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Tesis por compendio, [ES] La industria alimentaria ha mostrado un enorme interés por desarrollar nuevos productos a base de fruta con el fin de satisfacer la demanda saludable y sostenible de productos alimentarios de los consumidores. En este sentido, un puré de naranja liofilizado podría representar una opción viable. La liofilización del puré da lugar a una torta que puede consumirse directamente como snack, o puede triturarse para obtener un polvo que puede utilizarse para una amplia gama de aplicaciones. Una optimización adecuada de las condiciones de liofilización podría ayudar a reducir su duración sin afectar a las características del producto final. Sin embargo, los alimentos deshidratados pueden presentar problemas de colapso estructural relacionados con su baja temperatura de transición vítrea. En este sentido, una técnica frecuente para la estabilización de estos productos deshidratados es la incorporación de biopolímeros de alto peso molecular. El objetivo de esta Tesis ha sido el diseño del proceso de liofilización para la obtención de un snack de naranja. Para ello se ha estudiado la influencia de diferentes combinaciones de biopolímeros en la estabilidad física del puré de naranja liofilizado (snack de naranja) y en la bioaccesibilidad in vitro de sus compuestos bioactivos. Asimismo, se ha evaluado su efecto en las propiedades de flujo en aire y de rehidratación del polvo de naranja. Se ha trabajado con diferentes combinaciones de goma Arábiga, maltodextrina, almidón sustituido por grupos octenil succínico, almidón nativo de maíz, fibras de guisante y de bambú. Los resultados mostraron la necesidad de incorporar estos biopolímeros para aumentar la actividad de agua crítica y el contenido de agua crítico para la transición vítrea, el cual se ha relacionado con la pérdida de la textura del snack. Si bien ninguna de las mezclas de biopolímeros fue mejor que las otras en higroscopicidad, carácter anti-plastificante, color y propiedades mecánicas del snack, la mezcla GA con F, [CA] La indústria alimentària ha mostrat un enorme interés per desenvolupar nous productes a base de fruita amb la finalitat de satisfer la demanda saludable i sostenible de productes alimentaris dels consumidors. En aquest sentit, un puré de taronja liofilitzat podria representar una opció viable. La liofilització del puré dona lloc a una coca que pot consumir-se directament com a snack, o pot triturar-se per a obtindre una pols que pot utilitzar-se per a una àmplia gamma d'aplicacions. Una optimització adequada de les condicions de liofilització podria ajudar a reduir la seua duració sense afectar les característiques del producte final. No obstant això, els aliments deshidratats poden presentar problemes de col·lapse estructural relacionats amb la seua baixa temperatura de transició vítria. En aquest sentit, una tècnica freqüent per a l'estabilització d'aquests productes deshidratats és la incorporació de biopolímers d'alt pes molecular. L'objectiu d'aquesta Tesi ha sigut el disseny del procés de liofilització per a l'obtenció d'un snack de taronja. Per a això s'ha estudiat la influència de diferents combinacions de biopolímers en l'estabilitat física del puré de taronja liofilitzat (snack de taronja) i en la bioaccessibilitat in vitro dels seus compostos bioactius. Així mateix, s'ha avaluat el seu efecte en les propietats de flux en aire i de rehidratació de la pols de taronja. S'ha treballat amb diferents combinacions de goma Aràbiga, maltodextrina, midó substituït per grups octenil succínic, midó natiu de dacsa, fibres de pésol i de bambú. Els resultats van mostrar la necessitat d'incorporar aquests biopolímers per a augmentar l'activitat d'aigua crítica i el contingut d'aigua crític per a la transició vítria, el qual s'ha relacionat amb la pèrdua de la textura del snack. Si bé cap de les mescles de biopolímers va ser millor que les altres en higroscopicitat, caràcter anti-plastificant, color i propietats mecàniques del snack, la mescla GA amb FB va ser la que, [EN] Food industries have showed a huge interest in developing new fruit-based products to satisfy the healthy and sustainable demand of food products by consumers. In this sense, offering a freeze-dried orange puree could represent a feasible option. Freeze-drying the puree results in a cake that can be consumed directly as a snack, or it can be crushed to obtain a powder that can be used for a wide range of applications. A suitable optimisation of the freeze-drying conditions could help to reduce its duration without affecting the characteristics of the final product. However, dehydrated foods may present problems of structural collapse related to its low glass transition temperature. In this sense, an approach for the stabilisation of dehydrated products is the incorporation of high molecular weight biopolymers. The aim of this Thesis has been the design of the freeze-drying process to obtain an orange snack. The influence of different combinations of biopolymers on the physical stability of the freeze-dried orange puree (orange snack) and on the in vitro bioaccessibility of its bioactive compounds has been studied. Their effect on the air flow and rehydration properties of an orange powder obtained after crushing the snack has also been evaluated. Different combinations of gum Arabic, maltodextrin, starch substituted with octenyl succinic groups, native corn starch, pea and bamboo fibres were used. The results showed the need to incorporate these biopolymers to increase the critical water activity and the critical water content for the glass transition, which has been related to the loss of snack texture. Although none of the biopolymer combinations was better than the others in terms of hygroscopicity, anti-plasticising character, colour, and mechanical properties of the snack, the GA mixed with FB was the one that improved the bioaccessibility of vitamin C (VC) and total phenolic compounds (TP). This same combination offered the shortest wetting times and a lo

[ES] Existen muchos estudios que relacionan el consumo regular de frutas con importantes beneficios para la salud. Esto es debido a la gran cantidad de fibra, vitaminas y otros compuestos bioactivos presentes en ellas, los cuales pueden ser de gran ayuda en la prevención de algunas enfermedades. En los últimos años, el consumidor se ha decantado por consumir productos con alto valor nutricional y, como consecuencia del estilo de vida actual, existe una alta demanda de productos con fácil manejo para su consumo. Algunos de los principales inconvenientes de las frutas son su estacionalidad y corta vida útil, por lo que resulta interesante ofrecer productos de fruta de alto valor nutritivo y sensorial, estables y fácil manejo. La liofilización es una técnica que permiten obtener productos altamente estables microbiológicamente, debido a su bajo contenido de humedad, y con una máxima calidad sensorial, nutritiva y funcional. Sin embargo, se trata de un proceso largo y energéticamente costoso. Con base a lo anterior, el objetivo de esta tesis ha sido seleccionar las mejores condiciones de liofilización para la obtención de dos productos de naranja, uno la propia torta liofilizada y otro el polvo obtenido por trituración de la misma. Así, la sección uno se centra en evaluar la influencia tanto del contenido de agua como de la composición en solutos de un producto naranja en algunas propiedades de la torta liofilizada y del polvo correspondiente. Las propiedades analizadas se seleccionaron teniendo en cuenta tanto la retención de los compuestos bioactivos, como la porosidad, el color y las propiedades mecánicas de la torta obtenida y del polvo conseguido tras su trituración, además de las propiedades de flujo del polvo y su comportamiento frente a la rehidratación. En base a los resultados obtenidos se ha podido concluir que el puré de naranja es más recomendable a los efectos de obtener un producto tipo snack crujiente y el zumo cuando se desee un polvo para rehidratar, e, [CA] Existeixen molts estudis que relacionen el consum regular de fruites amb importants beneficis per a la salut. Això és degut a la gran quantitat de fibra, vitamines i altres compostos *bioactivos que es troben elles, els quals poden ser de gran ajuda en la prevenció d'algunes malalties. En els últims anys el consumidor s'ha decantat per consumir productes amb alt valor nutricional i, a conseqüència de l'estil de vida actual, existeix una alta demanda de productes amb fàcil maneig per al seu consum. Alguns dels principals inconvenients de les fruites són la seua estacionalitat i curta vida útil, per la qual cosa resulta interessant oferir productes de fruita d'alt valor nutritiu i sensorial, estables i fàcil maneig. La liofilització és una tècnica que permeten obtindre productes altament estables microbiologicament, a causa del seu baix contingut d'humitat, i amb una màxima qualitat sensorial, nutritiva i funcional. No obstant això, es tracta d'un procés llarg i energèticament costós. Amb base a l'anterior, l'objectiu d'aquesta Tesi ha sigut seleccionar les millors condicions de liofilització per a l'obtenció de dos productes de taronja, un la pròpia coca liofilitzada i un altre la pols obtinguda per trituració d'aquesta. Així, la primera part de la Tesi se centra en avaluar la influència tant del contingut d'aigua com de la composició en soluts d'un producte taronja en algunes propietats de la coca liofilitzada i de la pols corresponent. Les propietats a analitzar es van seleccionar tenint en compte tant la retenció dels compostos bioactius, com la porositat, el color i les propietats mecàniques de la coca obtinguda i de la pols aconseguida després de la seua trituració, a més de les propietats de flux de la pols i el seu comportament enfront de la rehidratació. Sobre la base dels resultats obtinguts s'ha pogut concloure que el puré de taronja és més recomanable a l'efecte d'obtindre un producte tipus snack cruixent i el suc quan es desitge una pols per a rehidr, [EN] There are many studies linking regular fruit consumption with important health benefits. This is due to the large amount of fibre, vitamins and other bioactive compounds found in them, which can be of great help in the prevention of some diseases. In recent years, consumers have become more inclined to consume products with high nutritional value and, as a consequence of today's lifestyle, there is a high demand for products that are easy to handle for consumption. Some of the main disadvantages of fruits are their seasonality and short shelf life, so it is interesting to offer fruit products of high nutritional and sensory value that are stable and easy to handle. Freeze-drying is a technique that makes it possible to obtain highly microbiologically stable products, due to their low moisture content, and with maximum sensory, nutritional and functional quality. However, it is a long and energy-intensive process. Based on the above, the aim of this Doctoral Thesis has been to select the best freeze-drying conditions for obtaining two orange products, one the freeze-dried cake itself and the other the powder obtained by crushing it. Thus, the first part of the Thesis focuses on evaluating the influence of both the water content and the solute composition of an orange product on some properties of the freeze-dried cake and the corresponding powder. The properties to be analysed were selected taking into account the retention of the bioactive compounds, the porosity, the colour and the mechanical properties of the cake obtained and of the powder obtained after grinding, as well as the flow properties of the powder and its behaviour against rehydration. Based on the results obtained, it can be concluded that orange puree is more recommendable for obtaining a crunchy snack-type product and juice when a powder for rehydration is desired, in this case avoiding any heat treatment before freeze-drying. In the second part of the Thesis, the impact of the drying temperatu

[ES] En la elaboración de productos por la industria alimentaria, desde la recepción de las materias primas hasta su consumo, se generan grandes cantidades de residuos que tienen un alto impacto negativo en la sostenibilidad del planeta. En el caso de la industria de la transformación de frutas, la gestión adecuada y la conversión del residuo en un recurso, intentando llegar a la generación “cero de residuos”, no sólo aportaría un respiro al planeta, sino que podría aportar también nuevos ingredientes para la alimentación humana. Por otra parte, los ingredientes naturales en la industria alimentaria, cosmética y farmacéutica están aumentando en los últimos años y son cada vez más demandados por los consumidores, para cumplir con la normativa actual europea que apuesta por los compuestos naturales en lugar de los sintéticos. En este sentido, el residuo obtenido después de la extracción del zumo de naranja, una vez deshidratado, por sus problemas de degradación debido a su alto contenido en agua, y convertido en polvo, podría transformarse en un producto comercial con función tecnológica interesante. Por su composición podría tener potencial como ingrediente funcional en relación con los aspectos organolépticos, microestructurales y mecánicos/físicos. Así, podría mejorar la estabilidad y la textura de emulsiones, inhibir la sinéresis o actuar como agente gelificante y/o espesante, por ejemplo. Este trabajo se centra en la caracterización tecnofuncional del residuo derivado de la extracción del zumo de naranja, liofilizado y en polvo. Además, y teniendo en cuenta que los alimentos deshidratados y con alto contenido en azúcares necesitan de la incorporación de biopolímeros de alto peso molecular para su estabilización física, se ha estudiado la influencia de goma arábiga en las propiedades analizadas. Los resultados obtenidos indican que la presencia de goma mejora la flotabilidad, disminuye la higroscopicidad y favorece la instantaneidad en agua del coproducto del zumo, [EN] In the elaboration of products by the food industry, from the reception of raw materials to their consumption, large quantities of waste are generated that have a high negative impact on the sustainability of the planet. In the case of the fruit processing industry, the proper management and conversion of waste into a resource, trying to reach "zero waste" generation, would not only bring a respite to the planet, but could also provide new ingredients for human nutrition. On the other hand, natural ingredients in the food, cosmetics and pharmaceutical industries have been increasing in recent years and are increasingly in demand by consumers, in order to comply with current European regulations that favour natural compounds over synthetic ones. In this sense, the residue obtained after the extraction of orange juice, once dehydrated, due to its degradation problems due to its high water content, and converted into powder, could be transformed into a commercial product with an interesting technological function. Due to its composition, it could have potential as a functional ingredient in relation to organoleptic, microstructural and mechanical/physical aspects. Thus, it could improve the stability and texture of emulsions, inhibit syneresis or act as a gelling and/or thickening agent, for example. This work focuses on the techno-functional characterisation of the freeze-dried and powdered orange juice extraction residue. In addition, and taking into account that dehydrated foods with a high sugar content require the incorporation of high molecular weight biopolymers for their physical stabilisation, the influence of gum arabic on the properties analysed has been studied. The results obtained indicate that the presence of gum improves the buoyancy, decreases the hygroscopicity and favours the water instantaneity of the orange juice powder co-product, although it hinders the interaction with fat.

[ES] Como resultado de las diferentes actividades de la industria agroalimentaria, se genera una gran cantidad de residuos orgánicos que deben ser gestionados de manera adecuada ya que impactan negativamente sobre el medio ambiente. Cada vez más, se busca una revaloración de estos desechos para encontrar los beneficios que pueden aportar a los seres vivos. Con relación a la producción de naranjas, algunas industrias de transformación reutilizan los residuos provenientes de esta fruta obteniendo productos destinados al consumo animal, sin plantear la posibilidad de extraer compuestos bioactivos o utilizarlos de manera que se puedan emplear como ingredientes funcionales en alimentación humana saludable. Para poder encontrar su mejor uso, y con la intención de aplicarlo en forma de polvo por la mayor facilidad de manejo y mayor vida útil, se ha buscado tenerlo, previamente, debidamente caracterizado. La composición de estos coproductos, compuestos principalmente por piel, en el caso de la industria de las conservas, y piel, segmentos y zumo, en el caso de la industria de extracción de zumo, es similar pero no igual y por eso se ha realizado una comparación entre ambos, ya que la diferente composición podría dar lugar a productos en polvo con diferentes propiedades y, por tanto, con distintos usos. En este sentido, en este trabajo se ha realizado un análisis proximal de los coproductos del zumo y del puré de naranja determinando la humedad, azúcares totales, proteínas, cenizas, grasas y fibra dietética total, soluble e insoluble. Además, se ha analizado el contenido en vitamina C, hesperidina y narirutina, viendo también cómo afecta la adición de goma arábiga (GA) y almidón esterificado con ácido octenil succínico (OSA) a su estabilidad. Los resultados han mostrado que ambos coproductos son similares en macrocomponentes pero el proveniente del zumo es más rico en compuestos bioactivos. Los biopolímeros añadidos no parecen ejercer un claro efecto protector sobre estos co, [EN] As a result of the different activities of the agri-food industry, a large amount of organic waste is generated, which must be properly managed as it has a negative impact on the environment. Increasingly, a re-evaluation of this waste is being sought in order to find the benefits it can bring to living beings. In relation to the production of oranges, some processing industries reuse the waste from this fruit to obtain products for animal consumption, without considering the possibility of extracting bioactive compounds or using them as functional ingredients in healthy human food. In order to find the best use for them, and with the intention of applying them in powder form because they are easier to handle and have a longer useful life, we have sought to have them duly characterised beforehand. The composition of these co-products, composed mainly of peel, in the case of the canning industry, and peel, segments and juice, in the case of the juice extraction industry, is similar but not the same, which is why a comparison has been made between the two, as the different composition could give rise to powdered products with different properties and therefore different uses. In this sense, in this work, a proximal analysis of the two co-products has been carried out, determining the moisture, total sugars, proteins, ashes, fats and soluble and insoluble dietary fibre. In addition, the content of vitamin C, hesperidin and narirutin to see how the adiction of gum arabic (GA) and esterified starch with octenyl succinic acid (OSA) affect its stability. The results have shown that both co-products are similar in macrocomponents but the one from the juice is richer in bioactive compounds. The added biopolymers do not appear to exert a clear protective effect on these compounds.

[ES] La citricultura española produce unos 7 millones de toneladas de cítricos al año siendo nuestro país uno de los principales productores a nivel mundial, pero sobre todo es reconocido por ser el principal exportador de cítricos de mesa. De hecho, más del 52% del volumen anual producido se exporta para consumo en fresco. El actual marco normativo establece estrictas normas de comercialización al sector por el cual cada año, se generan entre un 10 y 20% de destríos que no pueden comercializarse para consumo en fresco por presencia de defectos como son calibres inapropiados o defectos de color en la piel. En las últimas décadas, ha surgido una industria de transformación, principalmente de zumos, que procesa estos volúmenes de destríos y que, a su vez, debe de dar salida al momento por el carácter perecedero de la fruta. No obstante, de todo el volumen de cítricos que se recepciona en la industria de transformación, más del 50% es biomasa formada por cortezas y membranas que se destinan al sector de piensos sin obtener apenas valor económico. Este volumen de biomasa es rico en compuestos de gran interés tanto para la industria alimentaria por su riqueza en nutrientes como la fibra dietética, así como para el sector farmacéutico por su riqueza en flavonoides. En base a esto, el objetivo general de esta Tesis Doctoral fue investigar la posible valorización de las corrientes de biomasa generadas en los procesos de fabricación de zumos cítricos. Para ello, el primer paso fue la caracterización de los flavonoides cítricos de mayor interés en las distintas corrientes de biomasa que resultan de la industria de fabricación de zumos, y que son, el propio zumo, las cortezas y las membranas del endocarpio. Los flavonoides seleccionados fueron la hesperidina, narirutina, diosmina, nobiletina, tangeretina y sinensetina y se cuantificaron en 6 variedades de naranja y otras 6 de mandarina. De esta caracterización se concluyó que la flavanona hesperidina era la más abundante, repr, [CA] La citricultura espanyola produeix uns 7 milions de tones de cítrics a l'any, situant al nostre país entre els 5 o 6 principals productors del món, però sobre tot és reconeguda per ser el principal exportador de cítrics mundial. De fet més del 52 % del volum produït anualment és exportant en fresc. L'actual marc normatiu estableix unes estrictes normes de comercialització al sector pel qual cada any es generen entre un 10% i 20% de rebuig que no pot ser comercialitzat en fresc a causa de la presència de defectes com poden ser calibres inadequats o defectes de coloració a la pell. A les últimes dècades, ha sorgit una industria de transformació que processa estos volums de fruita de rebuig i que al mateix temps, se'ls ha de donar eixida immediata. No obstant, de tot el volum de cítrics que es rep a la industria, més del 50% és biomassa formada per les corfes i membranes que generalment s'acaben destinant al sector de pinsos obtenint-ne escàs valor econòmic. Este volum de biomassa és ric en compostos de interès tant per a la industria alimentaria per la seua riquesa en nutrients com la fibra dietètica, així como pel sector farmacèutic per la alta riquesa en flavonoides. En base a això l'objectiu general d'esta tesi doctoral va consistir en la valorització dels distints corrents de biomassa generats als processos de fabricació de sucs cítrics. Per a abordar este objectiu, el primer pas va ser la caracterització dels flavonoides cítrics de interès als distints corrents de biomassa que resulten de la industria de transformació, i que són el propi suc, les corfes i les membranes de l'endocarp. Els flavonoides seleccionats van ser la hesperidina, narirutina, diosmina, nobiletina, tangeretina y sinensetina i es quantificaren en 6 varietats de taronja i 6 de mandarina. D'esta caracterització es va arribar a la conclusió que la hesperidina era la més abundant, representant més del 60% dels flavonoides quantificats a les varietats cítriques estudiades. A més, més d'un 70%, [EN] The Spanish citrus sector produces about 7 million tons of citrus per year. This figure places our country among the main producers worldwide, but the most important fact is that Spain is recognized as the main exporter of citrus for fresh consumption. In fact, more than 52% of the annual volume produced is exported to third countries. The current legal framework establishes strict marketing standards for the fresh fruit sector. Because of this, between 10 and 20% of the total citrus fruits produced do not meet those market standards and are rejected. This kind of fruits cannot be marketed for fresh consumption due to the presence of defects, such as inappropriate sizes or colour defects on the skin. In recent decades, a transformation industry has emerged, that processes these volumes of rejects. However, more than 50% of the entire volume of fruits that are received in the processing sites, is represented by the biomass formed by endocarp membranes and fruit peels that generally ends up being destined for the animal feed at a very residual economical value. This volume of biomass is rich in chemical compounds of great interest both for the food industry, due to its richness in certain nutrients such as dietary fiber, as well as for the pharmaceutical sector, due to its high richness in flavonoids. Based on this, the general objective of this Doctoral Thesis was to investigate the recovery options of certain substances of the different biomass streams generated during the citrus transformation at the fruit juice industry. To accomplish this objective, the first step was the characterization of the citrus flavonoids of greatest interest, in the different biomass streams that result from the manufacture of juices, and that are, the juice itself, the membranes of the endocarp and the peels. The selected flavonoids were hesperidin, narirutin, diosmin, nobiletin, tangeretin and sinensetin and were quantified in 6 varieties of orange and another 6 of mandarin. From

[EN] Nowadays, the consumer is looking for healthier, more attractive, ready-to-eat, and safer foodstuffs than fresh products. Despite freeze drying being known for providing high added value products, it is a slow process which is conducted at low pressures, so, in terms of energy consumption, it turns out to be quite costly for the food industry. With the purpose of obtaining a freeze-dried orange puree, previously formulated with gum Arabic and bamboo fiber, which can be offered to consumers as a snack at a low economic cost, the impact of the process conditions on energy consumption has been considered. The product temperature evolution and the energy consumption were registered during the drying of frozen samples at different combinations of chamber pressures (5 and 100 Pa) and shelf temperatures (30, 40 and 50 & DEG;C). In each case, the time processing was adapted in order to obtain a product with a water content under 5 g water/100 g product. In this study, the secondary drying stage was considered to start when the product reached the shelf temperature and both the pressure and the temperature affected the duration of primary and secondary drying stages. The results obtained led to the conclusion that the shorter duration of the process when working at 50 & DEG;C results in significant energy saving. Working at a lower pressure also contributes to a shortening of the drying time, thus reducing the energy consumption: the lower the temperature, the more marked the effect of the pressure.

[EN] Fruits are essential components of a healthy diet contributing to the prevention of different diseases. Nevertheless, their consumption is limited among the population for reasons of convenience, among others. High-quality products are obtained by freeze-drying; however, dehydrated fruit presents a physical stability problem associated with the glass transition of its amorphous matrix. A common technique to prevent the rubbery state is the incorporation of biopolymers that contribute to increasing the glass transition temperature or that may exert a steric role. Nevertheless, the chemical composition and physical properties of these biopolymers may affect the quality of the dehydrated product which could compromise its use for specific applications. This work studies the impact of gum Arabic, bamboo fibre, maltodextrin, pea fibre, starch substituted with octenyl succinic groups and native corn starch added to an orange puree, on powder flowability and rehydration behaviour of the freeze-dried fruit powder. As regards the flowability, according to the angle of repose values (37-42 degrees), all powder formulations were considered in the range of 'acceptable' powders. However, both samples containing maltodextrin showed significantly the lowest angle of repose value (37-38 degrees), and therefore a better flowability. Samples containing gum Arabic, bamboo fibre and maltodextrin showed the lower wetting time (175-570 s), which is desired for rehydration, compared to those formulated with OSA (914-1887 s). Moreover, sample with gum Arabic showed the lowest viscosity after rehydration (0.199 Pas), desired to be consumed as a juice. According to the obtained results, if to get an orange puree powder with a good flowability is desired, the use of maltodextrin may be recommended. However, if rehydration is preferred, the use of gum Arabic is more recommended.

[EN] Dehydrated fruit puree may be a convenient way to promote the healthy consumption of fruit based foods. Drying carriers, highly used by the food industry to stabilize dried fruit products, may show a potential encapsulating capacity of the biocompounds, that could also limit their bioaccesibility. This study analyzed the impact of gum Arabic (GA), bamboo fiber (BF), native corn starch, starch substituted with octenylsuccinic groups, pea fiber, and maltodextrin on the in vitro bioaccessibility of vitamin C (VC), total phenols (TP), and ß-carotene, as well as on the antioxidant capacity during the freeze-drying and in vitro digestion of an orange puree. Amongst the formulations studied, GA+BF was the most effective for phytochemicals protection of the freeze-dried orange puree during the intestinal stage of digestion, resulting in a higher TP and VC bioaccessibility (59% and 36%, respectively).

[EN] Purpose A healthy and easy-to-use orange snack obtained from the freeze-dried orange pulp puree is proposed. Once the commercial packaging of the snack has been opened, the effect of conventional home storage temperature on its physicochemical properties and on the content of bioactive compounds has been studied. This research aims to recommend the consumer, and therefore the manufacturer, the best conditions for home storage of this product, keeping its nutritional quality and antioxidant capacity, as well as maintaining its colour and crispness. Design/methodology/approach The water content, water activity, hygroscopicity, crispness, colour, vitamin C, beta-carotene, total phenolic compounds and antioxidant activity were characterised both when the orange snack was newly obtained and after one, two and six months of storage inside zipper bags, at 4 and 20 oC. Findings The results indicated that, in these conditions, the orange snack increased its water content, causing a loss in both its porosity and its characteristic crispness. Nevertheless, the bioactive compounds remained stable throughout the storage period, with the exception of beta-carotene, the content of which decreased markedly when the orange snack was stored at 20 oC. Originality/value Few studies have evaluated the stability of food products during home storage. The findings showed that the maximum storage time to ensure a proper texture of the orange snack studied is between two and six months, both at 4 and 20 oC. However, from the point of view of the conservation of both vitamin C and, especially, of beta-carotene, it is recommended that this product be stored in refrigeration.

[EN] Freeze-drying is a good alternative means of obtaining fruit products, with a significant amount of thermolabile bioactive compounds. Despite the excellent benefits, this method provides the dehydrated product, and its main drawback is its high cost due to the duration of the process. Heat may be applied to the shelf so as to shorten the process time, as long as this does not affect the quality of the product. In this study, the impact of the freeze-drying shelf temperature, 30 and 50¿°C, on the bioactive compounds of the product obtained from an orange juice formulated with gum Arabic and bamboo fibre has been considered, as has the temperature¿s effect on the porosity, colour and mechanical properties of the cake and on the flowability and the rehydration capacity of the powder, together with the sensory evaluation of the rehydrated product. The results obtained point to 50¿°C as being the recommended temperature for the freeze-drying of this product. This temperature shortens the process time by 64%, promotes the vitamin C content with no effect on the total phenols and carotenoids, leads to the cakes having better mechanical properties and does not affect the flowability and the rehydration behaviour of the powdered product.

[EN] The high nutritional and functional value of fruits justifies the use of freeze-drying to obtain high value-added products. As to identify in-line the drying end point, the usefulness of temperature evolution of a grapefruit puree, added or not with gum Arabic and bamboo fibre, when applying 20 or 40 oC as shelf temperature has been investigated. The obtained results point for the monitoring of the product's heating rate as to identify the end of sublimation in the sample, coinciding with the time this rate starts to decrease. On the other hand, the end point of the drying step of the freeze-drying process, optimised in terms of duration, is proposed to be related to the sample reaching a certain target temperature which does not necessarily match with the temperature of the chamber. In the concrete conditions of this study, it seems to be between 20 and 40 oC. As for the variables considered, the biopolymers added to the grapefruit puree did not affect the duration of the process and to increase the freeze-drier shelves temperature made it possible to reduce processing time by 40%.

Freeze-drying is a good alternative means of obtaining fruit products, with a significant amount of thermolabile bioactive compounds. Despite the excellent benefits, this method provides the dehydrated product, and its main drawback is its high cost due to the duration of the process. Heat may be applied to the shelf so as to shorten the process time, as long as this does not affect the quality of the product. In this study, the impact of the freeze-drying shelf temperature, 30 and 50 °C, on the bioactive compounds of the product obtained from an orange juice formulated with gum Arabic and bamboo fibre has been considered, as has the temperature’s effect on the porosity, colour and mechanical properties of the cake and on the flowability and the rehydration capacity of the powder, together with the sensory evaluation of the rehydrated product. The results obtained point to 50 °C as being the recommended temperature for the freeze-drying of this product. This temperature shortens the process time by 64%, promotes the vitamin C content with no effect on the total phenols and carotenoids, leads to the cakes having better mechanical properties and does not affect the flowability and the rehydration behaviour of the powdered product.

[ES] La industria de la transformación de las frutas en general y de las naranjas en particular nace de la necesidad de la utilización de dicha fruta que, por su carácter perecedero, se perdería. Estas industrias, como por ejemplo las del zumo de naranja, generan grandes cantidades de residuos que, por sus características nutricionales, se utilizan sobre todo para la alimentación animal. Este uso, sin embargo, es limitado y podría ampliarse a la alimentación humana con valor añadido, debido a la riqueza de los subproductos en cuanto a fibra o compuestos bioactivos, como la vitamina C (VC), con propiedades antioxidantes y funcionales. Este producto podría utilizarse para la obtención de nuevos alimentos o para la obtención de extractos. Por otra parte, por su carácter perecedero debido a su composición, alto contenido en agua, sobre todo, se hace imprescindible su conservación mediante tecnologías como por ejemplo la deshidratación. En esta investigación se pretende utilizar la liofilización, tecnología muy conocida en el grupo de investigación donde se va a realizar este trabajo y acreditada por su bajo impacto en los compuestos bioactivos que se degradan fácilmente si se utiliza otro proceso más convencional como puede ser el secado por aire caliente. En este sentido, el objetivo de este estudio es ver la influencia de la liofilización de los subproductos obtenidos tras la extracción del zumo de la naranja en la estabilidad de la vitamina C y estudiar cómo influye la matriz. Para ello, se pretende comparar el contenido de VC de los subproductos (con incorporación o no de biopolímeros estabilizantes) liofilizados y el de los extractos de VC (con incorporación o no de biopolímeros estabilizantes) también liolifizados., [EN] The fruit processing industry in general, and oranges in particular, arose from the need to use such fruit, which, due to its perishable nature, would be lost. These industries, such as those of orange juice, generate large amounts of waste that, due to their nutritional characteristics, are mainly used for animal feed. This use, however, is limited and could be extended to human consumption with added value, due to the richness of by-products in terms of fibre or bioactive compounds, such as vitamin C, with antioxidant and functional properties. This product could be used to obtain new foods or to obtain extracts. On the other hand, due to its perishable nature, its preservation through technologies such as dehydration is essential. Freeze drying was used in this research. In this sense, the objective of this study has been to see the influence of freeze drying of the by-products obtained after the extraction of orange juice on the stability of vitamin C and to study how the matrix influences. For this, the content of vitamin C of the freeze dried by-products and vitamin C extracts have been compared. The results indicate that the by-products have a high content of vitamin C and that for it better preservation, freeze drying of the by-product and subsequent extraction of the compound would be recommended, rather than freeze drying of the previously extracted compound.

[EN] In addition to colour, one of the most important qualifies of a snack-type product is its crunchy texture. A freeze-dried fruit snack is characterised by its low water content, which creates the problem of a loss of crunchiness related to its low glass transition temperature (Tg). In this sense, a common technique with which to increase the Tg of these types of products is to add different biopolymers. However, these compounds can, at the same time, affect the colour and texture of the product. In this study, different biopolymers have been tested in order to discover their similarities or differences in terms of hygroscopicity, antiplasticising character, colour and impact on the mechanical properties of a freeze-dried orange snack formulated from their different mixtures. Gum Arabic, maltodextrin, starch modified with octenylsuccinic anhydride, pea fibre, bamboo fibre and native corn starch have been selected as biopolymers. The impact of any of them on the studied properties can be confirmed, without any of them being more or less effective than the others.

[EN] Freeze-drying provides high quality foods, despite the long time involved in the operation. Shortening the process time by increasing the heat supplied for sublimation to occur could affect the product quality. In this study, the impact of adding gum Arabic and bamboo fiber to a grapefruit puree and of raising the shelf temperature to 40 degrees C during freeze-drying has been considered. The increase in temperature allows a 57.5% time reduction and promotes a porosity increase without any impact on the cakes color and vitamin C content. The addition of biopolymers does not affect the drying kinetics and allows a crunchier and firmer cake to be obtained, despite the color changes and the fact that vitamin C becomes less available. In conclusion, raising the shelf temperature to 40 degrees C significantly reduces the freeze drying time without noticeably impairing the product, and the addition of biopolymers improves the product characteristics without adversely impacting upon drying times.

[ES] Los patrones de consumo de alimentos entre la población son cada vez más exigentes en lo que se refiere a la ingesta de productos naturales, saludables, mínimamente procesados y de máxima calidad. Esto obliga al continuo desarrollo de nuevos productos que satisfagan las expectativas del consumidor. Las industrias agroalimentarias, que se ocupan de ello, necesitan una gran cantidad de recursos materiales e inmateriales para el desarrollo de su actividad que, a su vez, genera grandes volúmenes de residuos. No obstante, en su interés por contribuir a la sostenibilidad del planeta, es ya patente su apuesta por la innovación basada en los principios de la economía circular. Entre ellos se incluye la generación de actividad económica a partir de la utilización de recursos de origen biológico como materia prima. En este estudio se ha trabajado con el coproducto generado en las industrias de zumo de naranja (CoZ). Se han analizado aquellas propiedades físicas del coproducto liofilizado, tanto en torta como en polvo, que pueden aportar información útil para poder proponer diferentes usos destinados a la alimentación humana. Al mismo tiempo, se ha estudiado la conveniencia de añadir goma arábiga y fibra de bambú como biopolímeros estabilizadores del producto deshidratado. En ambos casos se ha caracterizado la densidad aparente, porosidad, color y textura de la torta, así como la densidad aparente, porosidad, higroscopicidad, ángulo de reposo, compresibilidad y mojabilidad del polvo, además de su isoterma de sorción. Los resultados obtenidos permiten recomendar la incorporación de biopolímeros a fin de mejorar las propiedades analizadas. En concreto, disminuyen la higroscopicidad, mejoran la estabilidad de su estructura, dan lugar a una torta menos porosa, más resiente a la fractura y con un color más puro, y aumentan su mojabilidad., [EN] Food consumption patterns among the population are increasingly demanding for natural, healthy, minimally processed and top-quality foods. This forces the continuous development of new products that meet consumer expectations. The agri-food industries, which deal with this, need a large amount of material and intangible resources for the development of their activity, which, in turn, generates large volumes of waste. However, in its interest to contribute to the sustainability of the planet, its commitment to innovation based on the principles of the circular economy is already clear. These include the generation of economic activity from the use of resources of biological origin as raw material. This study has studied the by-product generated in the orange juice industries (CoZ). Those physical properties of the freeze-dried co-product, both in cake and powder, that can provide useful information to propose different uses for human consumption have been analysed. At the same time, the convenience of adding gum arabic and bamboo fiber as stabilizing biopolymers of the dehydrated product has been studied. In both cases, the apparent density, porosity, color and texture of the cake have been characterized, as well as the apparent density, porosity, hygroscopicity, angle of repose, compressibility and wettability of the powder, in addition to its sorption isotherm. The results obtained allow recommending the incorporation of biopolymers in order to improve the properties analysed. Specifically, they decrease hygroscopicity, improve the stability of its structure, give rise to a less porous cake, more resistant to fracture and with a purer color, and increase its wettability.

[ES] A pesar de que la fruta tiene claros efectos positivos sobre la salud, en la actualidad, su consumo se ve limitado por diferentes motivos, entre ellos la falta de practicidad para su ingesta. Ante esta problemática, la administración trata de promover el consumo de fruta, lo que necesariamente ha de ir ligado a la actividad de I+D+i de la industria agroalimentaria. En los últimos tiempos, lo que se ha venido en llamar la snackificación, está generando nuevas oportunidades de mercado para la comida tradicional ofertada en modo snack. Desde este punto de vista, los snacks de fruta se muestran como una oferta de alimento saludable y cómoda de consumir. No obstante, la industria también se enfrenta al reto de la gestión de los subproductos que genera. En el caso de las frutas en general y, de la naranja, en particular, la obtención de un snack, a partir de, por ejemplo, el puré de ésta, supone generar una gran cantidad de corteza. Sin embargo, dado que esta corteza es también una fuente importante de fibra y otros compuestos bioactivos, puede resultar interesante integrar esta biomasa en las líneas de producción. En este trabajo pretende planificar un estudio que permita conocer la viabilidad del uso del co-producto del puré de naranja liofilizado en polvo en la formulación de un snack, además de proponer la metodología para llevarlo a cabo. La hipótesis de partida es que la presencia de polisacáridos de alto peso molecular en el exocarpio del fruto pueda contribuir, bien a nivel estérico o bien aumentando la temperatura de transición vítrea (Tg) del producto, a minimizar los problemas de colapso estructural que presentan los productos de fruta deshidratada. Para ello, en primer lugar, es necesario conocer sus relaciones Tg-humedad-actividad del agua. Por otra parte, habrá que diseñar una serie de formulaciones del snack de las que habrá que conocer, no sólo sus propiedades, sino también su estabilidad. Para el diseño de estas formulaciones habrá que tener en cuent, [EN] Although fruit has clearly positive effects in human health, currently, fruit consumption has decreased for different reasons; one of them is the lack of practicality that supposes his consumption. Being aware of this problem, the Administration is trying to promote fruits consumption, this promotion is necessarily linked to I+D+I activity of food industry. In recent times, snacks production process, has been producing new market opportunities for traditional food that has been offered as snacks. From this point of view, fruits snacks are showed as a healthy and convenient food supply. However, industry also faces the challenge of managing the by-products generated. In the case of fruits, particularly the orange, obtaining a snack from, par example, orange puree supposes the generation of a large amount of orange peel. However, knowing that orange peel is also an important source of fiber and other bioactive compounds, incorporating this biomass to the production lines could by an interesting possibility. This work aims to plan a study that would allow us to know the viability of using the freeze-dried powdered orange co-product in a snack formulation, in addition, this work propose a working methodology. The initial hypothesis says that the presence of high molecular weight polysaccharides in the exocarp of the fruit can contribute, either at the steric level or by increasing the vitreous transition temperature (Tg) of the product, to minimize the problems of structural collapse presented at dehydrated fruit products. To do this, in the first place, it will be necessary to know their Tg-humidity-water activity relationships. On the other hand, it will be necessary to design a series of snack formulations of which we will have to know, not only their properties, but also their stability. For the design of these formulations, the composition of the different parts of the orange must be considered. With this information, the powdered peel, alone or mixed with oth

[EN] The production of powdered food is an increasingly important industry due to the high stability and easy handling of those products. The aim of this work was to evaluate the effect of the addition of gum arabic in combination with bamboo fiber or cactus cladode mucilage on the physicochemical and antioxidant properties of orange pulp powder obtained by freeze drying. Additionally, the stability of the powders after 10 months of storage was evaluated. The following determinations were performed: moisture content and hygroscopicity, glass transition temperature, total phenolic and vitamin C content, antiradical and antioxidant capacities, compression test, color and FESEM analysis. The results showed that the inclusion of gum arabic in combination with bamboo fiber or cactus cladode mucilage to the orange puree previous to freeze drying improved their chemical and physical stability. The combination gum arabic- bamboo fiber resulted a better option than the system gum arabic cactus cladode mucilage.