New cardboard active tray based on nanoencapsulated essential oils in β-cyclodextrins. Optimization of the industrial manufacturing process

[SPA] Es preciso avanzar en tecnología de envasado activo antimicrobiano, para diferenciar todavía más la calidad y vida útil de los productos hortofrutícolas frescos frente a la competencia, haciendo especial hincapié en la mejora de su calidad microbiológica y de su seguridad alimentaria. Por tanto, el objetivo principal de este trabajo será obtener a escala industrial un nuevo envase de cartón antimicrobiano, que aumentará significativamente la vida útil del producto, además de garantizar la seguridad alimentaria del mismo. Para ello, se incorporarán al envase aceites esenciales nanoencapsulados en β-ciclodextrinas. Además, se optimizarán las propiedades físicas de este nuevo envase, para que pueda fabricarse de forma óptima a escala industrial, respondiendo a las especificaciones mecánicas necesarias. Se estudiará cómo varían, en función de la composición, las propiedades físicas de la solución de recubrimiento del envase, y las propiedades físicas del cartón. El último paso será optimizar las condiciones y parámetros para su fabricación a escala industrial, minimizando el coste de todo el proceso. [ENG] It is necessary to advance in antimicrobial active packaging technology for fresh fruits and vegetables. In this way, it will be possible to reach a more differentiated quality and shelf-life against competitors, with particular emphasis on improving their microbiological quality and food safety. Therefore, the main objective of this project is to obtain -at industrial scale- a new cardboard tray with antimicrobial properties, which significantly increases the shelf life of the product, as well as guarantee food safety. For this, essential oils nanoencapsulated in β-cyclodextrins are incorporated as coating on the package surface. In addition, the physical properties of this new packaging will be optimized, so that it can be manufactured optimally at industrial scale, responding to the necessary mechanical specifications. The physical properties of the coating solution and the cardboard will be studied as a function on the coating composition. The last step will be to optimize the conditions of manufacturing at industrial scale, minimizing the cost of the whole process.Esta Tesis doctoral se desarrollará dentro del Proyecto titulado “Nueva caja de cartón activa antimicrobiana para alargar la vida útil de tomates y pimientos frescos envasados a granel — CARTONFRESH”, financiado por el Programa RIS3-Mur 2016 (Convocatoria RIS3Mur- Orden 12 agosto 2016 de la Consejería de Desarrollo Económico, Turismo y Empleo, Región de Murcia). Exp. nº: 2 / 16SAE00006, que lo llevará a cabo la empresa SAECO S.A. (Cartón Ondulado, Molina de Segura, Murcia) en colaboración con la Universidad Politécnica de Cartagena (Grupo de Investigación Ingeniería del Frío y la Seguridad Alimentaria, IFSA)

Effect of different technologies (conventional thermal treatment, microwave…) and stress conditions (acid shock) on Listeria monocytogenes in food

[SPA] Los microorganismos poseen capacidad de desarrollar respuestas de carácter adaptativo cuando han sido sometidos a condiciones subletales, activando mecanismos generales de defensa capaces de provocar un aumento en su resistencia a éste y otros estreses, entre los que se encuentran los diferentes métodos de conservación de alimentos. Entre los métodos de inactivación bacteriana a nivel industrial, el tratamiento térmico convencional presenta numerosas ventajas y es uno de los más extensamente utilizados. Sin embargo, el procesado con microondas tiene también ventajas y no es tan empleado. Por lo tanto, el presente proyecto tiene como objetivos la determinación del efecto de diferentes condiciones de estrés, como un choque ácido, así como el efecto del pH del medio de calentamiento sobre la inactivación y daño subletal de Listeria monocytogenes sometida a tecnologías como un tratamiento térmico convencional y tratamiento por microondas, entre otros, en alimento. [ENG] Microorganisms have the ability to develop adaptive responses when they are subjected to sublethal conditions, triggering general defense mechanisms which are capable to increase resistance to this and other stresses, among those it’s can be found the different methods of food preservation. Among the methods of bacterial inactivation at the industrial level, conventional thermal treatments present many advantages and is one of the most widely used. However, microwave processing, although has also several advantages is not so high employed. Therefore, the present project aims at determining the effect of different stressing conditions like acid shock as well as the effect of the heating medium pH on the inactivation and sublethal damage of Listeria monocytogenes treated with technologies such as conventional thermal and microwaves treatments, among others, in food.Esta investigación está siendo posible gracias al apoyo financiero proporcionado por el Ministerio de Economía y Competitividad, a través del proyecto AGL-2013- 48993-C2-1-R

Effect of microwave thermal treatment and stress conditions (acid shoc) on Listeria monocytogenes in food

[SPA] Los microorganismos poseen capacidad de desarrollar respuestas de carácter adaptativo cuando han sido sometidos a condiciones subletales, activando mecanismos generales de defensa capaces de provocar un aumento en su resistencia a éste y otros estreses, entre los que se encuentran los diferentes métodos de conservación de alimentos. Entre los métodos de inactivación bacteriana a nivel industrial, el tratamiento térmico convencional presenta numerosas ventajas y es uno de los más extensamente utilizados. Sin embargo, el procesado con microondas tiene también ventajas y no es tan empleado. Por lo tanto, el presente proyecto tiene como objetivos la determinación del efecto de diferentes condiciones de estrés, como un choque ácido, así como el efecto del pH del medio de calentamiento sobre la inactivación de Listeria monocytogenes sometida a tecnologías como un tratamiento térmico convencional y tratamiento por microondas, entre otros, en alimento. Los resultados mostraron que un choque ácido afecta a la termorresistencia del microorganismo, disminuyendo su resistencia a un calentamiento por microondas. [ENG] Microorganisms have the ability to develop adaptive responses when they are subjected to sublethal conditions, triggering general defense mechanisms which are capable to increase resistance to this and other stresses, among those it’s can be found the different methods of food preservation. Among the methods of bacterial inactivation at the industrial level, conventional thermal treatments present many advantages and is one of the most widely used. However, microwave processing, although has also several advantages is not so high employed. Therefore, the present project aims at determining the effect of different stressing conditions like acid shock as well as the effect of the heating medium pH on the inactivation of Listeria monocytogenes treated with technologies such as conventional thermal and microwaves treatments, among others, in food. The results obtained have shown that the acid shock affects the microorganism thermoresistance by decreasing its resistance by microwave heating.Ministerio de Economía y Competitividad, proyecto AGL-2013- 48993-C2-1-R

The potential of essential oils from active packaging to reduce ethylene biosynthesis in plant products. Part 2: fruits (Blueberries and blackberries)

Plant essential oils (EOs) have an important ability to inhibit ethylene biosynthesis. Nevertheless, the effects of EOs on the key components of ethylene biosynthesis (l-aminocyclopropane1-carboxylic (ACC) oxidase activity, ACC synthase activity, and ACC content) have not yet been thoroughly studied. Accordingly, this study focused on the effects of emitted EOs from active packaging (EO doses from 100 to 1000 mg m−2 ) on the key components of ethylene biosynthesis of blueberries and blackberries under several storage temperatures. Anise EO and lemon EO active packaging induced the greatest inhibitory effects (60–76%) on the ethylene production of blueberries and blackberries, respectively, even at high storage temperatures (22 ◦C). In terms of EO doses, active packaging with 1000 mg m−2 of anise EO or lemon EO led to the highest reduction of ethylene production, respectively. At 22 ◦C, the investigated EO active packing reduced the activities of ACC synthase and ACC oxidase up to 50%. In order to minimise ethylene biosynthesis in blueberries and blackberries when they are stored even under improper temperature scenarios at high temperatures, this EO active packaging is a natural and efficient technological solution.The authors are grateful to the SPANISH MINISTRY OF SCIENCE AND INNOVATION for the grant PID2020-119882RB-I00 funded by MCIN/AEI/10.13039/501100011033. Ginés Benito Martínez- Hernández was supported by a Beatriz Galindo scholarship (BG20-00069) from the SPANISH MINISTRY OF SCIENCE AND INNOVATION. Alberto Garre was supported by a Ramón y Cajal scholarship (RYC2021-034612-I) from the SPANISH MINISTRY OF SCIENCE AND INNOVATION. The authors are grateful to the company, Plus Berries, for facilitating the transport of blackberries to the facilities of the Universidad Politécnica de Cartagena

Kinetics of carvacrol release from active paper packaging for fresh fruits and vegetables under conditions of open and closed package

The carvacrol release kinetics from active packaging (including carvacrol-βcyclodextrin inclusion complex) was studied under the following possible scenarios found in fresh produce packaging and marketing facilities: different storage temperatures (2, 8, 15 and 22 ºC), relative humidity (60% and 95% RH), as well as different packaging conditions (open or closed). Release kinetics for the closed and open packaging systems were described using first-order and n-order power law kinetics, respectively. Increasing temperature and RH enhanced the carvacrol release rate. The release rate (k) increased by 1.3–1.7-fold when the RH was augmented from 60% to 95%. An initial release burst effect was observed with the highest k rate (0.14/2.0 × 10− 2 1/dayn ) under open active packaging at 8/15 ºC (95% RH). In conclusion, the use of active packaging will ensure a proper essential oil release, with even a higher initial release (burst effect) in open packages, leading to a potential extension of the product shelf life.The authors are grateful for the grant PID2020-119882RB-I00 funded by MCIN/AEI/ 10.13039/501100011033. Alberto Garre was supported by a Ramon y Cajal scholarship from the Spanish Ministry of Science and Innovation/State Investigation Agency from Spain (RYC2021-034612-I)

High heating rates affect greatly the inactivation rate of Escherichia coli

Heat resistance of microorganisms can be affected by different influencing factors. Although, the effect of heating rates has been scarcely explored by the scientific community, recent researches have unraveled its important effect on the thermal resistance of different species of vegetative bacteria. Typically heating rates described in the literature ranged from 1 to 20°C/min but the impact of much higher heating rates is unclear. The aim of this research was to explore the effect of different heating rates, such as those currently achieved in the heat exchangers used in the food industry, on the heat resistance of Escherichia coli. A pilot plant tubular heat exchanger and a thermoresistometer Mastia were used for this purpose. Results showed that fast heating rates had a deep impact on the thermal resistance of E. coli. Heating rates between 20 and 50°C/min were achieved in the heat exchanger, which were much slower than those around 20°C/s achieved in the thermoresistometer. In all cases, these high heating rates led to higher inactivation than expected: in the heat exchanger, for all the experiments performed, when the observed inactivation had reached about seven log cycles, the predictions estimated about 1 log cycle of inactivation; in the thermoresistometer these differences between observed and predicted values were even more than 10 times higher, from 4.07 log cycles observed to 0.34 predicted at a flow rate of 70 mL/min and a maximum heating rate of 14.7°C/s. A quantification of the impact of the heating rates on the level of inactivation achieved was established. These results point out the important effect that the heating rate has on the thermal resistance of E. coli, with high heating rates resulting in an additional sensitization to heat and therefore an effective food safety strategy in terms of food processing.This research was financially supported by the Ministry of Economy and Competitiveness of the Spanish Government and European Regional Development Fund (ERDF) through project AGL2013-48993-C2-1-

Impact of heating rates on alicyclobacillus acidoterrestris heat resistance under non-isothermal treatments and use of mathematical modelling to optimize orange juice processing

Alicyclobacillus acidoterrestris is a spoilage microorganism responsible for relevant product and economic losses in the beverage and juice industry. Spores of this microorganism can survive industrial heat treatments and cause spoilage during posterior storage. Therefore, an effective design of processing treatments requires an accurate understanding of the heat resistance of this microorganism. Considering that industrial treatments are dynamic; this understanding must include how the heat resistance of the microorganism is affected by the heating rate during the heating and cooling phases. The main objective of this study was to establish the effect of heating rates and complex thermal treatments on the inactivation kinetics of A. acidoterrestris. Isothermal experiments between 90 and 105 C were carried out in a Mastia thermoresistometer, as well as four different dynamic treatments. Although most of the inactivation takes place during the holding phase, our results indicate the relevance of the heating phase for the effectiveness of the treatment. The thermal resistance of A. acidoterrestris is affected by the heating rate during the heating phase. Specifically, higher heating rates resulted in an increased microbial inactivation with respect to the one predicted based on isothermal experiments. These results provide novel information regarding the heat response of this microorganism, which can be valuable for the design of effective heat treatments to improve product safety and stability. Moreover, it highlights the need to incorporate experimental data based on dynamic treatments in process design, as heating rates can have a very significant effect on the thermal resistance of microorganisms.This research was funded by Ministerio de Economía, Industria y Competitividad of the Spanish Government, grant number AGL2017-86840-C2-1-R. Alberto Garre acknowledges the support from a postdoctoral grant by the Fundación Séneca, Murcia Region (20900/PD/18) in WU

Avances en Ciencias y Técnicas del Frío - 11

Este año 2022 se han cumplido 20 años desde la fundación de la Sociedad Española de Ciencias y Técnicas del Frío (SECYTEF; http://secytef.upct.es/), que tuvo lugar precisamente en la Universidad Politécnica de Cartagena, durante la celebración en esta Universidad del primer congreso CYTEF en 2002. Fue el Primer Congreso Español de Ciencias y Técnicas del Frío de esta serie de congresos CYTEF. Posteriormente, los congresos CYTEF han tenido lugar cada 2 años, y de su organización se ha encargado especialmente la SECYTEF, ya que es su principal cometido Los trabajos de investigación presentados en los Congresos CYTEF han sido publicados en los libros de actas correspondientes que constituyen una serie denominada Avances en Ciencias y Técnicas del Frío. Contando con este libro de Actas del CYTEF 2022, ya son 11 números de esta serie de libros los publicados. Representan una valiosa fuente de información científico-técnica para los investigadores, técnicos y profesionales interesados en las Ciencias y Técnicas del Frío, tanto en lo que se refiere a tecnologías de producción de frío, como a las tecnologías de su aplicación en los distintos sectores