Nuevo envase activo y antimicrobiano para la conservación de productos vegetales

[ENG] The food packaging industry is demanding new packages able to improve the quality of the packed products. In this regard some of the problems to be solved are the recyclable and compostable character of the materials, the antimicrobial properties of some substances to be involved in the packaging system and the optimum control of the internal atmosphere in the package. As a solution for these problems a new flow-pack active packaging design was proposed to be developed in this investigation, based on Polylactic acid (PLA)-coated cardboard trays, with some active substances embedded into this coating (plant essential oils and gases scavengers) and the suitable wrapping film. The antimicrobial effect of this new package was studied using plant essential oils embedded in the inner coating of the cardboard tray. Essential oils are aromatic and volatile liquids extracted from plants. The chemicals in essential oils are secondary metabolites, which play an important role in plant defense, as they often possess antimicrobial properties. The interest in essential oils and their application in food preservation have been amplified in recent years by an increasingly negative consumer perception of synthetic preservatives. Furthermore, food-borne diseases are a growing public health problem worldwide, calling for more effective preservation strategies. The antibacterial properties of essential oils and their constituents have been documented extensively. The main obstacle for using essential oil constituents as food preservatives is that they are most often not powerful enough as single components, and they cause negative sensorial effects when added in sufficient amounts to provide an antimicrobial effect. Exploiting synergies between different essential oils has been suggested as a solution to this problem. The effect of them in antimicrobial packaging systems has been little studied. Because of the latter the proposal for this research was the use of a combination of vanillin, and essential oils of clove, cinnamon and thyme as antimicrobials in the new model of package. Cardboard trays coated with a film of PLA were studied in order to obtain a new active packaging friendly with the environment. During this investigation the PLA showed active properties in relation with the control of the internal atmosphere of the package used to storage “Cherry” tomatoes. This polymer belongs to the family of aliphatic polyesters commonly made from α-hydroxy acids, which include polyglycolic acid or polymandelic acid, and are considered biodegradable and compostable. PLA is a thermoplastic, high-strength, high-modulus polymer that can be made from annually renewable resources to yield articles for use in either the industrial packaging field or the biocompatible/bioabsorbable medical device market. It is easily processed on standard plastics equipment to yield molded parts, film, or fibers. In addition, it can be used for food contact and are generally recognized as safe (GRAS). PLA is degraded by simple hydrolysis of the ester bond and does not require the presence of enzymes to catalyze this hydrolysis. The rate of degradation is dependent on the size and shape of the article, the isomer ratio, and the temperature of hydrolysis. Ethylene has diverse and significant effects on plant physiology. These are usually negative for the quality and shelf life of most horticultural products since this gas accelerates maturation and senescence. Modifications of the atmosphere inside the package can decrease O2 and increase CO2 in its interior, which allows the respiration and the production of ethylene by the fruit in the packaging to be reduced. O2 and CO2 modified atmosphere packages have been positively used to preserve fresh-cut tomatoes from damages. Also absorbent substances held on various inert support materials are commonly used to remove ethylene in various postharvest situations. Potassium permanganate (KMnO4) is usually used for this purpose, being added to different absorbent materials such as activated carbon, silica gel, aluminum oxide, and clay minerals like sepiolite, to complement the properties of the active packaging. For all the above the experimental design of this investigation consisted in the following research lines: - The study of antimicrobial activity of the plant essential oils, individually and combinations of them, “in vitro” and in a food model system. - Characterization of physical and water barrier properties, for the PLA-coated cardboard, with or without some gasses scavengers. - Assesment of the practical application of the latter results in a new active packaging design with ethylene adsorption and antimicrobial characteristics. This evaluation was performed using as model food “Cherry” tomatoes. The present work has yielded some interesting results for the packaging industry. The use of vanillin and the essential oils of clove, thyme and cinnamon showed effective antimicrobial activity against L. monocytogenes and E. coli O157:H7 “in vitro” and in the tested food model system at the concentrations used as food flavouring agent. The application of these substances in the PLA coating films has shown antimicrobial activity against the target strains studied in this work. Mixtures of plant essential oils of clove, thyme and cinnamon leaves with vanillin also inhibited the growth of L. monocytogenes showing a marked synergistic effect. It could be reasonable to use these mixtures to lower the individual sensorial impact on the packed food and to enlarge the spectrum of sensitive microorganisms to this antimicrobial activity. The physical properties (thickness, weight, smoothness) and water barrier properties of PLA-coated cardboard (Water vapor permeability (WVP), Water absorptivity (WA), wetting energy (WE), and contact angle (CA)) showed an improvement of impermeability. The use of clays additives (Clinoptinolite, Sepiolite, or Sepiolite- Permanganate) reported as gasses scavengers increased the water affinity of PLAcoated paperboard but not as much as the uncoated samples. The embedding of those clays additives in the PLA coating film helps to control the humidity in the internal atmosphere of the package. These results represent an advantage for the manufacture of cardboard trays with improved humidity behavior. The compostable and environmentally friendly nature of PLA amplifies these advantages. The best results were obtained for PLA 2% alone or with Clinoptinolite 1.5% or with 1% of Sepiolite Permanganate, these conditions were the most effective in increasing the water barrier properties of cardboard. These coatings are suitable for use in cardboard trays for the packaging, storage, and transport of foods such as fresh fruit and vegetables. The PLA coating on the inside of the cardboard trays has demonstrated a very significant effect on the adsorption of ethylene and water vapour, and can be used in active packaging systems intended to “Cherry” tomatoes to regulate both factors. When this new active packaging design is applied to the preservation of “Cherry” tomatoes it is shown that in early stages of storage, there is a little production of water vapour and a high production of ethylene, which is adsorbed in the PLA layer. In later stages, ethylene production in tomatoes falls and water vapour production increases, so that ethylene may be exchanged for water vapour in the PLA layer, allowing the progressive exit of small amounts of ethylene through the wall of the thin LDPE wrapping film. Passive modified atmosphere packaging in combination with active packaging using PLA-coated cardboard trays wrapped with thin LDPE film has significantly extended the shelf life of fresh tomatoes. This is a good solution for fresh tomato packaging compared with packaging systems using trays wrapped with macroperforated films because microbial safety is better, while ethylene concentration inside the package is controlled at the same time. In addition, with the studied active packaging system, there is a considerable saving of energy during the storage and distribution of fresh tomatoes, as the storage temperature is 20° C, much higher than the storage temperatures usually used with modified atmosphere packaging. As a result of this thesis work, a new active packaging system has been patented. This system is based on PLA-coated cardboard trays, wrapped and thermo-sealed with LDPE film (20 μm thickness), which allows to prolong the shelf life of fresh vegetables. Some claims of this patent consider the addition of clays additives and plant essential oils to the PLA coating film in order to enhance the preservation of the packed food, acting as gasses scavengers and antimicrobials respectively. [ESP]Se estudió el efecto antimicrobiano de este nuevo envase con aceites esenciales de plantas inmersos en el recubrimiento interior de PLA de la superficie de la bandeja de cartón. Los aceites esenciales son sustancias aromáticas y volátiles extraídas de las plantas, son metabolitos secundarios, que desempeñan un papel importante en la defensa de la planta, debido en gran parte a sus propiedades antimicrobianas. El interés por los aceites esenciales y su aplicación en la conservación de alimentos se ha incrementado en los últimos años debido a la percepción cada vez más negativa de los consumidores por los conservantes sintéticos. Por otra parte, las enfermedades transmitidas por alimentos son un problema creciente en la salud pública, lo que exige estrategias de conservación más eficaces. Las propiedades antibacterianas de los aceites esenciales y sus componentes se han documentado ampliamente. Los principales obstáculos para el uso aceites esenciales como conservantes de alimentos es que no son suficientemente potentes de manera individual y el efecto sensorial suele ser negativo cuando se añaden en cantidades suficientes para proporcionar un efecto antimicrobiano. La explotación de las sinergias entre los diferentes aceites esenciales ha sido sugerido como una solución a este problema. El efecto de ellos en los sistemas de envasado antimicrobianos ha sido poco estudiado, por lo que este trabajo de investigación se propuso el estudio de un envase activo utilizando como principios activos antimicrobianos una combinación de vainillina, y aceites esenciales de clavo, canela y tomillo. Las bandejas de cartón recubiertas con una película de PLA se estudiaron con el fin de obtener un nuevo envase activo reciclable y biodegradable. El PLA demostró propiedades activas en relación con el control de la atmósfera interna de un envase utilizado para almacenamiento de tomates "Cherry". Este polímero pertenece a la familia de los poliésteres alifáticos obtenidos a partir de ácidos α-hidroxiácidos, que incluyen ácido poliglicólico o ácido poli (mandélico), y son considerados biodegradables y compostables. El PLA tiene alta resistencia, es un termoplástico de alto módulo que se puede producir a partir de recursos renovables para producir artículos destinados al envasado industrial, dispositivos médicos, entre otros. Se procesa fácilmente en equipos de plástico estándar para producir piezas moldeadas, películas, o fibras. Además, puede ser utilizado para el contacto con alimentos y generalmente se reconoce como seguro (GRAS). Este plástico se degrada por simple hidrólisis del enlace éster y no requiere la presencia de enzimas para catalizar esta hidrólisis. La velocidad de degradación depende del tamaño y la forma, la relación de isómeros y la temperatura de la hidrólisis. En un envase destinado a productos frescos, sobre todo si son productos que liberan etileno podemos encontrar efectos diversos y significativos sobre el producto almacenado en dicho envase a lo largo de su vida útil. Estos efectos suelen ser negativos para la calidad de muchos productos frescos ya que este gas acelera la maduración y senescencia. Algunas modificaciones de la atmósfera interna del envase pueden disminuir los niveles O2 y CO2, lo que permite que la respiración y la producción de etileno por el producto envasado sean reducidas. El envasado en atmósfera modificadas de O2 y CO2 se ha utilizado de manera positiva para la conservación de vegetales frescos, ensaladas IV gama, frutas cortadas, etc. En este sentido también ha sido estudiado el uso de sustancias absorbentes de etileno, el permanganato potásico (KMnO4) es el más ampliamente conocido al igual que sus aplicaciones prácticas en la industria del envasado. Se utiliza generalmente en materiales de soporte, tales como carbón activado, gel de sílice, óxido de aluminio y minerales de arcilla (ej. sepiolita), para complementar las propiedades de un envasado activo. Por todo lo anterior, el diseño experimental de esta Tesis doctoral se basó en las siguientes líneas de investigación - El estudio de la actividad antimicrobiana de los aceites esenciales de las plantas, de forma individual y combinaciones de ellos, "in vitro" y en un sistema modelo de alimentos. - Caracterización de las propiedades físicas y barrera al agua para el cartón recubierto con PLA y con absorbentes de gases inmersos en el recubrimiento. - Evaluación de la aplicación práctica de los últimos resultados en un nuevo diseño de envases activos con adsorción de etileno y características antimicrobianas. Esta evaluación se realizó utilizando como modelo de productos frescos, tomates "Cherry". El presente trabajo ha dado algunos resultados interesantes para la industria del envasado. El uso de la vainillina y los aceites esenciales de clavo, tomillo y canela mostró actividad antimicrobiana efectiva contra L. monocytogenes y E. coli O157: H7 "in vitro" y en el sistema modelo de alimento probado con concentraciones habitualmente utilizadas como saborizante. La aplicación de estas sustancias en el recubrimiento de las películas de PLA ha demostrado actividad antimicrobiana frente a las cepas diana estudiadas en este trabajo. Las mezclas de aceites esenciales de plantas de clavo, tomillo y hojas de canela con vainillina también inhibieron sinérgicamente el crecimiento de L. monocytogenes. La utilización de estas mezclas puede ser razonable para reducir el impacto sensorial individual en el alimento envasado y para ampliar el espectro de microorganismos sensibles a esta actividad antimicrobiana. Las propiedades físicas (grosor, el peso, la suavidad) y las propiedades hidrofóbicas del cartón recubierto con PLA (permeabilidad al vapor de agua (PVA), capacidad de absorción de agua (WA), energía de humectación (NOS), y ángulo de contacto (CA)) mostraron una mejora en la impermeabilidad de la superficie interior del envase. El uso de arcillas (Clinoptinolita y sepiolita) y permanganato potásico como absorbentes de gases aumentó la afinidad por el agua de cartón recubierto de PLA, pero mucho menos que las muestras de cartón sin recubrir. La inmersión de estos absorbentes de gases en la película de revestimiento PLA ayudaron a controlar la humedad en la atmósfera interna del envase. Estos resultados representan una ventaja para la fabricación de bandejas de cartón con el comportamiento mejorado de la humedad interna. Las características como material biodegradable y reciclable del PLA incrementa sus ventajas como recubrimiento hidrofóbico. De acuerdo a nuestras observaciones, los mejores resultados fueron obtenidos con PLA 2%, PLA 2% con Clinoptinolita 1,5% y con PLA 2% con sepiolita-permanganato 1%, ya que estas condiciones fueron las más efectivas en el aumento de las propiedades barrera al agua del cartón. La caracterización hidrofóbica de los cartones con diferentes recubrimientos demostró que pueden ser utilizados para el envasado, almacenamiento y transporte de alimentos, como frutas y hortalizas frescas. Al mismo tiempo el recubrimiento de la superficie interior con PLA de las bandejas de cartón ha demostrado un efecto muy significativo en la adsorción de etileno y vapor de agua, y se puede utilizar en sistemas de envasado activo destinado a tomates "Cherry" para regular la atmósfera interior del envase. Cuando este nuevo envase activo se utiliza en la conservación de tomates "Cherry" se demuestra que en las primeras etapas de almacenamiento, hay una pequeña producción de vapor de agua y una alta producción de etileno, que es absorbido por la película de recubrimiento de PLA. En etapas posteriores, la producción de etileno en los tomates disminuye y aumenta la producción de vapor de agua, por lo que el etileno puede ser intercambiado por vapor de agua en la película de PLA, permitiendo la salida progresiva de pequeñas cantidades de etileno que difunde al exterior a través de la película de envoltura de polietileno de baja densidad (LDPE). Un envasado en atmósfera modificada pasiva en combinación con el envasado activo utilizando bandejas de cartón recubiertas con película de PLA y termosellados con película de LDPE ha prolongado de manera significativa la vida útil de los tomates envasados. Esta es una buena solución para el envasado de tomates frescos en comparación con los sistemas de envasado que utilizan bandejas envueltas con películas macro-perforadas porque mejora la seguridad microbiana y controla la concentración de etileno en el interior del envase al mismo tiempo. Además, con el sistema de envase activo desarrollado en este trabajo, se produce un ahorro considerable de energía durante el almacenamiento y la distribución de tomates frescos, porque permite que la temperatura de almacenamiento sea de 20° C, mucho más alta que las temperaturas de almacenamiento generalmente utilizadas en productos frescos envasados en atmósfera modificada. Como resultado de este trabajo de tesis, un nuevo sistema de envasado activo ha sido patentado. Este sistema se basa en bandejas de cartón recubiertos con PLA, envuelto y termo-sellado con película de LDPE (20 micras de espesor), lo que permite prolongar la vida útil de las hortalizas frescas almacenadas en el mismo. Algunas reivindicaciones de esta patente consideran la adición de arcillas y aceites esenciales de plantas a la película de revestimiento de PLA con el fin de mejorar la conservación de los alimentos envasados, en calidad de absorbentes de gases y antimicrobianos, respectivamente.Universidad Politécnica de Cartagen

Envase activo para conservación de productos vegetales frescos

Número de publicación: ES2393388 A1. También publicado como: ES2393388 B1. Número de solicitud: P201031030Envase activo para conservación de productos vegetales frescos. Se describe un recipiente de envasado, y un envase activo que lo comprende, con propiedades de adsorción del etileno, control del vapor de agua y capacidad antimicrobiana, de aplicación a productos vegetales frescos, en especial hortofrutícolas, con el que se modifica la atmósfera en el interior del envase, se controla la humedad y que actúa de barrera frente a los microorganismos, extendiendo la vida útil de los productos envasados, sin necesitar temperaturas bajas de conservación. Este envase activo consta de un recipiente de material biodegradable como el cartón, recubierto en su superficie interna de una lámina de un polímero con capacidad de absorción del etileno y vapor de agua, tal como PLA, en la que se incorporan aceites esenciales naturales con acción antimicrobiana, y de una película de envoltura que se aplica y termosella tras llenar el envase de producto.Universidad Politécnica de CartagenaUniversidad de Murci

Application of refrigeration for debittering table olives

During the process of making table olives, it is necessary to remove bitterness caused by phenolic compounds like oleuropein. This debittering effect is achieved by degrading these compounds into non-bitter ones that are beneficial for health due to their antioxidant properties. One of the most used methods is alkaline debittering using NaOH but the main drawback is the environmental impact generated by wastes and degradation of high-value nutraceutical compounds in olives. Different olive debittering pre-treatments followed by refrigeration storage at 5ºC during 90 days have been performed using Ocal variety olives (Olea europaea L.) by combining heat, β- glucosidase and Lactobacillus plantarum treatments. Oleuropein and hydroxytyrosol concentrations were determined in olive pulp and brine. The data has been complemented with sensory tests. The treatment with the best results was storage in refrigeration, which achieved significant debittering and greater degradation of oleuropein, due to the action of endogenous enzymes of the olives

Influencia de la limpieza del aire y de las superficies en instalaciones de envasado sobre la vida útil de productos agroalimentarios

[SPA] Algunos de los factores que más influyen sobre la calidad y la vida útil de los alimentos envasados no asépticamente son la carga microbiana inicial del producto antes de su procesado y la carga aportada durante el desarrollo de este procesado y del envasado, que tendrá como resultado la carga microbiana final del producto envasado. Esta carga microbiana dependerá en gran medida de la contaminación del aire de la sala de envasado y de las superficies de los equipos en contacto con el producto. Es por ello, que se ha llevado a cabo este estudio de caracterización y correlación de toda una serie de parámetros relativos al aire de la sala de envasado: temperatura, humedad relativa, velocidad del aire, concentración de partículas, recuento de unidades formadoras de colonias (UFC) en el aire, y la carga microbiana de las superficies de los equipos en contacto con el producto que se envasa. Esta carga microbiana del aire y de las superficies se ha relacionado con la evolución y vida útil de muestras de carne de cerdo y pavo cocido, que se han loncheado y envasado bajo dos condiciones de limpieza del aire y superficies: (i) en aire filtrado con flujo laminar (FL) (equivalente a sala blanca clase 100), y (ii) en condiciones de salas convencionales (SC) (en sala clase 100.000), y, posteriormente, se han almacenado a 4ºC. Las muestras se analizaron periódicamente hasta el final de su vida útil, determinando: la carga de enterobacterias, microflora total mesófila, microflora psicrotrofa, microflora láctica, Staphylococcus spp. Y Listeria monocytogenes; también, se determinaron los cambios organolépticos y de pH. Con la tecnología de loncheado y envasado en condiciones de flujo laminar se consiguió una mayor proporción de producto con recuentos inferiores a 10 UFC/g. En todos los casos, las muestras de carne de cerdo cocido presentaron valores inferiores a 104 UFC/g, y las de pavo cocido inferiores a 103 UFC/g. Esta significativa disminución de la carga microbiana inicial de los productos recién loncheados y envasados se tradujo en un claro aumento de su vida útil, en refrigeración a 4º C, que se amplió desde 18,6 días a 35,0 días, en el caso de la carne de cerdo cocida, y desde 32,3 a 49,2 días en el caso de la carne de pavo cocida. [ENG] The most important factors influencing the shelf life of cooked, sliced and packed meat products are the initial product quality and the factors of cutting and packaging process, mainly that’s concerning to the contamination control of air and equipment surfaces in contact with the product. This contamination will influences on the microbial load of the packaged product. Therefore the interest of the accomplishment of these operations protecting the The most important factors influencing the shelf life of cooked, sliced and packed meat products are the initial product quality and the factors of cutting and packaging process, mainly that’s concerning to the contamination control of air and equipment surfaces in contact with the product. This contamination will influences on the microbial load of the packaged product. Therefore the interest of the accomplishment of these operations protecting the product from the microbial contamination, using a cover of laminar flow with filtered air on the packaging line. In this study the shelf life of cooked ham and cooked turkey meat, sliced, packaged and stored in refrigeration (at 4º C) is analyzed, as function on the initial microbial load of the product, and the packaging technology: (i) under laminar flow (class 100 clean room) and (ii) in conventional clean room (class 100,000). The sliced and packaged product samples have been analyzed periodically until the end of their shelf life, determining the load of enterobacteriaceae, total mesophilic microflora, psychrotrophic microflora, lactic acid microflora, Staphylococcus spp. and L. monocytogenes in the samples. Also, they have been determined the changes in organoleptic properties, and pH. With the packaging technology using laminar flow a greater proportion of product just packaged with counts less than 10 UFC/g is obtained, and, in all the cases, sliced meat samples with counts less than of 104 UFC/g were observed in cooked ham, and less than 103 CFU/g were observed in cooked turkey meat. This significant diminution of microbial load in the product just packaged results in a clear increase of its shelf life at 4ºC, extending it from 18,6 days to 35 days in the case of sliced cooked ham, and from 32,3 to 49,2 days in the case of sliced cooked turkey meat

Efectividad de desinfectantes de superficies de los equipos en instalaciones de envasado de productos listos para su consumo

[SPA] Una de las principales fuentes de contaminación de los alimentos envasados listos para su consumo son las superficies de los equipos en contacto con los alimentos. En dichas superficies se desarrollan biofilms que con frecuencia son muy resistentes a los agentes desinfectantes utilizados en las plantas de fabricación. En este trabajo se han aislado diferentes microorganismos de biofilms en superficies de equipos, y se han estudiado frente a desinfectantes comerciales utilizados en diversas industrias alimentarias, en un equipo multiskan ascent y placas microtiter. Se estudiaron tres cepas bacterianas que pueden ser encontradas en las superficies de los equipos: Pseudomonas sp., Escherichia coli y Listeria monocytogenes. Los desinfectantes ensayados han sido quacide p40, dectocide yo2, dexacide b10, divosan activ, quacide mc7, limoseat, asep 150 y destocide. Respecto a las determinaciones de concentración minina inhibitoria (cmi) los desinfectantes mas efectivos resultaron ser quacide mc7, que a una concentración de 0.125 % v/v inhibió el crecimiento de todas las cepas diana y asep 150 que produjo el mismo efecto a una concentración de 0,06%. La definición de concentración mínima bactericida (cmb) se estableció como el valor de concentración del desinfectante que destruye una población de 104 cel./ml durante 20 min. Las cmb más bajas se obtuvieron con dexacide b10 con cmb = 0,125% para todas las cepas estudiadas y quacide mc7 con cmb = 0,0625% para l. Monocytogenes y e. Coli y de cmb =0,125% para Pseudomonas sp. Como conclusión se recomienda utilizar una alternancia de desinfectantes dependiendo del tipo de cepa predominante que contamine la superficie de los equipos. [ENG] The main contamination sources of packaged ready to eat products are equipment surfaces which keep in touch with them during the production process. Microbial biofilms are developed on these surfaces and frequently they are resistant to common disinfectants used in the food industry. Different spoilage microorganisms which usually are found on equipment surfaces biofilms have been tested in the present work. Their resistance against comercial disinfectants was studied in a Multiskan Ascent spectrophotometer and microtitter plates (96 wells). Three strains isolated from the equipment surfaces were tested: Pseudomonas sp., Escherichia coli y Listeria monocytogenes. Disinfectants were Quacide P40, Dectocide YO2, Dexacide B10, Divisan activ, Quacide MC7, Limoseat, Asep 150 y Destocide. The minimal inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) were determined for each strain. The most effective disinfectants regarding the MIC values were Quacide MC7 and Asep 150 which inhibited the growing of the target strains at concentrations of 0,125 and 0,06 % v/v respectively. The MBC was defined as the minimal concentration at which the strain population of 104 cell/ml was killed during 20 minutes of interaction between the strain and each disinfectant. The lowest values of MBC were 0,125 % v/v with Dexacide B10 for all the target strains and 0,0625 % v/v with Quacide MC7 for L. monocytogenes and E.coli and 0,125 % v/v for Pseudomonas sp. As conclusion we recommend the use of a disinfection plan in relation to the predominant spoiling microflora and the potential risk that represents for the food product. This plan would include several disinfectants changing them each few days

The application of essential oil vapors at the end of vacuum cooling of fresh culinary herbs promotes aromatic recovery

Aroma is an important quality parameter of fresh culinary herbs that may be highly affected after postharvest treatments. The innovative technology of vapor essential oil (EO) application under vacuum conditions may recover aroma lost during the postharvest processing of plant products like aromatic herbs. Hence, this study assessed the aroma recovery effect of vapor EOs applied during vacuum cooling on curly parsley and dill. The volatile organic compounds (VOCs) profiles of these aromatic herbs were studied by static headspace solid-phase microextraction (SPME), and the VOCs sorption kinetics onto the SPME stir-bar coating were modeled by the Baranyi model. At the pilot plant scale, the total VOCs contents of parsley and dill (whose extractability was increased by 10–20% after a single vacuum process) were enhanced by 4.5-and 2-fold, respectively, when vapor EOs were applied. In particular, 1,3,8-p-menthatriene and carvone (parsley) increased by 18.7-and 7.3-fold, respectively, while dill ether (the characteristic VOC of dill) augmented by 2.4-fold after vapor EOs were applied under vacuum conditions. The aroma recovery of culinary herbs was successfully validated at an industrial level in an installation developed by our group to apply vapor EOs within a vacuum cooling system, reaching total VOC recoveries of 4.9-and 2.3-fold in parsley and dill, respectively.</p

Synergistic Antimicrobial Activities of Combinations of Vanillin and Essential Oils of Cinnamon Bark, Cinnamon Leaves, and Cloves

Plant bioactive compounds have antimicrobial and antioxidant activities that allow them to be used as a substitute for synthetic chemical additives in both food and food packaging. To improve its sensory and bactericidal effects, its use in the form of effective combinations has emerged as an interesting possibility in the food industry. In this study, the antimicrobial activities of essential oils (EOs) of cinnamon bark, cinnamon leaves, and clove and the pure compounds vanillin, eugenol, and cinnamaldehyde were investigated individually and in combination against Listeria monocytogenes and Escherichia coli O157:H7. The possible interactions of combinations of pure compounds and EOs were performed by the two-dimensional checkerboard assay and isobologram methods. Vanillin exhibited the lowest antimicrobial activity (MIC of 3002 ppm against L. monocytogenes and 2795 ppm against E. coli O157:H7), while clove and cinnamon bark EOs exhibited the highest antimicrobial activity (402–404 against L. monocytogenes and 778–721 against E. coli O157:H7). For L. monocytogenes, pure compound eugenol, the main component of cinnamon leaves and clove, showed lower antimicrobial activity than EOs, which was attributed to the influence of the minor components of the EOs. The same was observed with cinnamaldehyde, the main component of cinnamon bark EO. The combinations of vanillin/clove EO and vanillin/cinnamon bark EO showed the most synergistic antimicrobial effect. The combination of the EOs of cinnamon bark/clove and cinnamon bark/cinnamon leaves showed additive effect against L. monocytogenes but indifferent effect against E. coli O157:H7. For L. monocytogenes, the best inhibitory effects were achieved by cinnamon bark EO (85 ppm)/vanillin (910 ppm) and clove EO (121 ppm)/vanillin (691 ppm) combinations. For E. coli, the inhibitory effects of clove EO (104 ppm)/vanillin (1006 ppm) and cinnamon leaves EO (118 ppm)/vanillin (979 ppm) combinations were noteworthy. Some of the tested combinations increased the antimicrobial effect and would allow the effective doses to be reduced, thereby offering possible new applications for food and active food packaging

Antioxidant and Antimicrobial Effect of Plant Essential Oils and Sambucus nigra Extract in Salmon Burgers

The antioxidant capacity of oregano (OEO) and clove (CLEO) essential oils and black elderberry (Sambucus nigra) flower extract (SNE) were compared with butylhydroxytoluene (BHT) regarding its protection against lipid peroxidation and microbial counts in salmon burgers stored at 4 °C for 14 days and after cooking. The content of total phenols was 5.74% in OEO, 2.64% in CLEO and 2.67 % in the SNE. The total phenolic content and the antioxidant capacity were significantly higher (p &lt; 0.05) for SNE and OEO. Both essential oils showed a similar IC50 and inhibition percentage of lipid peroxidation to BHT. The combination of OEO and SNE reduced 29% of thiobarbituric acid reactive substances (TBARS), while BHT reduced 31% of TBARS generated during refrigeration storage in salmon burgers in relation to the control sample without antioxidants. Additionally, the microbial counts after 14 days of refrigeration were the lowest in burgers when the combination of OEO and SNE was used. This study concludes that OEO and SNE can be used as inhibitors of lipid oxidation in salmon products and as natural candidates to replace commonly used synthetic antioxidants and antimicrobials in these food products

Packaging of Fresh Sliced Mushrooms with Essential Oils Vapours: A New Technology for Maintaining Quality and Extending Shelf Life

The use of vapour of essential oils (EOs) through an innovative pilot-plant packaging device was studied to preserve the quality of sliced mushrooms during storage. A mix of EOs (eugenol, bergamot EO, and grapefruit EO) was vaporized (100 and 125 µL L−1) and applied during packaging of sliced mushrooms under modified atmosphere packaging (MAP); then, the product quality was studied during cold storage up to 12 days. The highest colour changes of EOs125 samples, which were observed in the mushroom stipe, were not observed with the EOs100 atmosphere. Thus, the high polyphenoloxidase activity observed in untreated samples after 5–7 days was highly controlled with the vapour EOs atmospheres. Furthermore, the visual appearance scores of EOs100 samples were still over the limit of usability, while untreated samples were already below this threshold after 5 days of storage. A strong bacteriostatic effect was achieved with vapour EOs, reducing the Pseudomonas spp. (the main microbial genus in cultivated mushrooms) growth by ≈1.7 log CFU g−1, regardless of the EOs dose, after 12 days. The activity of phenyl ammonia lyase was also reduced up to ≈0.4 enzymatic units with the EOs100 treatment. Conclusively, packaging of sliced mushrooms under an atmosphere enriched with 100 µL L−1 EOs vapour highly controlled the quality loss of sliced mushrooms owing to their enzymatic inhibition and high bacteriostatic effect