Search

[EN] The effect of drying temperature and the application of ultrasound on drying kinetics of Lawsonia inermis (henna) leaves and the extraction of lawsone from the dried samples was addressed. Indeed, henna leaves were dried with and without the application of ultrasound (21.7 kHz, 30.8 kW/m3) at 40, 50 and 60 C with a constant air velocity (1 m/s). As expected, both the increase of temperature and the application of ultrasound decreased the drying time and increased the rate of extraction of the lawsone. The values of the effective diffusion coefficients obtained were used to quantify this influence showing the value increases with higher drying temperature and the application of ultrasound. Moreover, the influence of temperature was quantified by the estimation of the activation energy from an Arrhenius-type equation (46.25 kJ/mol in the case of drying without ultrasound application and 44.06 kJ/mol in the case of ultrasonically-assisted drying). Regarding the influence of studied variables on lawsone extraction yield, the higher is the temperature, the lower is the yield, probably linked with lawsone degradation reaction due to thermal treatment. On the contrary, the application of ultrasound improved the extraction yield mainly at the lower drying temperature tested of 40 C.

[EN] Improving the actual acid hydrolysis of cassava bagasse (CB) with the assistance of high-intensity ultrasound (US) was aimed in comparison with mechanical agitation (AG). The kinetics of reducing and total sugar release were mathematically modeled. The acoustic field characterization and apparent viscosity of the suspensions were correlated. Moreover, microscopic analyses (visible, fluorescence and polarized light) were carried out to identify changes produced by the treatments. Both AG and US-treatments showed themselves to be effective at hydrolyzing CB. However, US-experiments reached equilibrium in the reducing sugar release process earlier and obtained slightly higher values of total sugars released. The Naik model fitted the experimental data with good accuracy. A greater loss in the birefringence of the starch granules and the degradation of lignocellulosic matter was also observed in US-assisted hydrolysis. The actual acoustic power applied was reduced after hydrolysis, probably due to the increase in the apparent viscosity of the resulting suspensions.

[EN] The effects produced by high-intensity ultrasound application during the acid pretreatment of biomass can enhance its later conversion into bioethanol. Therefore, it is interesting to evaluate how residues,such as cassava bagasse (CB), affect the actual acoustic field applied and, thus, the magnitude of its effects. For this, calorimetric method was used to estimate acoustic energy and the efficiency of electric-acoustic energy conversion in acid suspensions containing different CB concentrations (2¿10%). Tests were carried out under different input powers, from 160 to 400 W (24 kHz), at different distances (1.5¿5.5 cm) from the sonotrode. Thus, the experimental acoustic intensity measured varied from 12.90 to 68.57 W/cm2, the highest values being registered in the suspensions with the lowest CB content (65.55¿36.81% of conversion yield close to the sonotrode). Attenuation was also addressed during sound wave propagation, finding a constant value of 0.021 cm-1. Polynomial models were well fitted to acoustic parameters and acoustic intensity exhibited a high correlation (r>0.87 and pvalue < 0.05) with the experimental thermophysical properties of the suspensions.

This is an Author's Accepted Manuscript of an article published in Ronaldo E. Mello, Alessia Fontana, Antonio Mulet, Jefferson Luiz, G. Correa & Juan A. Cárcel (2020) Ultrasound-assisted drying of orange peel in atmospheric freeze-dryer and convective dryer operated at moderate temperature, Drying Technology, 38:1-2, 259-267, DOI: 10.1080/07373937.2019.1645685 [copyright Taylor & Francis], available online at: http://www.tandfonline.com/10.1080/07373937.2019.1645685, [EN] Atmospheric freeze-drying (AFD) at -10 degrees C and moderate temperature convective drying (MTD) at 50 degrees C without and with ultrasound application (20.5 kW/m(3)) were carried out. Alcohol insoluble residue (AIR) and its swelling capacity (SC), water retention capacity (WRC) and fat retention capacity (FRC) were measured in the dried product. Ultrasound significantly shortened the drying time in both processes, the intensification effect being more significant in atmospheric freeze-drying (57% and 27% reduction in atmospheric freeze-drying and convective drying, respectively). As regards AIR and WRC, no effect was observed of either the drying temperature or ultrasound application. On the contrary, SC was significantly lower in AFD samples. The FRC of MTD samples was similar to that of the fresh ones and higher than the values obtained for atmospheric freeze-dried samples. Therefore, convective drying at moderate temperature preserved the AIR properties better than atmospheric freeze-drying.

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Drying Technology on 2019, available online at: http://www.tandfonline.com/10.1080/07373937.2018.1474476, [EN] Increasing the value of the waste generated by food processing is a must from an environmental and economic point of view. This paper addresses the influence of drying temperature and ultrasound application on the drying kinetics and quality of apple peel (Royal Gala var.). Samples were dried at -10, 30, 50 and 70 ºC without and with (50 W) ultrasound application. Color, antioxidant capacity, total phenolic and ascorbic acid content were measured. Ultrasound application and drying temperature significantly shortened the drying time and affected the quality parameters. The drying carried out at 30 ºC with ultrasound application was a fast process that provided samples with good color and antioxidant attributes.

[EN] Understanding the characterization and rheological behavior of acid suspensions of cassava bagasse provides essential information for the design of conversion processes. Samples with different cassava bagasse concentrations (0-10% w.w-1), phosphoric acid (0-10% w.w(-1)) at temperatures between 278.13 and 318.13 K were submitted to steady-state flow over a wide range of shear rates (1-265 s(-1)). The biomass particles had considerable residual starch (similar to 50% db), low lignin content and adequate particle size (<200 mu m) for the conversion process. Flow curves were well-fitted to the Herschel-Bulkley model, presenting a Newtonian domain at low solids and acid content and a non-Newtonian behavior with noticeable yield stress and shear-thinning characteristic (n < 1) at above 6% of cassava bagasse. Resistance to flow increased as the solids loading and acid content increased. Temperature dependence could be expressed as a function of an Arrhenius-type equation with good accuracy of fit. (C) 2019 Elsevier B.V. All rights reserved.

This is an Author's Accepted Manuscript of J. A. Cárcel, D. Castillo, S. Simal & A. Mulet (2019) Influence of temperature and ultrasound on drying kinetics and antioxidant properties of red pepper, Drying Technology, 37:4, 486-493, DOI: 10.1080/07373937.2018.1473417 [copyright Taylor & Francis], available online at: http://www.tandfonline.com/10.1080/07373937.2018.1473417, [EN] Red pepper samples (1 m/s) were dried at different temperatures (30, 50, 70 degrees C) without and with (20.5 kW/m(3); 21.7 kHz) ultrasound application. The antioxidant capacity (AC), the total phenolic content (TPC), and the ascorbic acid (AA) content of fresh and dried red pepper samples were used as indicators of the quality of the dried products. Ultrasound application significantly improved the kinetics in every case, influencing not only the effective diffusivity but also the mass transport coefficient thus implying a reduction in energy needs. Drying significantly reduced AC, TPC, and AA, this reduction being significantly smaller at 70 degrees C due to the shorter drying time. Compared with conventional drying, ultrasound application reduced the loss of antioxidant properties at 50 degrees C but produced greater degradation at 70 degrees C, which points toward an optimal drying temperature when using ultrasound.

[EN] The study of sugar release kinetics is an essential step prior to developing new technologies for applying in the bioethanol industry. To this end, the kinetics of reducing and total sugar release (extraction/hydrolysis) from artichoke waste were obtained in different conditions to evaluate the solubility of free sugars from raw matter and the hydrolysis of larger chain molecules separately. Thus, experiments of extraction with water (WE), hydrolysis (HY) in acid solutions and a conventional industrial hydrolysis (IHY), which combines dissolution and hydrolysis effects, were carried out. All of the treatments were studied with ultrasound application (US) or with conventional agitation (AG). Compared to AG experiments, US application accelerated the sugar dissolution reducing 50% the time to reach the equilibrium. The decrease in the biomass concentration in the suspensions increased the US effects in HY experiments. In IHY experiments, US was also able to enhance the final yield of sugars achieving relative reducing sugar and total sugar amounts 213% and 175%, significantly higher than AG experiments. The Theological changes in the suspensions during treatments can explain the different magnitude of ultrasound effects. The acoustic field characterization and the measurement of viscosity in the acid suspensions agreed with these results.

[EN] The feasibility of using supercritical CO2 assisted by ultrasound (SC-CO2-HPU) in continuous mode (3.06 min residence time) for the non-thermal pasteurization of orange juice was evaluated. The proposed technology was effective for microbial inactivation; complete inactivation was obtained for E. coli and total aerobic mesophilic bacteria while 99.7% reduction for S. cerevisiae. Results showed that the SC-CO2-HPU treatment brought about small changes in the pH, Brix and titratable acidity of the juice. Furthermore, although SC-CO2-HPU technology produced a higher browning index (211%) and greater changes in color, it was possible to improve the cloud of juice by 173%; what is more, a smaller percentage of phenolic compounds (6.5%) and ascorbic acid (5.5%) was lost compared to the thermally pasteurized juice (10% decrease in both parameters). Moreover, the antioxidant capacity could be increased (12%) with respect to the natural juice. Therefore, SC-CO2-HPU technology appears to be effective for microbial pasteurization and the mild process conditions used could lead to an increase in the juice quality. Industrial relevance: The demand for high quality processed foods which preserve their natural and fresh-like characteristics has awakened a growing interest in non-thermal technologies. The ultrasound-assisted SC-CO2 continuous system is an innovative non-thermal technology that could represent a development in the area of emerging technologies. This technology allows high quality products to be obtained by preserving their natural bioactive compound content while maintaining their fresh-like organoleptic characteristics. In fact, food experts working in academia, industry or governmental agencies worldwide foresee that non-thermal emerging technologies will be among the most impactful novel food processing technologies for the next decade in terms of product commercialization.

[EN] Supercritical carbon dioxide inactivation technology represents a promising nonthermal processing method, as it causes minimum impact on the nutritional food properties. The aim of this study was to analyze the combined effect of supercritical carbon dioxide and high-power ultrasound on the inactivation of natural microbiota and the quality attributes of pineapple juice treated in a continuous flow system. Different juice residence times (3.06-4.6min), at 100bar and 31.5?, were used. The results indicated that the microbiota inactivation was complete and the differences obtained in the quality attributes (2.2% for pH, 4.8% for degrees Brix, 2% for vitamin C) were minimal. During storage, microorganisms were not able to recover and the vitamin C decrease could be limited to 8.2% after four weeks. The results demonstrated that the supercritical carbon dioxide-high-power ultrasound technique could be an excellent alternative for the cold pasteurization of pineapple juice.

[EN] This work presents the development of a probiotic dried apple snack consisting of dried apple cubes impregnated with Lactobacillus casei NRRL B-442. Apple cubes were impregnated with probiotic microorganisms and dried under different temperatures (10-60 degrees C), with or without application of ultrasound. The viability of Lactobacillus casei in the dried apple snack was evaluated studying the effects of drying conditions and ultrasound application (as a drying enhancing technology). A mathematical model was developed to predict the drying kinetics and the inactivation of Lactobacillus casei. Drying and microorganism inactivation rates increased with increasing process temperature and with ultrasound application. The concentration of probiotics in the apple snacks was similar to the concentration of microorganisms in commercial probiotic dairy products when the apples were dried at 60 degrees C or when ultrasound-assisted air-drying was applied, thus proving that the production of dried probiotic apple snacks is possible and technically viable.

The institutional organizers of IDS 2018 are the Department of Food Technology at the Universitat Politècnica de València and the Department of Chemistry at the University of Illes Balears. Like its previous biannual IDS conferences, the objective of 21th IDS is to provide the most advanced and comprehensive global forum for disseminating results and data in research, development, and applications in drying/dewatering sciences and technologies.This Symposium will be held in the main campus of the Universitat Politècnica de València and aims to bring together leading researchers and engineers from academia and from industry from all around the world in this university environment. It is also planned during the meeting an exposition of industrial equipment and developments. An Award program will be also part of the event for the international drying community. This Symposium is the 21th event in the series founded by Professor Arun S. Mujumdar at McGill University, Montreal, Canada, in 1978

Tesis por compendio, Thermal treatments are used to extend the shelf life of food. However, these methods, which use high temperatures, may alter the sensory and nutritional properties of food. Therefore, along with the demand of consumers of fresh and natural foods, there is an increasing interest in non-thermal preservation techniques. The aim of these new technologies is to ensure the preservation of food while maintaining its nutritional value and organoleptic properties. An example of these methods is given by the use of supercritical CO2 (SC-CO2). Different authors have reported the inactivation of enzymes and microorganisms as a result of SC-CO2. Moreover, this technique minimally alters the sensory and nutritional properties of foods. On the other hand, the use of supercritical fluids assisted with high power ultrasound (HPU) allows vigorous agitation and a rapid dissolution of CO2 into the medium. Consequently, the rate of the inactivation mechanisms associated with supercritical CO2 also increases. This technology has been mainly developed in a discontinuous system presenting important reductions on the time of microbial inactivation compared to using only supercritical fluids. However, the food industry requires continuous systems to process large quantities of product. In this context, the main purpose of the present Doctoral Thesis was to develop and apply a continuous system for the inactivation of microorganisms using supercritical fluids assisted with high power ultrasound (SC-CO2-HPU). Both, the microbial inactivation capacity of the technique and the effect of treatments on food quality were assessed. The first stage of the project consisted on the retrofitting of a system for the inactivation of microorganisms that combines the use of supercritical fluids (SC-CO2) and ultrasound to convert its discontinuous (or batch) operation system into a continuous system. The second stage of the project consisted on the analysis of the effect of the pressure, temperature and resi, Para prolongar la vida útil de los alimentos se utilizan diferentes técnicas de conservación, siendo tradicionalmente los tratamientos térmicos los más empleados. Sin embargo, estas técnicas que emplean altas temperaturas, alteran las propiedades sensoriales y nutricionales del alimento. Por ello, y junto a la demanda de los consumidores de alimentos frescos y naturales, existe un creciente interés por las técnicas de conservación no térmicas. El objetivo de estas nuevas tecnologías es asegurar la conservación de alimentos, manteniendo su valor nutricional y propiedades organolépticas. El uso de CO2 en estado supercrítico (SC-CO2) es una de estas tecnologías. El SC-CO2 ha sido reseñado por diferentes autores en la inactivación de enzimas y microorganismos, alterando mínimamente las propiedades sensoriales y nutricionales de los alimentos. Por otra parte, el uso de fluidos supercríticos asistidos con ultrasonidos de potencia (HPU) permite una vigorosa agitación del medio, una rápida disolución del CO2 en el medio y por tanto un aumento en la velocidad de los mecanismos de inactivación asociados al CO2 supercrítico. Dicha tecnología ha sido desarrollada en un sistema en discontinuo, presentando importantes reducciones en el tiempo de inactivación microbiana, comparado con el uso solo de fluidos supercríticos. Sin embargo, en la industria alimentaria se precisa de sistemas en continuo que permitan procesar grandes cantidades de producto. En este contexto, el objetivo principal de la presente Tesis Doctoral fue desarrollar y aplicar un sistema de inactivación de microorganismos en continuo, empleando fluidos supercríticos asistidos con ultrasonidos de potencia (SC-CO2-HPU). La primera etapa del proyecto consistió en la adaptación del sistema de inactivación de microorganismos mediante fluidos supercríticos (SC-CO2) y ultrasonidos (HPU) para convertir su funcionamiento de discontinuo a continuo. La segunda etapa consistió en analizar el efecto de la presión, temperatura, Per a perllongar la vida útil dels aliments s'utilitzen diferents tècniques de conservació, sent tradicionalment els tractaments tèrmics els més emprats. No obstant açò, aquestes tècniques que empren altes temperatures, alteren les propietats sensorials i nutricionals de l'aliment. Per açò, i al costat de la demanda dels consumidors d'aliments frescos i naturals, existeix un creixent interès per les tècniques de conservació no tèrmiques. L'objectiu d'aquestes noves tecnologies és assegurar la conservació d'aliments, mantenint el seu valor nutricional i propietats organolèptiques. L'ús de CO2 en estat supercrític (SC-CO2) és una d'aquestes tecnologies. El SC-CO2 ha sigut ressenyat per diferents autors en la inactivació d'enzims i microorganismes, alterant mínimament les propietats sensorials i nutricionals dels aliments. D'altra banda, l'ús de fluids supercrítics assistits amb ultrasons de potència (HPU) permet una vigorosa agitació del medi, una ràpida dissolució del CO2 en el medi i per tant un augment en la velocitat dels mecanismes de inactivació associats al CO2 supercrític. Aquesta tecnologia ha sigut desenvolupada en un sistema en discontinu, presentant importants reduccions en el temps de inactivació microbiana, comparat amb l'ús sol de fluids supercrítics. No obstant açò, en la indústria alimentària es precisa de sistemes en continu que permeten processar grans quantitats de producte. En aquest context, l'objectiu principal de la present Tesi Doctoral va ser desenvolupar i aplicar un sistema d'inactivació de microorganismes en continu, emprant fluids supercrítics assistits amb ultrasons de potència(SC-CO2-HPU). S'avaluarà tant la capacitat d'inactivació microbiana de la tècnica com l'efecte dels tractaments sobre la qualitat dels aliments. La primera etapa del projecte va consistir en l'adaptació del sistema de inactivació de microorganismes mitjançant fluids supercrítics (SC-CO2) i ultrasons (HPU) per a convertir el seu funcionament de discontinu a continu.

[EN] The great amount of waste produced by the food industry can be an interesting source of bioactive compounds. To this end, convective drying is one of the most extended method to stabilize the industrial by-products. However, drying conditions can affect not only drying kinetics but also the bioactivy of some compounds. Apple skin constitutes one of the main by-product generated in apple juice or cider production. It contains important amounts of functional compounds such as polyphenols or vitamin C whose extraction can be interesting. The main aim of this work was to determine the influence of drying conditions, temperature and application of ultrasound, in some quality parameters of dried apple skin. For this purpose, apple skin samples were dried at different temperatures (-10, 30, 50 and 70 ºC) and with (20.5 kW/m3) or without application of ultrasound. Color, total phenolic content, antioxidant activity and vitamin C was measured in fresh and dried samples. The increase of drying temperature and the ultrasound sligthly reduced the antioxidant properties of samples while no influence in sample color was observed.

[EN] In this work the influence of some process variable on drying rate of henna leaves was studied. For this reason, henna leaves were dried (1 m/s) with and without ultrasound application at three temperatures, 40, 50 and 60 °C. As can be expected, the higher the temperature the faster the drying process. Ultrasound application increase drying rate at every temperature tested. Drying kinetics were modeled by using different experimental models. Weibull model provided the best fit for henna leaves drying kinetics.

This is an Author's Accepted Manuscript of an article published in Drying Technology, 36, 15, 1814-1823 © Taylor & Francis, available online at: http://doi.org/10.1080/07373937.2017.1417870, [EN] The aim of this work was to evaluate the feasibility of using power ultrasound to improve the atmospheric freeze-drying of mushroom, as interesting alternative to vacuum freeze-drying, considering not only kinetic effects but also the final quality. For that purpose, mushroom slices (Agaricus bisporus) were dried (¿10°C and 2 m/s) with (24.6 and 12.3 kW/m3; 21.9 kHz) and without ultrasound application. The application of ultrasound significantly influenced the drying kinetics, increasing the effective diffusivity up to 280% and shortening drying time up to 74%. As for the quality parameters (color, texture, rehydration, and cell damage), no remarkable influence of the ultrasound application was observed. Therefore, the application of power ultrasound during the atmospheric freeze-drying of mushroom might be considered as an interesting technology providing that it significantly increased the process kinetics without greatly affecting the quality of the final product.

[EN] Ultrasound application represents an alternative means of improving heat and mass transfer. This study explored the combined application of ultrasound (US) during both the osmotic dehydration (OD) pretreatment and the convective drying of pineapple. For that purpose, fresh and pretreated samples (20 or 40 min, with (55.5 kW/m3, 40 kHz) and without ultrasound application) in an osmotic solution of sucrose (40% w/w) were dried (40 °C and 70 °C) with (21.8 kHz, 31 kW/m3) and without ultrasound application. A diffusion model permitted to quantify the influence of the factors studied (time of pretreatment, ultrasound application during pretreatment, drying temperature and ultrasound application during drying) in drying kinetics. The increase in drying temperature and the application of ultrasound during drying significantly accelerated the drying process by reducing both the internal and the external mass transport resistance. On the contrary, the osmotic pretreatments reduced the drying rate by increasing the external resistance.

[EN] Atmospheric freeze drying is a highly attractive process for the dehydration of thermosensitive products, like food, due to the fact that water is removed at low temperature by sublimation. Unfortunately, drying times can be very long because of the internal resistance of the product to vapor diffusion: power ultrasound can be an effective means of accelerating the process, thus reducing the operating cost. The aim of this study was to assess the effect of air temperature and velocity, ultrasound power and sample size on the drying kinetics of eggplant (Solanum melongena L.) samples and, afterward, to analyze in silico an industrial process. Experiments were performed under various conditions regarding air temperature (¿5, ¿7.5, ¿10°C), velocity (2 and 5¿m¿s¿1), power ultrasound (0, 10.3, 20.5¿kW¿m¿3, 21.9¿kHz), and sample size. Drying rate was measured experimentally. The air velocity showed no relevant effects on the drying kinetics, and the effect of air temperature was slight when compared to the marked reduction in the drying time obtained when ultrasound was applied. The uniformly retreating interface model was modified to account for the cubic shape of the samples and used to establish the kinetic parameters, in particular to evaluate water diffusivity in the dried product, searching for the best fit between measured and calculated moisture content. The model was finally used to optimize the process in silico, considering an industrial unit as test case. In this case, it appeared that power ultrasound can increase the productivity of a tunnel dryer up to four or five times, and it allows the operational and fixed costs of the plant to be reduced significantly.

[EN] The aim of this work was to address the air-borne application of power ultrasound in the convective drying of grape skin, a by-product of winemaking. For that purpose, convective drying experiments were carried out on red grape skin at 40, 50, 60 and 70 C with (21.7 kHz, 45 W) and without power ultrasound application. The kinetic intensification was evaluated by modeling the drying kinetics using empirical and diffusion models. Meanwhile, the quality of the dried product was determined by obtaining ethanolic extracts and assessing the total phenolic content and antioxidant capacity by means of the FRAP method. Moreover, individual polyphenols were identified by HPLC-DAD-ESI-MS/MS and a Partial Component Analysis (PCA) was performed in order to elucidate the relationships between the measured variables that were related to bioactive content. Both temperature and ultrasound application had a significant (p < 0.05) influence on the drying kinetics, which were satisfactorily described by both the Peleg and diffusion models. In addition, both factors significantly (p < 0.05) influenced the total phenolic concentration and antioxidant capacity of the extracts. Ultrasound application reduced the antioxidant potential, probably due to oxidase activation and cell degradation. Bioactive potential, on the other hand, was increased as a consequence of hightemperature drying, leading in particular to a greater release of malvidin 3-O-b-D-galactoside.

[EN] The aim of this study was to evaluate the effect of temperature and ultrasound application on drying kinetics and antioxidant potential of passion fruit peel. To this end, drying experiments (1 ms1) were carried out at 40, 50, 60 and 70 C without and with ultrasound application (21,7 kHz, 30.8 kW/m3). Two diffusion models based on Fick's second law were used to mathematically describe the drying kinetics considering or not the external moisture transport resistance. The antioxidant capacity and the total phenolic content of dried passion fruit peels were assessed. The increase in temperature and the application of ultrasound significantly reduced the drying time. Modeling showed that the application of ultrasound increased both the effective diffusivity and the mass transfer coefficient, particularly at the mildest temperatures tested, 40 and 50 C. Under these conditions, ultrasound application also reduced the loss of total phenolic content and maintained the antioxidant activity of dried passion fruit peel.

[EN] Low-temperature drying (LTD) constitutes an interesting means of dehydrating foodstuffs, thus preserving the quality of the product. Power ultrasound (US) generates several mechanical effects that could help to shorten the long drying times associated with LTD. In this work, the feasibility of using US in LTD of desalted cod was assessed. For this purpose, desalted cod slices (50 30 5 mm) were dried (2 m/s) at different temperatures (10, 0 and 10 C) without (AIR) and with (AIR þ US, 20.5 kW/m3) US application. Afterwards, the dried samples were rehydrated in distilled water (25 C). A diffusion model was used to describe both drying and rehydration kinetics. The color and hardness of both dried and rehydrated cod samples were also measured. The application of US increased the drying rate at every temperature tested, shortening the drying time by 16% at 0 C and up to 60% at 10 C. The ultrasonically assisted dried samples presented a rehydration rate which was slightly lower than that of those that had been conventionally dried, but they were harder and whiter, which is more suited to consumer preferences. Therefore, power ultrasound could be considered an affordable technology with which to accelerate LTD of desalted cod, providing high quality dried products.

[EN] Laboratory continuous regime equipment was designed and built for supercritical CO2 microbial inactivation assisted by high power ultrasound (SC-CO2-HPU). Apple juice, previously inoculated with 1-10x107 CFU/ml of Saccharomyces cerevisiae, was treated in the equipment at different juice residence times (3.06-9.2 min), temperatures (31-41 °C) and pressures (100-300 bars). Inactivation ratios were fitted to a hybrid (boolean-real) model in order to study the effect of the process variables. The maximum inactivation achieved by the system was 7.8 log-cycles. The hybrid model demonstrated that HPU has a significant effect on inactivation after shorter residence times. A multi-objective optimization performed with the hybrid model showed that 6.8 log cycles of inactivation could be obtained after a minimum residence time (3.1 min) with HPU application, whereas under the same conditions but without HPU, the inactivation would be 4.3 log-cycles. Therefore, the ultrasound assisted continuous system has shown a great potential for microbial inactivation using SC-CO2 under mild process conditions.

[EN] The daily challenge involved in operating a process is the attainment of the objectives. Process management requires the use of tools adapted to the system s complexity. In order to obtain real time results, simplified mechanistic modeling offers a way to deal with this. To this end, carob pod (Ceratonia siliqua, L.) kibbles extraction is addressed in this work. They are a source of different, valuable components and have a complex structure and a highly variable concentration of components. The components considered are sugars and soluble polyphenols. Obtaining the extracts with an optimal composition of a particular component, while avoiding or limiting other components in the extract, is a challenge to be addressed. Two steps can be considered: solubilization and diffusion, modeled by means of a first order reaction and by considering slab geometry. The optimal processing time and temperature are obtained by taking a particular kibble size and composition into account

Atmospheric freeze drying consists of a convective drying process using air at a temperature below the freezing point of the processed product, and with a very low relative humidity content. This paper focuses on the use of a simple one-dimensional model considering moving boundary vapor diffusion to describe the ultrasonic assisted atmospheric freeze-drying of foodstuffs. The case study is the drying of apple cubes (8.8 mm) at different air velocities (1, 2, 4 and 6 m/s), temperatures ( 5, 10 and 15 C), without and with (25, 50 and 75 W) power ultrasound application. By fitting the proposed diffusion model to the experimental drying kinetics, the effective diffusivity of water vapor in the dried product was estimated. The model was successfully validated by drying apple samples of different size and geometry (cubes and cylinders). Finally, a 23 factorial design of experiments revealed that the most relevant operating parameter affecting the drying time was the applied ultrasound power level.

Meat industry demands non-destructive techniques for the control of the salting process to achieve a homogeneous final salt content in salted meat products. The feasibility of using low-intensity ultrasound for characterizing the salting process of pork meat products was evaluated. The ultrasonic velocity (V) and time of flight (TF) were measured by through-transmission and pulse-echo methods, respectively, in salted meat products. Salting involved an increase of the V in meat muscles and a decrease of the time of flight in whole hams. Measuring the V before and after salting, the salt content could be estimated. Moreover, online monitoring of the salting process by computing the TF could be considered a reliable tool for quality control purposes

A method combining supercritical carbon dioxide (SC-CO2) and high power ultrasound (HPU) has been developed and tested for microbial/enzyme inactivation purposes, at different process conditions for both liquid and solid matrices. In culture media, using only SC-CO2, the inactivation rate of E. coli and S. cerevisiae increased with pressure and temperature; and the total inactivation (7-8 log-cycles) was attained after 25 and 140 min of SC-CO2 (350 bar, 36 ºC) treatment, respectively. Using SC-CO2+HPU, the time for the total inactivation of both microorganisms was reduced to only 1-2 min, at any condition selected. The SC-CO2+HPU inactivation of both microorganisms was slower in juices (avg. 4.9 min) than in culture media (avg. 1.5 min). In solid samples (chicken, turkey ham and dry-cured pork cured ham) treated with SC-CO2 and SC-CO2+HPU, the inactivation rate of E. coli increased with temperature. The application of HPU to the SC-CO2 treatments accelerated the inactivation rate of E. coli and that effect was more pronounced in treatments with isotonic solution surrounding the solid food samples. The application of HPU enhanced the SC-CO2 inactivation mechanisms of microorganisms, generating a vigorous agitation that facilitated the CO2 solubilization and the mass transfer process. The cavitation generated by HPU could damage the cell walls accelerating the extraction of vital constituents and the microbial death. Thus, using the combined technique, reasonable industrial processing times and mild process conditions could be used which could result into a cost reduction and lead to the minimization in the food nutritional and organoleptic changes

© 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the Scientific Committee of ICU 2015, [EN] The atmospheric freeze drying (AFD) constitutes an interesting alternative to vacuum freeze drying providing products with similar quality at lowest cost. However, the long process time needed represent an important drawback. In this sense, the application of high intensity ultrasound can enhance heat and mass transfer and intensify the operation. In hot air drying operation, the ultrasonic effects are dependent on the process variables such as air velocity, internal sample structure or ultrasonic power applied. However, in AFD processes, the internal structure of material or the air velocity has not significant influence on the magnitude of ultrasonic effects. The aim of this work was to determine the influence on drying kinetics of the ultrasonic power applied during the AFD of apple. For that purpose, AFD experiments (-10ºC, 2 m/s and 15% relative humidity) of apple slabs (cv. Granny Smith, 30 x 30 x 10 mm) were carried out with ultrasound application (21 kHz) at different power levels (0, 10.3, 20.5 and 30.8 kW/m3). The drying kinetics was obtained from the initial moisture content and the weight evolution of samples during drying. Experimental results showed a significant (p<0.05) influence of the ultrasound application on drying. Thus, drying time was shorter as higher the ultrasonic power applied. From modeling, it was observed that the effective diffusion coefficient identified was 4.8 times higher when ultrasound was applied at the lowest power tested (10.3 kW/m3) that illustrated the high intensification potential of ultrasound application in the AFD.

[EN] Hot air drying is an energy intensive process and can affect bioactive components. A common method of food drying is in a fixed bed. The application of high-intensity ultrasound could constitute a way of improving traditional convective drying systems. Therefore, the main aim of this work was to assess the influence of high-intensity ultrasound on transfer phenomena during the convective drying in a high-void bed of non-porous materials, like thyme leaves. For this purpose, drying kinetics of thyme leaves were carried out at 1, 2 and 3 m s(-1) air velocity at different air temperatures (40, 50, 60, 70, and 80 +/- 1.2 degrees C), and different levels of acoustic power density (0, 6.2, 12.3, 18.5 kW m(-3)). To address the effect of US on the drying kinetics, a mathematical model was developed considering time varying boundary conditions for heat and mass transfer between the air and the product. Due to the physical characteristic of the material, the influence of the ultrasound power density applied on the internal resistance to the mass transfer was significantly lower than its influence of the external resistance; therefore process intensification is mainly linked to external resistance. Nevertheless, the influence of the application of ultrasound on transport phenomena was only observed at air temperatures and air velocities below 70 degrees C and 3 m s(-1) respectively. (C) 2013 Elsevier Ltd. All rights reserved.

[EN] Thyme leaves are an important source of essential oils with antioxidant activity; these compounds are located in trichomes on the leaf surface. The drying conditions affect not only the drying time but also the antioxidant activity. In the literature, a drying temperature of 70 ºC appears to be the best for drying thyme leaves according to their antioxidant capacity. Considering drying periods at different temperature also could be quality beneficial. From these considerations, the goal of this work was to establish a drying strategy with which to manage a drying temperature on the leaf surface which will enable the drying time to be shortened and improve the antioxidant capacity (AC) of the extract of dried thyme leaves. The drying strategy consisted of two consecutive drying periods in order to manage the drying temperature on the leaf surface. The first drying period was carried out at 80°C (Ta1) until the sample surface reached a temperature of 70 ºC, which then immediately being set to 70, 60, 50 and 40 °C (second drying period (Ta2)), at a different air velocity (v) (1 and 2 m s-1). Compared with constant drying conditions, two consecutive drying periods were found to improve the drying kinetics, the AC increased from 10.5% to 27.4 % while reducing the drying time by 14.5% to 39.2 %. The use of this drying strategy was found to be an interesting means of intensifying the convective drying of thyme leaves and its application should be considered when drying similar materials with bioactive compounds on the surface.

[EN] During storage, the packaging material was crucial in the product s moisture variation. The aim of this work was to study the changes of both the moisture content and the texture of dried apricots packaged in two types of containers, namely glass and polypropylene trays, which were thermosealed with two different films and stored at a constant temperature (5, 15, 25 and 35C). The moisture content and texture of the product were analyzed periodically over a period of 12 months. In addition, a differential scanning calorimetry of the product was carried out for a better understanding of the relationship between these parameters. In samples packaged in films, the maximum force value increased along with storage temperature, while the moisture content decreased. In glass, the values of these parameters remained almost constant. A change in the structure of the material was detected between 25 and 35C

The objective of this work was to determine the influence of temperature, air velocity, and ultrasound application on the drying kinetics of grape seeds. The drying kinetics were determined at 1.0, 1.5, 2.0, and 3.0 m/s and at 40, 50, 60, and 70 C. At 1.0 and 1.5 m/s, the experiments were carried out with and without ultrasound application. To establish the influence of the variables on the drying kinetics, the results were modeled by means of both the Peleg and a diffusion model. The activation energy was determined (Arrhenius equation). For an air velocity of over 1.5 m/s, it was determined that the external resistance to mass transfer was negligible. No influence of ultrasound application was observed, probably due to the fact that grape seeds are very hard and have a low level of porosity.

[EN] Low-temperature air drying represents an alternative means to hot air drying of better retaining the sensory, nutritional and functional properties of foods. However, reducing the air temperature to figures below the product s freezing point involves low drying rates, which largely places constraints on any further industrial application. The main aim of this work was to evaluate the feasibility of using power ultrasound to improve the low-temperature drying of apple, considering not only the kinetic effects but also the influence on the antioxidant potential of the dried apple. For that purpose, apple (Malus domestica cv. Granny Smith) cubes (8.8 mm side) were dried (2 m/s and a relative humidity of under 10%) at low temperatures ( 10, 5, 0, 5 and 10 C) with (20.5 kW/m3) and without ultrasound application. The drying kinetics were modeled by considering the diffusion theory, negligible shrinkage and cubic geometry. In the dried apple, total phenolic and flavonoid contents and antioxidant capacity were measured. The application of power ultrasound sped up the drying kinetics at every temperature tested, achieving drying time reductions of up to 77%, which was linked to the improvement in diffusion and convective mass transport. In overall terms, ultrasound application involved a greater degradation of polyphenol and flavonoid contents and a reduction of the antioxidant capacity, which was related to the cell disruption caused by the mechanical stress of acoustic waves.

[EN] The objective of the study was to analyze the influence of high power ultrasound (HPU) on the supercritical carbon dioxide (SC-CO2) inactivation kinetics of Saccharomyces cerevisiae and to determine the effect of the temperature (31-41 degrees C), pressure (100-350 bar) and composition of the medium (YPD Broth, apple and orange juice) on the process of inactivation. Using a batch-mode SC-CO2 at 350 bar and 36 degrees C, a reduction of 6.7 log-cycles was obtained after 140 min of treatment. However, when HPU (40 W +/- 5 W and 30 kHz) was applied during the SC-CO2 treatments, a reduction of 7 log-cycles was achieved after 2 mm of treatment for all pressures and temperatures applied. The effect of increasing pressure (from 100 to 350 bar, 36 degrees C) or temperature (from 31 to 41 degrees C, 225 bar) did not significantly influence this inactivation level. The application of ultrasound leads to a vigorous agitation and cavitation which could accelerate the SC-CO2 dissolving in the medium. This accelerates the penetration of CO2 into cells and its inactivation mechanisms. In batch operations the application of HPU increases the speed of reaching saturation solubility of CO2 in many liquid media and significantly reduces microbial inactivation times. (C) 2013 Elsevier Ltd. All rights reserved.

[EN] Food properties change during processing, altering the quality of the final product. Sometimes, the important causal relationships are not well known and thus process management is difficult. This is especially true when chemical changes can occur as in the case of the drying of bioactive materials. The aim of this work was to develop a management tool for the thyme drying process, assisted by power ultrasound, to allow the appropriate values of the operating conditions that maximize the antioxidant capacity (AC) of the dried thyme extracts to be determined. For this proposal, the thyme drying process was analyzed at different drying air temperatures (7) (40-80 degrees C), drying air velocities (v(a)) (1-3 m/s) and levels of power ultrasound (US) (0, 6.2, 12.3, 18.5 kW m(-3)). The essential oil was extracted by means of a supercritical fluid extraction method, and its AC was measured by FRAP. The drying velocity and the AC of the dried thyme extracts were both influenced by the magnitude of the air velocity and temperature, and also by power ultrasound. Artificial neural networks were developed to formulate and solve the optimization problem. The developed management tool allowed the optimal conditions of the process to be established, thereby maximizing the AC values in function of the raw materials, process characteristics and room air conditions. (C) 2013 Elsevier Ltd. All rights reserved.

[EN] The aim of this work was to evaluate the effect of high intensity ultrasound and NaCl concentration on the brining kinetics (5 ± 1 C) of pork loin as well as its influence on the textural and microstructural changes. In order to identify the effect of both factors on NaCl and moisture transport, kinetics were analyzed by taking the diffusion theory into account. The textural and microstructural analysis of raw and brined meat both with and without ultrasound application was carried out. The experimental results showed that the brine NaCl concentration not only determined the final NaCl content in meat samples but also the direction of water transport. The NaCl and moisture effective diffusivities were improved by ultrasound application. The final NaCl and moisture content and the ultrasound application promoted changes in instrumentally measured meat texture, which were confirmed via microstructural observations.