasma stands out for its rapid growth and broad prospects. Cold plasma is generated by applying energy to ionize a specific gas, producing highly reactive species such as reactive oxygen and nitrogen species, as well as ozone, ions, free radicals, and ultraviolet radiation. The most common configurations for generating cold plasma include dielectric barrier discharge and corona discharge. Key applications and effects include the destruction of biofilms, inactivation of microorganisms, decontamination of mycotoxins, degradation of pesticides, and modification of starches, among others. Proposed mechanisms of action range from chemical and molecular modifications to cellular lysis and genetic damage. This article provides an updated overview of the principles, generation, and applications of cold plasma technology in the food industry.

High-intensity ultrasound influences the probiotic fermentation of Baru almond beverages and impacts the bioaccessibility of phenolics and fatty acids, sensory properties, and in vitro biological activity.

High-intensity ultrasound (HIUS, 20 kHz, 450 W, 6 min) was used as an alternative to the pasteurization of a water-soluble Baru almond extract (WSBAE). Then, probiotic fermented beverages (Lacticaseibacillus casei) were processed and evaluated during storage (7 °C, 28 days). Four formulations were prepared: RAW (untreated [no pasteurization or ultrasound] and unfermented WSBAE), PAST (pasteurized WSBAE fermented with probiotic), U-BEF (WSBAE added with probiotic, submitted to ultrasound, and fermented), and U-AFTER (WSBAE submitted to ultrasound, added with probiotic, and fermented). PAST and HIUS-treated beverages had similar microbiological quality. The PAST formulation showed decreased monounsaturated fatty acids, compromised health indices, and had the lowest consistency. U-AFTER showed higher concentrations of lactic and acetic acids, lower bioaccessibility for most phenolics and fatty acids, and reduced consumer acceptance. U-BEF had the fermentation time reduced by 13.64%, higher probiotic survival during storage and simulated gastrointestinal conditions, and higher bioaccessibility of phenolics and fatty acids during storage. Furthermore, it presented higher in vitro antidiabetic properties and improved consistency and stability. Finally, U-BEF had improved volatile compound composition, resulting in increased sensory acceptance and improved sensory properties. Our results indicate that the HIUS applied after probiotic addition may be a suitable alternative to pasteurization in the processing of fermented beverages, resulting in reduced fermentation times and improved technological, sensory, and biological properties.

Pulsed electric field assisted extraction of natural food pigments and colorings from plant matrices.

Coloring compounds are widely applied to manufacturing foods and beverages. The worldwide food market is replacing artificial colorants with natural alternatives, given the increased consumer demand for natural products. However, these substitutes are still an issue due to their high production cost and low chemical and physical stability. Furthermore, natural pigments are highly sensitive to processes applied in conventional extraction techniques, such as thermal, mechanical, and chemical stresses. In this regard, pulsed electric field (PEF) technology has emerged as a promising non-thermal alternative for recovering and producing natural colorings from food matrices. Its action mechanism on cell structures through the electroporation effect is a smart alternative to overcoming the challenging issues associated with producing natural colorants. In this scenario, this review provides an overview of the PEF assisted extraction of natural pigments and colorants, such as anthocyanins (red-blue-purple), betalains (red), carotenoids (yellow-orange-red), and chlorophylls (green) from plant sources. Moreover, the potential and limitations of this emerging technology to integrate the extraction process of natural colorants were discussed.

Tecnología emergente: Campo de pulsos eléctricos (PEF) para el tratamiento de alimentos y su efecto en el contenido de antioxidantes

RESUMEN Los métodos de conservación de alimentos no-térmicos han generado un considerable interés en la industria alimentaria como potencial alternativo a los métodos tradicionales de procesamiento. Uno de los métodos no-térmicos más estudiados es el de campos eléctricos pulsados o PEF (Pulsed Electric Fields). La aplicación de PEF en el procesamiento de alimentos permite limitar la exposición a altas temperaturas y reducir la necesidad de aditivos alimentarios. En PEF, se expone al alimento a pulsos eléctricos generando poros en la membrana celular, este fenómeno se le conoce como electroporación. La electroporación promueve la inactivación de organismos patógenos, reduce la actividad enzimática, favorece la transferencia de masa, mantención de color, sabor y contenido de compuestos antioxidantes, mejora la eficiencia en el procesamiento de alimentos y mantiene de cualidades organolépticas que son atractivas tanto para el consumidor como también para la industria. Los antioxidantes son sustancias capaces de proteger a las células de los radicales libres. La acción de los antioxidantes es de interés tanto del punto de vista sanitario, como industrial. Existe abundante evidencia que asocia el consumo de antioxidantes como factor protector ante enfermedades. Por otro lado, los antioxidantes cumplen un rol importante en la duración de los alimentos ya que actúan como conservantes, prolongando su vida útil. La utilización de PEF, respecto a otras tecnologías para el procesamiento de alimentos, ha demostrado un aumento en la extracción, menor pérdida por temperatura y una mayor disponibilidad de compuestos de interés, incluidos antioxidantes.

ABSTRACT Non-thermal food preservation methods have gained considerable interest in the food industry as a potential alternative to traditional processing methods. One of the most studied non-thermal methods is Pulsed Electric Fields (PEF). The application of PEF in food processing allows limiting exposure to high temperatures and reducing the need for food additives. In PEF, food is exposed to electrical pulses generating pores in the cell membrane, this phenomenon is known as electroporation. Electroporation promotes the inactivation of pathogenic organisms, reduces enzyme activity, favors mass transfer, maintains color, flavor and antioxidant compound content, improves food processing efficiency and maintains organoleptic qualities that are attractive to both the consumer and the industry. Antioxidants are substances capable of protecting cells from free radicals. The action of antioxidants is of interest both from a health and industrial point of view. There is abundant evidence that associates the consumption of antioxidants as a protective factor against diseases. On the other hand, antioxidants play an important role in the shelf life of foods as they act as preservatives, prolonging their shelf life. The use of PEF, compared to other food processing technologies, has shown an increase in extraction, lower temperature loss and greater availability of compounds of interest, including antioxidants.

Thermal and non-thermal processing effect on açai juice composition.

This study evaluated the effects of High-Temperature Short Time (HTST), Ultra High Temperature (UHT), and the non-thermal processes High Power Ultrasound (US), UV-pulsed-light and Low Pressure Plasma (LPP) on the composition, stability, and bioactive compounds bioaccessibility of açai juice. 1H NMR based approach, coupled to chemometrics, was applied to evaluate the changes in the juice composition. All the non-thermal processes increased the sugars content (glucose and fructose), and the amino acid betaine, except the combined processing of ultrasound followed by low-pressure plasma (US.LPP). HTST and UHT increased the fatty acids and phenolic compounds content in the açai juice. The bioaccessibility of phenolic compounds decreased due to the processing. After thermal sterilization (UHT), the anthocyanin bioaccessibility was 2-fold higher. The combined non-thermal treatment reduced the biocompounds bioaccessibility to 40% of the non-processed juice. However, the combined US.LPP improved the bioaccessibility of vitamin C by 8%. UHT increased the anthocyanin's bioaccessibility but sharply decreased vitamin C bioaccessibility. Higher impact of thermal processing on vitamin C, anthocyanins, total phenolics, PPO, POD, DPPH, ABTS, and FRAP was verified after 45 and 60 days of storage compared to the non-thermally processed samples.

Ozone and plasma processing effect on green coconut water.

In this study, the effect of plasma and ozone processing on the quality of coconut water was evaluated. For ozone processing, the samples were submitted to different ozone loads and temperatures. For atmospheric cold plasma processing (ACP), samples were exposed to plasma under different frequencies and voltages. The coconut water pH, soluble solids, titratable acidity, color, total phenolic content, and enzymatic activity were determined before and after treatments. The main compounds were also determined by NMR spectroscopy and chemometric analysis. Both processes did not change the pH values, total soluble solids, titratable acidity, and color. Chemometrics analysis of 1H NMR dataset showed no relevant changes after the processing. All ozone treatments promoted complete inactivation of POD activity and did not affect the content of phenolic compounds. After ACP, the smallest POD residual activity was observed when higher frequencies were applied, and slight changes in phenolic compounds content were observed.

High-intensity ultrasound energy density: How different modes of application influence the quality parameters of a dairy beverage.

This study evaluated the influence of the high-intensity ultrasound (HIUS) technology on the quality parameters of a model dairy beverage (chocolate whey beverage), operating under the same energy density (5000 J/mL), but applied at different ways. Two processes were performed varying nominal power and processing time: HIUS-A (160 W and 937 s), and HIUS-B (720 W and 208 s). Our objective was to understand how different modes of application of the same HIUS energy density could influence the microstructure, droplet size distribution, zeta potential, phase separation kinetic, color parameters and mineral profile of the chocolate whey beverage. The results demonstrated that the different modes of application of the same HIUS energy density directly influenced the final quality of the product, resulting in whey beverages with distinct physical and microstructural characteristics. The HIUS-B processing was characterized as a thermal processing, since the final processing temperature reached 71 °C, while the HIUS-A processing was a non-thermal process, reaching a final temperature of 34 °C. Moreover, HIUS-B process greatly reduced the droplet size and increased the lightness value in relation to the HIUS-A processing. Both treatments resulted in whey beverages with similar phase separation kinetics and were more stable than the untreated sample. The HIUS processes did not modify the mineral content profile. Overall, the study emphasizes the versatility of the HIUS technology, highlighting that the processing must not be based only on the applied energy density, since different powers and processing times produce dairy beverages with distinct characteristics.