Effect of curing conditions and harvesting stage of maturity on Ethiopian onion bulb drying properties

The study was conducted to investigate the impact of curing conditions and harvesting stageson the drying quality of onion bulbs. The onion bulbs (Bombay Red cultivar) were harvested at three harvesting stages (early, optimum, and late maturity) and cured at three different temperatures (30, 40 and 50 oC) and relative humidity (30, 50 and 70%). The results revealed that curing temperature, RH, and maturity stage had significant effects on all measuredattributesexcept total soluble solids

Application of Novel Thermal Technology in Foods Processing

Advanced and novel thermal technologies, such as ohmic heating, dielectric heating (e.g., microwave heating and radio frequency heating), and inductive heating, have been developed to improve the effectiveness of heat processing whilst guaranteeing food safety and eliminating undesirable impacts on the organoleptic and nutritional properties of foods. Novel thermal technologies rely on heat generation directly inside foods, which has implications for improving the overall energy efficiency of the heating process itself. The use of novel thermal technologies is dependent on the complexity and inherent properties of the food materials of interest (e.g., thermal conductivity, electrical resistance, water content, pH, rheological properties, food porosity, and presence of particulates). Moreover, there is a need to address the combined use of thermal processing with emerging technologies such as pulsed electric fields, high hydrostatic pressure, and ultrasound to complement the conventional thermal processing of fluid or solid foods. This Special Issue provides readers with an overview of the latest applications of various novel technologies in food processing. A total of eight cutting-edge original research papers and one comprehensive review paper discussing novel processing technologies from the perspectives of food safety, sustainability, process engineering, (bio)chemical changes, health, nutrition, sensory issues, and consumers are covered in this Special Issue

Root, Tuber and Banana Food System Innovations

This open access book describes recent innovations in food systems based on root, tuber and banana crops in developing countries. These innovations respond to many of the challenges facing these vital crops, linked to their vegetative seed and bulky and perishable produce. The innovations create value, food, jobs and new sources of income while improving the wellbeing and quality of life of their users. Women are often key players in the production, processing and marketing of roots, tubers and bananas, so successful innovation needs to consider gender. These crops and their value chains have long been neglected by research and development, hence this book contributes to filling in the gap. The book features many outcomes of the CGIAR Research Program in Roots, Tubers and Banana (RTB), which operated from 2012-21, encompassing many tropical countries, academic and industry partners, multiple crops, and major initiatives. It describes the successful innovation model developed by RTB that brings together diverse partners and organizations, to create value for the end users and to generate positive economic and social outcomes. RTB has accelerated the scaling of innovations to reach many end users cost effectively. Though most of the book’s examples and insights are from Africa, they can be applied worldwide. The book will be useful for decision makers designing policies to scale up agricultural solutions, for researchers and extension specialists seeking practical ideas, and for scholars of innovation

Root, Tuber and Banana Food System Innovations

This open access book describes recent innovations in food systems based on root, tuber and banana crops in developing countries. These innovations respond to many of the challenges facing these vital crops, linked to their vegetative seed and bulky and perishable produce. The innovations create value, food, jobs and new sources of income while improving the wellbeing and quality of life of their users. Women are often key players in the production, processing and marketing of roots, tubers and bananas, so successful innovation needs to consider gender. These crops and their value chains have long been neglected by research and development, hence this book contributes to filling in the gap. The book features many outcomes of the CGIAR Research Program in Roots, Tubers and Banana (RTB), which operated from 2012-21, encompassing many tropical countries, academic and industry partners, multiple crops, and major initiatives. It describes the successful innovation model developed by RTB that brings together diverse partners and organizations, to create value for the end users and to generate positive economic and social outcomes. RTB has accelerated the scaling of innovations to reach many end users cost effectively. Though most of the book’s examples and insights are from Africa, they can be applied worldwide. The book will be useful for decision makers designing policies to scale up agricultural solutions, for researchers and extension specialists seeking practical ideas, and for scholars of innovation

Design and Development of a Multi-Frequency System for Microwave Heating

[ES] La utilización de sistemas de microondas para aplicaciones de calentamiento está muy extendida, principalmente por su uso en el calentamiento doméstico. El volumen de ventas del horno de microondas doméstico refleja un dato curioso: es el electrodoméstico más vendido en el mundo cada año. Por ello, el coste de producción del elemento principal, el magnetrón, presenta unos márgenes de beneficio imbatibles. Sin embargo, los avances en la fabricación de generadores de RF de alta potencia de estado sólido han puesto de manifiesto no solo las limitaciones de los sistemas basados en magnetrón sino también las grandes ventajas de la tecnología de transistores. Actualmente, los amplificadores de potencia de estado sólido han alcanzado una madurez suficiente como para competir en eficiencia, coste y calidad de la onda generada con el magnetrón. Las principales ventajas de los transistores son un reducido tamaño, tensiones de alimentación bajas, un espectro puro en frecuencia, un mayor tiempo de vida y el control digital directo. Los sistemas de microondas con esta tecnología están siendo introducidos en el mercado desde hace diez años, aunque las aplicaciones reales que los utilizan son escasas. La principal razón es la falta de diseños de aplicadores específicos para sacar el máximo provecho a las fuentes de estado sólido. , por tanto, es éste el objetivo de la tesis doctoral. Los sistemas S2MH (Solid-State Microwave Heating) se presentan en esta disertación doctoral como una alternativa que ofrece un calentamiento mejorado. La posibilidad de seleccionar la frecuencia exacta, ajustar la potencia de salida y realizar barridos de fase de forma coherente con múltiples iluminadores proporcionan al sistema un control preciso del proceso de calentamiento. El resultado directo de éste es un calentamiento homogéneo y el uso de la tecnología de microondas en procesos de alto valor añadido y fuerte dependencia con la temperatura. Esta tesis doctoral presenta el trabajo realizado en el diseño y fabricación de dos sistemas S2MH: el primero es un horno estático versátil para diferentes procesos químicos, y el segundo un horno de transporte para el secado de almendras. Estos dos sistemas están formados por el SSMGS (Solid-State Microwave Generator System), que incluye cuatro amplificadores de estado sólido (SSPA) con una generación de la onda coherente, y el aplicador. Para el diseño del SSMGS se han tenido en cuenta los requisitos de potencia y frecuencia de cada aplicación. Se ha utilizado un SSMGS con cuatro PA de 250 W a 2,450 MHz para el horno de aplicaciones químicas, mientras que el secado de almendras necesita cuatro PA de 500 W a 915 MHz. Los dos sistemas de generación de microondas permiten un control individual o combinado de los parámetros de los cuatro módulos amplificadores, i.e., potencia, frecuencia y fase. Todo el proceso de diseño ha sido llevado a cabo mediante modelado multi-físico, poniendo un especial cuidado en las propiedades termofísicas y dieléctricas de los alimentos y soluciones acuosas que tienen una importante dependencia con la temperatura. El comportamiento completo del sistema aplicador se ha estudiado con estas herramientas. Tras la fabricación de los dos prototipos o pruebas de concepto (PoC), los resultados obtenidos presentan un comportamiento similar al modelo y muestran, además, prometedoras mejoras frente a los sistemas actuales. El sistema de aplicaciones químicas presenta mejoras en la distribución de campo, independientemente de la aplicación y la carga. Y el sistema de secado de almendras proporciona un mayor control sobre el proceso evitando la pérdida de material por sobrecalentamiento.[CA] La utilització de sistemes de microones en aplicacions d'escalfament està molt estesa, principalment pel seu us en escalfament domèstic. El volum de ventes del forn de microones domèstic reflexa una informació curiosa: es l'electrodomèstic més venut anualment al món. Per això, el cost de producció del seu element principal, el magnetró, presenta uns marges de benefici imbatibles. No obstant això, els avanços en la fabricació de generadors de RF d'alta potencia d'estat sòlid han posat de manifest tant les limitacions dels sistemes basats en magnetró, com els grans avantatges de la tecnologia de transistors. Actualment, els amplificadors de potència d'estat sòlid son el suficientment madurs com per competir en eficiència, cost i qualitat de l'ona generada amb el magnetró. Els principals avantatges dels transistors son les dimensions reduïdes, tensions d'alimentació baixes, un espectre pur en freqüència, major temps de vida i el control digital directe. Els sistemes de microones amb aquesta tecnologia estan sent introduïts al mercat des de fa deu anys, malgrat les aplicacions reals son escasses. El principal motiu és la falta de dissenys de aplicadors específics per obtindré el màxim profit de les fonts d'estat sòlid. , por tanto, es éste el objetivo de la tesis doctoral. Els sistemes S2MH es presenten en esta dissertació doctoral com una alternativa que ofereix un escalfament millorat. La possibilitat de seleccionar la freqüència exacta, ajustar la potència d'eixida i realitzar un rastreig de fase de forma coherent amb molts il·luminadors proporcionen al sistema un control precís del procés d'escalfament. El resultat directe d'aquest es un escalfament homogeni i el us de la tecnologia de microones en processos d'alt valor afegit i alta sensibilitat a la temperatura. Aquesta dissertació doctoral presenta el treball realitzat en el disseny i fabricació de dos sistemes S2MH: el primer és un forn estàtic i versàtil per a diferent processos químics, i el segon es tracta d'un forn de transport per l'assecatge d'ametles. Tots dos sistemes estan formats pel SSMGS, que inclou quatre amplificadors d'estat sòlid (SSPA) amb generació coherent de l'ona, i l'aplicador. Per al disseny del SSMGS s'han tingut en compte els requisits de potència i freqüència de cada aplicació. S'ha utilitzat un SSMGS amb quatre PA de 250 W a 2,450 MHz per al forn d'aplicacions químiques, mentre que per al d'assecat d'ametla es necessita quatre PA de 500 W a 915 MHz. Ambdós sistemes de generació de microones permeten un control individual o combinat dels paràmetres dels quatre mòduls amplificadors, i.e., potència, freqüència i fase. Tot el procés de disseny ha sigut realitzat amb l'ajuda del modelat multi-físic, prestant una especial atenció a les propietats termofísiques i dielèctriques dels aliments i solucions aquoses, que tenen una important dependència de la temperatura. El comportament complet del sistema aplicador ha sigut estudiat amb estes ferramentes digitals. Després de la fabricació dels dos prototips o proves de concepte (PoC), els resultats obtinguts presenten un comportament similar al model i, a més a més, mostren millores prometedores front als sistemes actuals. El sistema d'aplicacions químiques presenta millores en la distribució de camp, independentment de l'aplicació i la càrrega. I el sistema d'assecatge d'ametlles proporciona un major control sobre el procés, evitant la pèrdua de material per sobreescalfament.[EN] Microwave systems are widely used for heating applications, mainly domestic food heating. The microwave oven sales figures place it as the first domestic appliance, giving its core element, the magnetron, an unbeatable production cost margin. However, recent improvements in RF high-power generator manufacturing have pointed out not only the limitations of these systems based on the magnetron but also the main benefits of the transistors technology. Nowadays, solid-state power amplifiers are mature enough to compete in efficiency, cost and quality with the magnetron. Transistors' main benefits are their reduced size, low operation voltages, pure frequency spectrum, lifetime, and straightforward digital control. Microwave systems based on solid-state power amplifiers have been recently introduced, although the real applications making use of them are rare. The main issue is the lack of applicator designs for specific solid-state sources that fully exploit the mentioned advantages; therefore, this is the main objective of the present PhD thesis. Solid-State Microwave Heating (S2MH) systems are presented in this PhD dissertation as an alternative that offers enhanced heating. Fine frequency selection, adjustable output power and coherent phase sweep in multiple outputs provide the system with accurate control over the heating process. The direct outcome of this control is the production of homogeneous heating and the application of microwave technology into high-added-value temperature-sensitive processes. The complete design and manufacture of two S2MH systems have been carried out and presented in this PhD thesis. The two designed systems are a multi-process chemical lab batch oven and an almond drying conveyorized oven. These two systems are composed of the Solid-State Microwave Generator System (SSMGS), consisting of four Solid-State Power Amplifiers (SSPA) with coherent wave generation, and the applicator. The design of the SSMGS has been carried out according to the power and frequency requirements of the application. A 4 x 250 W SSPA at 2,450 MHz SSMGS has been used for the chemical processes oven, while the almond drying application needs 4 x 500 W SSPA at 915 MHz. Both SSMGS allow the individual or combined digital control of the parameters of the four amplifying modules, i.e., power, frequency and phase. Multiphysics modelling has been thoroughly studied with special attention to the temperature-dependent thermophysical and dielectric properties of food and liquid solutions. The overall applicators' behaviour has been analysed with this tool. After completing the two PoC (Proof of Concept), the results show good agreement with the models. Both PoCs have shown promising improvements to the current state-of-the-art systems. The chemical applications PoC shows electromagnetic field distribution improvements, independent of the application or load. On the other hand, the almonds drying system provides increased control over the process avoiding material losses through overheating.Santón Pons, P. (2022). Design and Development of a Multi-Frequency System for Microwave Heating [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/19132

OCM 2013 - Optical Characterization of Materials - conference proceedings

The state of the art in optical characterization of materials is advancing rapidly. New insights into the theoretical foundations of this research field have been gained and exciting practical developments have taken place, both driven by novel applications that are constantly emerging. This book presents latest research results in the domain of Characterization of Materials by spectral characteristics of UV (240 nm) to IR (14 µm), multispectral image analysis, X-Ray, polarimetry and microscopy

OCM 2013 - 1st International Conference on Optical Characterization of Materials: March 6th - 7th, 2013, Karlsruhe, Germany

The state of the art in optical characterization of materials is advancing rapidly. New insights into the theoretical foundations of this research field have been gained and exciting practical developments have taken place, both driven by novel applications that are constantly emerging. This book presents latest research results in the domain of Characterization of Materials by spectral characteristics of UV (240 nm) to IR (14 µm), multispectral image analysis, X-Ray, polarimetry and microscopy

Combining lasers with emerging technologies for minimal processing

Conservative estimates place the economic cost of food poisoning at hundreds of millions of pounds per annum. Recent market expansion of minimally processed fresh fruit and vegetables has resulted from the consumer's desire of convenience foods that have been peeled, cut, shredded or even washed. These produce, however, are likely to be contaminated. Such produce has a natural high microbiological burden. Minimally processing the food results in surface damage that is likely to favour bacterial adhesion. The cutting process leads to cellular damage, which coupled with increased adhesion and leakage of intracellular material, can lead to increased growth rate of spoilage organisms or pathogens. Minimally processed fruit and vegetables are often washed in water or water containing chemicals. The wash water can help distribute bacteria into the damaged sites on the processed fruit or vegetables. The use of chlorine has been associated with the production of carcinogenic and mutagenic substances and consequently there are fears over its use and potential accumulation within the body. Many government policies are encouraging people to eat more fresh fruit and vegetables. It is important therefore, that processors use the best practice available to supply fruit and vegetables with the minimum risk to consumers through digestion of pathogens and with a long a shelf life as possible to aid distribution channels, minimise waste and increase profits for processors. This research was seeking to identify novel ways to reduce the levels of contamination on carrots and potatoes and extend their shelf-life. Technology was developed to exploit different parts of the electromagnetic spectrum to kill bacteria. The systems included a CO2 laser, conventional UV lamps, and microwave irradiation. As an adjunct to these processes, H2O2 treatments and combination treatments were used. These systems were combined to kill bacteria on different substrates, fruit and vegetables. Comparison of shelf life tests and optimum treatment processes were also done. On carrots and potatoes the investigation of vitamin A and C levels, respectively, also indicated that their nutritious quality had not been degraded with any of the treatments. Using ozone as a bactericide and bioluminescence as a measurement of viability or metabolic activity, a real time monitoring system was developed to measure surface decontamination. The Escherichia coli strain DH5alpha PT7-3 with its plasmid encoded with ampicillin resistance contained the lux ABCDE genes from Xenorhadus luminescence, were used as the reference organism. Results showed that the bioluminescence responded instantaneously to treatment. Bioluminescence measurements were recorded in decibel, after 15 min of ozone treatment the bioluminescence was reduced by 4 dB and E. coli (lux) were inactivated. To investigate the response of various Gram-positive and Gram-negative organisms to ozone treatment, Campylobacter jejuni, Bacillus cereus, Escherichia coli, Listeria monocytogenes, Salmonella typhimurium and Staphylococcus aureus were inoculated on plates and treated with ozone. The treatment achieved about 2 - 2.5 D-value reduction on plates. The same treatment was less effective when the experiments were repeated on contaminated chicken and salmon samples. A log reduction range between 0.37 - 1.5 was achieved