6,742 research outputs found

    Effect of swelling agent treatment on grape fruit quality and the application of electronic nose identification detection

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    The swelling agent is a plant growth regulator that alters the composition and content of nutrients and volatile gases in the fruit. To identify whether grape fruit had been treated with swelling agent, the odor information and quality indexes of grape berries treated with different concentrations of swelling agent were examined by using electronic nose technology and traditional methods. The contents of soluble sugars, soluble solids, soluble proteins and vitamin C were significantly increased in N-(2-chloro-4-pyridyl)-N’-phenylurea (CPPU) treated fruit. The contents of hexanal, (E)-2-hexenal, and nonanal aldehydes decreased significantly. Similarly, the levels of phenyl ethanol, 1-octanol, ethanol, and ethyl acetate alcohols and esters also decreased noticeably. Additionally, the levels of damascenone, linalool, and geraniol ketones and terpenoids decreased. However, the contents of benzaldehyde, D-limonene, acetic acid and hexanoic acid increased. In addition, the electrical signals generated by the electronic nose (e-nose) were analyzed by linear discriminant analysis (LDA), support vector machine (SVM) and random forest (RF). The average recognition rate of SVM was 94.4%. The results showed that electronic nose technology can be used to detect whether grapes have been treated with swelling agent, and it is an economical and efficient detection method

    Genome-wide identification of the expansin gene family in netted melon and their transcriptional responses to fruit peel cracking

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    IntroductionFruit cracking not only affects the appearance of netted melons (Cucumis melo L. var. reticulatus Naud.) but also decreases their marketability.MethodsHerein, to comprehensively understand the role of expansin (EXP) proteins in netted melon, bioinformatics methods were employed to discover the EXP gene family in the melon genome and analyze its characteristic features. Furthermore, transcriptomics analysis was performed to determine the expression patterns of melon EXP (CmEXP) genes in crack-tolerant and crack-susceptible netted melon varieties.DiscussionThirty-three CmEXP genes were identified. Chromosomal location analysis revealed that CmEXP gene distribution was uneven on 12 chromosomes. In addition, phylogenetic tree analysis revealed that CmEXP genes could be categorized into four subgroups, among which the EXPA subgroup had the most members. The same subgroup members shared similar protein motifs and gene structures. Thirteen duplicate events were identified in the 33 CmEXP genes. Collinearity analysis revealed that the CmEXP genes had 50, 50, and 44 orthologous genes with EXP genes in cucumber, watermelon, and Arabidopsis, respectively. However, only nine orthologous EXP genes were observed in rice. Promoter cis-acting element analysis demonstrated that numerous cis-acting elements in the upstream promoter region of CmEXP genes participate in plant growth, development, and environmental stress responses. Transcriptomics analysis revealed 14 differentially expressed genes (DEGs) in the non-cracked fruit peels between the crack-tolerant variety ‚ÄėXizhoumi 17‚Äô (N17) and the crack-susceptible variety ‚ÄėXizhoumi 25‚Äô (N25). Among the 14 genes, 11 were upregulated, whereas the remaining three were downregulated in N17. In the non-cracked (N25) and cracked (C25) fruit peels of ‚ÄėXizhoumi 25‚Äô, 24 DEGs were identified, and 4 of them were upregulated, whereas the remaining 20 were downregulated in N25. In the two datasets, only CmEXPB1 exhibited consistently upregulated expression, indicating its importance in the fruit peel crack resistance of netted melon. Transcription factor prediction revealed 56 potential transcription factors that regulate CmEXPB1 expression.ResultsOur study findings enrich the understanding of the CmEXP gene family and present candidate genes for the molecular breeding of fruit peel crack resistance of netted melon

    Study on the Quality Changes of Coffee Malt Premixed Powder Applied to Baking Products during Storage

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    In order to study the quality change of coffee malt premixed powder with the extension of storage period, the coffee malt premixed powder was stored at the environment where the temperature is 25 ‚ĄÉ and 35 ‚ĄÉ, respectively, and the relative humidity is 50% respectively. Its moisture, fatty acid value and falling value were monitored during the whole storage period. The volatile compounds were separated and identified by solid phase microextraction accompanying gas chromatography-mass spectrometry during the whole storage period. The results demonstrated that with the extension of storage period, the overall moisture content shows a falling trend, while the fatty acid value and falling value show an overall rising trend. The higher the storage temperature, the more significant the change is 41 kinds of main volatile compounds of coffee malt ready mixed powder were identified. It mainly includes 13 kinds of aldehydes, 15 kinds of heterocycles, 7 kinds of esters, 4 kinds of alcohols and 2 kinds of ketones. Among them, the relative concentration of aldehydes (n-hexanal, nonanal, trans-2-nonenal) showed an increasing trend with the extension of storage period

    Advancing tree genomics to future proof next generation orchard production

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    The challenges facing tree orchard production in the coming years will be largely driven by changes in the climate affecting the sustainability of farming practices in specific geographical regions. Identifying key traits that enable tree crops to modify their growth to varying environmental conditions and taking advantage of new crop improvement opportunities and technologies will ensure the tree crop industry remains viable and profitable into the future. In this review article we 1) outline climate and sustainability challenges relevant to horticultural tree crop industries, 2) describe key tree crop traits targeted for improvement in agroecosystem productivity and resilience to environmental change, and 3) discuss existing and emerging genomic technologies that provide opportunities for industries to future proof the next generation of orchards

    Breeding Melons for Resistance to Viral and Fungal Diseases. Exploiting the Multi-Resistant Accession TGR-1551

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    [ES] Las cucurbit√°ceas son la segunda familia de hort√≠colas m√°s importante a nivel mundial, solo por detr√°s de las solan√°ceas. Tradicionalmente su cultivo se ha llevado a cabo en las zonas templadas del planeta. Sin embargo, las condiciones de cambio clim√°tico, el comercio internacional y los modelos de agricultura intensiva favorecen la aparici√≥n de nuevas virosis y enfermedades f√ļngicas en zonas donde antes no estaban presentes. En este sentido, resulta esencial el monitoreo peri√≥dico de las principales zonas productoras, para as√≠ poder detectar los virus y hongos emergentes en cada territorio y adaptar los programas de mejora a los objetivos espec√≠ficos de cada zona. En el caso concreto del mel√≥n (Cucumis melo) existe una gran variabilidad intraespec√≠fica que puede servir como fuente de alelos de resistencia frente a estos pat√≥genos. Sin embargo, las fuentes de resistencia suelen encontrarse dentro del germoplasma silvestre, normalmente originario de √Āfrica o Asia, y en el que el nivel de domesticaci√≥n es reducido. Para un mejor aprovechamiento de las accesiones resistentes, resulta necesario un estudio del control gen√©tico de los caracteres de inter√©s, que permita localizar las regiones asociadas a la resistencia y dise√Īar marcadores moleculares asociadas a las mismas. Esto facilita los programas de mejora orientados a la introgresi√≥n de las resistencias manteniendo el fondo gen√©tico de las variedades de inter√©s En la presente tesis doctoral, durante las campa√Īas de verano de 2019 y 2020, se ha llevado a cabo un estudio de la incidencia y diversidad gen√©tica de 9 especies virales potencialmente limitantes para el cultivo de cucurbit√°ceas en el sur este espa√Īol. Se ha podido observar que los virus transmitidos por pulgones son prevalentes frente a los transmitidos por mosca blanca. Dentro del primer grupo destac√≥ la presencia de watermelon mosaic virus (WMV), cucurbits aphid borne yellows virus (CABYV) y cucumber mosaic virus (CMV), ya que fueron detectados en todas las zonas y cultivos estudiados, apareciendo frecuentemente en infecciones mixtas. Moroccan watermelon mosaic virus (MWMV) y tomato leaf curl New Delhi virus (ToLCNDV) tambi√©n fueron detectados en algunas zonas, pero con porcentajes de infecci√≥n m√°s bajos y normalmente en infecciones mixtas con WMV. Los an√°lisis filogen√©ticos de los distintos aislados encontrados ha permitido la identificaci√≥n de 7 nuevos perfiles moleculares de WMV y de aislados recombinantes de CMV, lo que es consistente con los resultados obtenidos en otros pa√≠ses y pone de manifiesto la gran variabilidad de estos pat√≥genos. Las accesiones silvestres de mel√≥n recogidas en distintos bancos de germoplasma son un valioso recurso para los programas de mejora gen√©tica frente a estreses bi√≥ticos. La accesi√≥n africana TGR-1551 ha sido descrita previamente como resistente a WMV, CYSDV (cucurbit yellow stunting disorder virus), CABYV y el hongo Podosphaera xanthii (Px, razas 1, 2 y 5) agente causal del o√≠dio en mel√≥n. Adem√°s, es tolerante a la mosca blanca (Bemisia tabaci) y portadora del gen Vat (virus aphid transmission), el cual limita la transmisi√≥n de virus por pulg√≥n. Por lo tanto, esta accesi√≥n constituye una buena fuente de alelos de resistencia y, al poder utilizar un √ļnico parental donante, su uso acortar√≠a los programas de mejora. En el marco de la presente tesis doctoral, mediante el desarrollo de poblaciones segregantes de mapeo y el aprovechamiento de las tecnolog√≠as de genotipado masivo se han podido cartografiar los QTLs asociados a la resistencia a CYSDV derivados de esta entrada. En el caso de la resistencia a CYSDV, se han detectado dos QTL en el cromosoma 5. El primero de ellos es de efecto mayor y herencia dominante, estando asociado al desarrollo de s√≠ntomas. El segundo QTL, de efecto menor y tambi√©n de herencia dominante, no confiere resistencia por s√≠ mismo y est√° asociado a la carga viral durante la infecci√≥n. Siguiendo una estrategia similar se han podido cartografiar y estrecha[CA] Les cucurbit√†cies s√≥n la segona fam√≠lia d'hort√≠coles m√©s important a nivell mundial, nom√©s per darrere de les solan√†cies. Tradicionalment el seu cultiu s'ha dut a terme a les zones temperades del planeta. No obstant aix√≤, les condicions de canvi clim√†tic, el comer√ß internacional i els models d'agricultura intensiva afavoreixen l'aparici√≥ de noves virosis i malalties f√ļngiques en zones on abans no estaven presents. En aquest sentit, resulta essencial el monitoratge peri√≤dic de les principals zones productores, per a d'aquesta manera, poder detectar els virus i fongs emergents en cada territori i adaptar els programes de millora als objectius espec√≠fics de cada zona. En el cas concret del mel√≥ (Cucumis melo) existeix una gran variabilitat intraespec√≠fica que pot servir com a font d'al¬∑lels de resist√®ncia enfront d'aquests pat√≤gens. No obstant aix√≤, les fonts de resist√®ncia solen trobar-se dins del germoplasma silvestre, normalment originari d'√Äfrica o √Äsia, i en el qual el nivell de domesticaci√≥ √©s redu√Įt. Per a un millor aprofitament de les accessions resistents, resulta necessari un estudi del control gen√®tic dels car√†cters d'inter√©s, que permeta localitzar les regions associades a la resist√®ncia i dissenyar marcadors moleculars associats a aquestes. Aix√≤ facilita els programes de millora orientats a la introgressi√≥ de les resist√®ncies mantenint el fons gen√®tic de les varietats d'inter√©s. En la present tesi doctoral, durant les campanyes d'estiu de 2019 i 2020, s'ha dut a terme un estudi de la incid√®ncia i diversitat gen√®tica de nou esp√®cies virals potencialment limitants per al cultiu de cucurbit√†cies en el sud-est espanyol. S'ha pogut observar que els virus transmesos per pugons s√≥n prevalents enfront dels transmesos per mosca blanca. Dins del primer grup va destacar la pres√®ncia de watermelon mosaic virus (WMV), cucurbits aphid born yellows virus (CABYV) i cucumber mosaic virus (CMV), ja que van ser detectats en totes les zones i cultius estudiats, apareixent sovint en infeccions mixtes. Moroccan watermelon mosaic virus (MWMV) i tomatoleaf curl New Delhi virus (ToLCNDV) tamb√© van ser detectats en algunes zones, per√≤ amb percentatges d'infecci√≥ m√©s baixos i normalment en infeccions mixtes amb WMV. Les an√†lisis filogen√®tiques dels diferents a√Įllats trobats ha perm√©s la identificaci√≥ de set nous perfils moleculars de WMV i d'a√Įllats recombinants de CMV, la qual cosa √©s consistent amb els resultats obtinguts en altres pa√Įsos i posa de manifest la gran variabilitat d'aquests pat√≤gens. Les accessions silvestres de mel√≥ recollides en diferents bancs de germoplasma s√≥n un valu√≥s recurs per als programes de millora gen√®tica enfront d'estressos bi√≤tics. L'accessi√≥ africana *TGR-1551 ha sigut descrita pr√®viament com a resistent a WMV, CYSDV (cucurbit yellow stunting disorder virus), CABYV i el fong Podosphaera xanthii (Px, races 1, 2 i 5) agent causal de l'o√Įdi en mel√≥. A m√©s, √©s tolerant a la mosca blanca (Bemisia tabaci) i portadora del gen Vat (virus aphid transmission), el qual limita la transmissi√≥ de virus per pug√≥. Per tant, aquesta accessi√≥ constitueix una bona font d'al¬∑lels de resist√®ncia i, en poder utilitzar un √ļnic parental donant, el seu √ļs acurtaria els programes de millora. En el marc de la present tesi doctoral, mitjan√ßant el desenvolupament de poblacions segregants de mapatge i l'aprofitament de les tecnologies de genotipat massiu s'ha pogut cartografiar els QTLs associats a la resist√®ncia a CYSDV derivats d'aquesta entrada. En el cas de la resist√®ncia a CYSDV, s'han detectat dues QTL en el cromosoma cinc. El primer d'ells √©s d'efecte major i her√®ncia dominant, estant associat al desenvolupament de s√≠mptomes. El segon QTL, d'efecte menor i tamb√© d'her√®ncia dominant, no confereix resist√®ncia per si mateix i est√† associat a la c√†rrega viral durant la infecci√≥. Seguint una estrat√®gia similar s'han pogut cartografiar i estr√©nyer els *QTLs de resist√®ncia enfront de Px. En aquest cas es tracta d'una epist√†sia dominant-re[EN] Cucurbits represent the second most important horticultural family worldwide, second only the Solanaceae family. Traditionally, their cultivation has been concentrated in temperate regions across the globe. However, climate change conditions, international trade, and intensive agricultural practices are contributing to the emergence of new viral and fungal diseases in regions where they were previously absent. In this regard, it is crucial to regularly monitor major production areas to detect emerging viruses and fungi specific to each region. This monitoring allows for the adaptation of breeding programs to the unique goals of each area. In the case of melon (Cucumis melo), it exists significant intraspecific variability that can serve as a source of resistance alleles against these pathogens. However, sources of resistance are often found within wild germplasm, typically originating from Africa or Asia, and characterized by limited domestication. To better utilize these resistant accessions, a study of the genetic control of desirable traits is necessary. This study aims to locate regions associated with resistance and design molecular markers linked to these regions. Such an approach streamlines breeding programs focused on introgressing resistance traits while preserving the genetic background of the desired varieties. During the summer campaigns of 2019 and 2020, this doctoral thesis conducted a study on the incidence and genetic diversity of nine viral species potentially affecting cucurbit cultivation in southeastern Spain. It was observed that viruses transmitted by aphids were more prevalent than those transmitted by whiteflies. Within the first group, the presence of watermelon mosaic virus (WMV), cucurbits aphid borne yellows virus (CABYV), and cucumber mosaic virus (CMV) stood out, as they were detected in all the studied areas and crops, often in mixed infections. Moroccan watermelon mosaic virus (MWMV) and tomato leaf curl New Delhi virus (ToLCNDV) were also detected in some areas but with lower infection percentages, typically in mixed infections with WMV. Phylogenetic analyses of the found isolates have identified seven new molecular profiles of WMV and recombinant CMV isolates, which is consistent with results from other countries, highlighting the extensive variability of these pathogens. Wild melon accessions preserved in various germplasm banks represent a valuable resource for breeding programs against biotic stresses. The African accession TGR-1551 has been previously described as resistant to WMV, CYSDV (cucurbit yellow stunting disorder virus), CABYV, and the fungus Podosphaera xanthii (Px, races 1, 2, and 5), which causes powdery mildew in melons. Additionally, it is tolerant to whiteflies (Bemisia tabaci) and carries the Vat gene (Virus Aphid Transmission), limiting virus transmission by aphids. Therefore, this accession constitutes as an excellent source of resistance alleles, and its use, as a single donor parent, can expedite breeding programs. Within the scope of this doctoral thesis, through the development of segregating mapping populations and the utilization of high-throughput genotyping technologies, the QTLs associated with CYSDV resistance from this accession have been mapped. In the case of CYSDV resistance, two QTLs have been detected on chromosome 5. The first of these, with major effects and dominant inheritance, is associated with symptom development. The second QTL, with minor effects and also dominant inheritance, does not confer resistance by itself and is linked to viral load during infection. A similar strategy was employed to map and narrow down the QTLs for resistance against Px. In this case, it involves a dominant-recessive epistasis, with the recessive gene located on chromosome 12 and the dominant gene on chromosome 5, specifically in the same region where the major CYSDV resistance QTL is located. Regarding resistance against WMV, previous studies conducted by the researchThis research was funded by the Spanish Ministerio de Ciencia e Innovaci√≥n (MCIN/AEI/10.13039/501100011033), grant number PID2020-116055RB (C21 and C22), and by the Conselleria d‚ÄôEducaci√≥, Investigaci√≥, Cultura i Esports de la Generalitat Valenciana, grant number PROMETEO/2021/072 (to promote excellence groups, cofinanced with FEDER funds). M.L. is a recipient of a predoctoral fellowship (PRE2018-083466) of the Spanish Ministerio de Ciencia, Innovaci√≥n y Universidades co-financed with FSE funds.L√≥pez Mart√≠n, M. (2023). Breeding Melons for Resistance to Viral and Fungal Diseases. Exploiting the Multi-Resistant Accession TGR-1551 [Tesis doctoral]. Universitat Polit√®cnica de Val√®ncia. https://doi.org/10.4995/Thesis/10251/20206

    Effects of Pectinase Pre-Treatment on the Physicochemical Properties, Bioactive Compounds, and Volatile Components of Juices from Different Cultivars of Guava

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    In this study, the physicochemical properties, antioxidant capacity, and volatile compounds of the juices of different guava cultivars before and after pectinase treatment were evaluated. The results showed that the guava juice of the small fragrant (SF) cultivar exhibited the highest ascorbic acid concentration (1761.09 mg/L), and the highest contents of total phenolics (329.52 mg GAE/L) and total flavonoids (411.13 mg RE/L) were both found in the juice of the watermelon red (WR) cultivar. After pectinase treatment, the juice yield and the titratable acid, sugar components, total phenolics and total flavonoids, and antioxidant capacity levels of the guava juices were all higher than those of the non-pectinase group. However, lower sensory evaluation scores were obtained in the pectinase-treated guava juices. Aldehydes and terpenoids were the main flavor components in the guava juices, which were responsible for the aroma of the juice, while their relative contents were different in the four cultivar guava juices. Furthermore, pectinase treatment could change the amounts and relative contents of volatile compounds in the guava juice. During the pectinase treatment process, the relative contents of the main aroma constituents in the guava juices were significantly decreased. The findings of this research provide valuable information for the processing of guava juice

    Multi-product biorefinery from bay tree pruning for advanced materials production and application

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    Debido a los desaf√≠os econ√≥micos y ambientales a los que se enfrenta la sociedad actual, los estados miembros de las Naciones Unidas propusieron en 2015 los 17 Objetivos del Desarrollo Sostenible (ODS). Estos objetivos se centran en promover formas para lograr la sostenibilidad en todas las √°reas posibles (agua, energ√≠a, clima, industrias, econom√≠a, ciencia y tecnolog√≠a). De esta manera, se hace inminente la necesidad de transici√≥n hacia la bioeconom√≠a. La bioeconom√≠a desempe√Īa un papel importante para alcanzar el desarrollo sostenible, ya que su principal objetivo es que la econom√≠a actual se base en el uso de recursos renovables que puedan ser convertidos en productos de alto valor a√Īadido. El agotamiento de los recursos f√≥siles, as√≠ como la fluctuaci√≥n en los precios del petr√≥leo y los problemas de contaminaci√≥n ambiental, exigen la b√ļsqueda de una nueva perspectiva en la que el uso de recursos renovables sea la base. En este sentido, las biorrefiner√≠as de materiales lignocelul√≥sicos surgen como una soluci√≥n brillante. En los sistemas de biorrefiner√≠a se valorizan diferentes tipos de residuos lignocelul√≥sicos para obtener productos √ļtiles, eficientes y valiosos que ayuden a lograr el tan deseado desarrollo sostenible. De esta forma, la presente Tesis Doctoral ha abordado diferentes caminos para la valorizaci√≥n de los residuos de la poda de laurel (Laurus nobilis L.) desde el punto de vista de la biorrefiner√≠a, mediante su transformaci√≥n, fraccionamiento y aplicaci√≥n en la preparaci√≥n de nuevos materiales y productos de alto valor a√Īadido. La modificaci√≥n qu√≠mica de los residuos lignocelul√≥sicos mediante reacciones de licuefacci√≥n ha surgido en los √ļltimos a√Īos como una t√©cnica novedosa para la preparaci√≥n de materiales compuestos, acrilatos y poliuretanos basados en compuestos naturales. Los polioles que se utilizan com√ļnmente en la industria del poliuretano son de origen petroqu√≠mico. Por lo tanto, la preparaci√≥n de polioles naturales con caracter√≠sticas similares a los derivados del petr√≥leo podr√≠a abrir un camino alternativo y sostenible en el mercado de los poliuretanos. En este sentido, en la Publicaci√≥n I de esta Tesis Doctoral se describe la s√≠ntesis de polioles a partir de residuos de la poda de laurel, sin fraccionamiento previo, y su aplicaci√≥n para la preparaci√≥n de espumas de poliuretano aislantes. El poliol obtenido demostr√≥ propiedades similares (n√ļmero de grupos hidroxilo, viscosidad y peso molecular) o incluso mejores que los polioles disponibles actualmente en el mercado, adem√°s de reportar un alto rendimiento de licuefacci√≥n. Por tanto, el poliol era perfectamente aplicable para la preparaci√≥n de las mencionadas espumas. Las espumas aislantes se prepararon teniendo en cuenta varios par√°metros que suelen influir en la estructura final de estos materiales: el tipo de diisocianato empleado (MDI o TDI) y la adici√≥n de agua como agente espumante f√≠sico. Seg√ļn los resultados obtenidos, las espumas preparadas con TDI mostraron una formulaci√≥n √≥ptima a una relaci√≥n molar NCO/OH (RNCO/OH) de 1,1 (40% en peso de poliol de residuos de la poda de laurel y sin la adici√≥n del agente espumante) en t√©rminos de densidad aparente y propiedades mec√°nicas (resistencia a la compresi√≥n y m√≥dulo de Young). En el caso de las espumas preparadas con MDI, se encontr√≥ que la formulaci√≥n √≥ptima era de RNCO/OH 0,63 (50% en peso de poliol de residuos de la poda de laurel y con adici√≥n del agente espumante). Todas las espumas formuladas ten√≠an una morfolog√≠a de celdas peque√Īas y cerradas y una mayor estabilidad t√©rmica con la presencia del poliol sintetizado. Los resultados obtenidos en este estudio han permitido sugerir al poliol de residuos de la poda de laurel como un sustituto adecuado de los poliuretanos empleados habitualmente. Por otro lado, tradicionalmente, la aplicaci√≥n m√°s conocida del laurel ha sido a trav√©s de su aceite esencial en cocina y farmacia, a pesar de haber demostrado buenos resultados en el tratamiento de enfermedades gracias a sus propiedades antioxidantes. Estos extractos naturales suelen obtenerse mediante extracci√≥n convencional Soxhlet, lo que requiere grandes vol√ļmenes de disolvente de extracci√≥n, as√≠ como tiempos de extracci√≥n largos. Yendo un paso m√°s all√°, la Publicaci√≥n II se centra en la optimizaci√≥n de la obtenci√≥n del extracto natural de las hojas de laurel mediante metodolog√≠as de intensificaci√≥n respetuosas con el medio ambiente. En este sentido, se estableci√≥ y aplic√≥ un protocolo de pretratamiento mecanoqu√≠mico sobre la muestra que facilitara el proceso de extracci√≥n posterior. Este pretratamiento se llev√≥ a cabo evaluando la influencia de diferentes reactivos s√≥lidos (Na2CO3, BaCO3, Li2CO3, CoCO3, K2CO3 y CaCO3) y se compar√≥ con la extracci√≥n convencional, as√≠ como con otras t√©cnicas novedosas en el campo de la extracci√≥n de compuestos bioactivos como el ultrasonidos y la irradiaci√≥n microondas. Este estudio demostr√≥ que el pretratamiento mecanoqu√≠mico permit√≠a obtener extractos con contenidos fen√≥licos comparables a los de la extracci√≥n convencional (75,54 GAE/g extracto), con la ventaja de que, para un mismo valor, el tiempo total de extracci√≥n se reduc√≠a m√°s de 10 veces mediante el uso de la mecanoqu√≠mica. Los compuestos principales identificados en el extracto fueron eugenol, metileugenol y elemicina. Aunque las extracciones asistidas por ultrasonidos y microondas resultaron en mayores rendimientos y valores m√°s altos en las propiedades de los extractos evaluadas que las realizadas con pretratamiento mecanoqu√≠mico, el presente estudio propone la sustituci√≥n de la extracci√≥n convencional por la mecanoqu√≠mica para obtener el mismo rendimiento, pero de una forma m√°s sostenible. La siguiente aproximaci√≥n que se abord√≥ para la valorizaci√≥n de los residuos de la poda de laurel fue su fraccionamiento para la obtenci√≥n una de las fracciones lignocelul√≥sicas presente y posterior conversi√≥n en compuestos de alto valor a√Īadido. As√≠, la Publicaci√≥n III versa sobre la extracci√≥n de polisac√°ridos (hemicelulosas y almid√≥n) de los residuos de la poda de laurel y su utilizaci√≥n como fuente de az√ļcares C5 y C6 para la s√≠ntesis de levulinato de metilo, mol√©cula de alto valor a√Īadido debido a que se trata de una mol√©cula plataforma para la s√≠ntesis de productos qu√≠micos relevantes como la ő≥- valerolactona. La fracci√≥n de polisac√°ridos se obtuvo por extracci√≥n hidrotermal (autohidr√≥lisis), determinando las condiciones √≥ptimas mediante un dise√Īo experimental en el que se contemplaron diferentes temperaturas (160, 180, 190 y 200 ¬įC) y tiempos (30, 45, 60 y 75 min). Todas las fracciones obtenidas se caracterizaron para conocer el perfil de carbohidratos, los √°cidos fen√≥licos, las prote√≠nas y la distribuci√≥n de pesos moleculares. Los polisac√°ridos obtenidos en las condiciones √≥ptimas (160 ¬įC 45 min) estaban compuestos de una mezcla de 37,87% de az√ļcares C5 y 60,86% de az√ļcares C6. Estos polisac√°ridos se utilizaron con √©xito para producir levulinato de metilo mediante la conversi√≥n simult√°nea de ambos tipos de az√ļcares bajo irradiaci√≥n microondas en un medio rico en metanol utilizando un catalizador simple y econ√≥mico como el Al2SO4. En este caso, se obtuvo un rendimiento √≥ptimo de levulinato de metilo del 40% a partir de polisac√°ridos purificados de residuos de la poda de laurel tras un proceso simple de extracci√≥n/purificaci√≥n de carbohidratos combinado con un paso catal√≠tico asistido por microondas. A pesar de que los polisac√°ridos vegetales principales de la pared celular son la celulosa y las hemicelulosas, los polisac√°ridos p√©cticos pueden representar hasta el 30% de la pared primaria. Estos polisac√°ridos p√©cticos han despertado gran inter√©s en los √ļltimos a√Īos para su aplicaci√≥n en √°reas como la cosm√©tica, la alimentaci√≥n, la farmacia y el envasado activo de alimentos. Por ello, la Publicaci√≥n IV estudia el aislamiento potencial de polisac√°ridos p√©cticos a partir de residuos de la poda de laurel y su aplicaci√≥n como aditivos en pel√≠culas para envasado activo de alimentos. La obtenci√≥n de estas pectinas se llev√≥ a cabo mediante extracci√≥n secuencial con agua subcr√≠tica, una tecnolog√≠a novedosa para la extracci√≥n de fracciones de polisac√°ridos con funcionalidades moleculares preservadas, utilizando diferentes combinaciones de tiempo (5, 10, 15 y 20 min) y temperatura (100, 120, 140 y 160 ¬įC). Los polisac√°ridos extra√≠dos estaban altamente enriquecidos en pectinas conservando su alto peso molecular (10-100 kDa), presentando adem√°s propiedades ideales para la citada aplicaci√≥n. Posteriormente, se prepararon pel√≠culas de quitosano enriquecidas con las pectinas, las cuales mejoraron las propiedades √≥pticas (‚Č•95% de capacidad de barrera a la luz-UV), antioxidantes (‚Č•95% de actividad de barrido de radicales) y la permeabilidad al vapor de agua, en comparaci√≥n con las pel√≠culas de quitosano puro. Adem√°s, la actividad antimicrobiana del quitosano se mantuvo en las pel√≠culas h√≠bridas. La adici√≥n del 10% de pectinas tambi√©n mejor√≥ las propiedades mec√°nicas, aumentando el m√≥dulo de Young en un 12% y la resistencia a la tensi√≥n en un 51%. As√≠, este trabajo demuestra la aplicaci√≥n de fracciones ricas en pectinas procedentes de residuos de la poda de laurel para su uso como aditivo en aplicaciones de envasado activo de alimentos, con triple acci√≥n como antioxidante, barrera y antimicrobiana. Por √ļltimo, la Publicaci√≥n V contenida en la presente Tesis Doctoral trata sobre el fraccionamiento, purificaci√≥n y aplicaci√≥n de la celulosa, la fracci√≥n polim√©rica m√°s abundante de los materiales lignocelul√≥sicos. As√≠, los residuos de la poda de laurel fueron empleados para la producci√≥n de micro/nanofibras de celulosa y su aplicaci√≥n como refuerzo en aerogeles de quitosano aplicables como almohadillas absorbentes para el envasado de alimentos. Las micro/nanofibras fueron obtenidas mediante homogeneizaci√≥n a alta presi√≥n, previo pretratamiento qu√≠mico de oxidaci√≥n mediada por TEMPO. Se obtuvieron dos clases de micro/nanofibras, con alto y bajo contenido en lignina residual, con el objetivo de estudiar tambi√©n el efecto de la lignina sobre la aplicaci√≥n deseada. Posteriormente, se caracterizaron las micro/nanofibras producidas y se prepararon los aerogeles. Como resultado, se obtuvieron aerogeles altamente porosos con propiedades mec√°nicas mejoradas gracias a la inclusi√≥n de las micro/nanofibras en su estructura, especialmente cuando √©stas se encontraban presentes al 5%. La ausencia de lignina en las micro/nanofibras condujo a una fuerte auto-asociaci√≥n aumentando este efecto refuerzo. Una vez encontrada la formulaci√≥n √≥ptima, se procedi√≥ a la fabricaci√≥n de los aerogeles bioactivos, conteniendo extracto de las hojas de laurel a distintas proporciones. Se observ√≥ que la presencia de lignina en las micro/nanofibras fue determinante en los perfiles de liberaci√≥n del extracto, encontr√°ndose que los aerogeles bioactivos que conten√≠an las micro/nanofibras con lignina liberaban el extracto m√°s r√°pidamente al medio que los que conten√≠an las micro/nanofibras libres de lignina, alcanzando en ambos casos una capacidad antioxidante m√°xima. Finalmente, el estudio de los aerogeles bioactivos como almohadillas absorbentes para la conservaci√≥n de carne, llevado a cabo en muestras de hamburguesas, mostr√≥ que estos materiales contribuyen a conservar el alimento durante 10 d√≠as como carne fresca cuando se formulan con ‚Č•2% de extracto. Adem√°s, la presencia de lignina residual en las fibras contribuy√≥ a este retraso en la oxidaci√≥n de la carne durante el almacenamiento.Due to the economic and environmental challenges facing society today, the member states of the United Nations proposed the 17 Sustainable Developments Goals (SDGs) in 2015. These goals focus on promoting ways of achieving sustainability in all possible areas (water, energy, climate, industries, economy, science, and technology). In this way, the need for society‚Äôs transition to the bioeconomy becomes imminent. Bioeconomy plays an important role in achieving the sustainable development since its main objective is that the current economy becomes based on the use of renewable resources and their conversion into high added-value products. The depletion of fossil resources, as well as fluctuating petroleum prices and environmental pollution problems, call for the search for a new perspective where the use of renewable resources is the basis. In this sense, biorefineries of lignocellulosic materials emerge as a brilliant solution. In biorefinery systems, different types of lignocellulosic residues are valorized to obtain useful, efficient, and valuable products that will help to achieve the much-desired sustainable development. Thus, this Doctoral Thesis has addressed different ways for the valorization of bay tree (Laurus nobilis L.) pruning waste from the biorefinery point of view, through its transformation, fractionation, and application in the preparation of new materials and high added-value products. Chemical modification of lignocellulosic residues by liquefaction reactions has emerged in recent years as a novel technique for the preparation of composite materials, acrylates and polyurethanes based on natural compounds. The polyols commonly used in the polyurethane industry are of petrochemical origin. Therefore, the preparation of natural polyols with similar characteristics to those derived from petroleum could open an alternative and sustainable path in the polyurethanes market. In this sense, Publication I of this Doctoral Thesis describes the synthesis of polyols from bay tree pruning residues, without previous fractionation process, and their application for the preparation of insulating polyurethane foams. The polyol obtained showed similar properties (number of hydroxyl groups, viscosity, and molecular weight) or even better than the polyols currently available on the market, in addition to reporting high liquefaction performance. Therefore, the polyol was perfectly applicable for the preparation of the foams. The insulating foams were prepared considering several parameters that usually influence the final structure of these materials: the type of diisocyanate used (MDI or TDI) and the addition of water as a physical blowing agent. According to the results obtained, the foams prepared with TDI showed an optimum formulation at an NCO/OH (RNCO/OH) molar ratio of 1.1 (40% wt. bay tree pruning polyol and without the addition of the blowing agent) in terms of bulk density and mechanical properties (compressive strength and Young's modulus). In the case of foams prepared with MDI, the optimum formulation was found to be RNCO/OH 0.63 (50% wt. bay tree pruning polyol and with the addition of the blowing agent). All formulated foams had a small and closed cell morphology and a higher thermal stability with the presence of the synthesized polyol. The results obtained in this study have allowed to suggest bay tree pruning waste polyol as a suitable substitute for the petroleum-based polyurethanes. On the other hand, traditionally, the best-known application of bay tree has been through its essential oil in cooking and pharmacy, despite having demonstrated good results in the treatment of diseases thanks to its antioxidant properties. These natural extracts are usually obtained by conventional Soxhlet extraction, which requires large volumes of extraction solvent as well as long extraction times. Going one step further, Publication II focuses on the optimization of obtaining natural extracts from bay leaves by environmentally friendly intensification methodologies. In this sense, a mechanochemical pretreatment protocol was established and applied on the sample to facilitate the subsequent extraction process. This pretreatment was carried out by evaluating the influence of different solid reagents (Na2CO3, BaCO3, Li2CO3, CoCO3, K2CO3 and CaCO3) and was compared with conventional extraction, as well as with other novel techniques in the field of bioactive compound extraction such as ultrasound and microwave irradiation. This study showed that mechanochemical pretreatment allowed obtaining extracts with phenolic contents comparable to those of conventional extraction (75.54 GAE/g extract), with the advantage that, for the same value, the total extraction time was reduced more than 10 times by using mechanochemistry. The main compounds identified in the extract were eugenol, methyleugenol and elemicin. Although ultrasound and microwave-assisted extractions resulted in higher yields and higher values in the properties of the extracts evaluated than those performed with mechanochemical pretreatment, the present study proposes the substitution of conventional extraction by mechanochemistry to obtain the same yield, but in a more sustainable way. The next approach for the valorization of bay tree pruning waste was its fractionation to obtain one of the lignocellulosic fractions present and its subsequent conversion into high value-added compounds. Thus, Publication III deals with the extraction of polysaccharides (hemicelluloses and starch) from bay tree pruning waste and their use as a source of C5 and C6 sugars for the synthesis of methyl levulinate, a high-value added molecule because it is an important platform molecule for the synthesis of relevant chemicals such as ő≥-valerolactone. The polysaccharide fraction was obtained by hydrothermal extraction (autohydrolysis), determining the optimum conditions by means of an experimental design in which different temperatures (160, 180, 190 and 200 ¬įC) and times (30, 45, 60 and 75 min) were considered. All the fractions obtained were characterized to determine the carbohydrate profile, phenolic acids, proteins, and molecular weight distributions. The polysaccharides obtained under the optimum conditions (160 ¬įC 45 min) were composed of a mixture of 37.87% C5 sugars and 60.86% C6 sugars. These polysaccharides were successfully used to produce methyl levulinate by simultaneous conversion of both types of sugars under microwave irradiation in a methanol-rich medium using a simple and inexpensive catalyst such as Al2SO4. In this case, an optimum methyl levulinate yield of 40% was obtained from polysaccharides purified from bay tree pruning waste after a simple carbohydrate extraction/purification process combined with a microwave-assisted catalytic step. Although the main plant polysaccharides of the cell wall are cellulose and hemicelluloses, pectic polysaccharides can represent up to 30% of the primary wall. These pectic polysaccharides have attracted great interest in recent years for their application in areas such as cosmetics, food, pharmaceuticals, and active food packaging. Therefore, Publication IV studies the potential isolation of pectic polysaccharides from bay tree pruning waste and their application as additives in films for active food packaging. These pectins were obtained by sequential subcritical water extraction, a novel technology for the extraction of polysaccharide fractions with preserved molecular functionalities, using different combinations of time (5, 10, 15 and 20 min) and temperature (100, 120, 140 and 160 ¬įC). The extracted polysaccharides were highly enriched in pectins preserving their high molecular weight (10-100 kDa), also presenting ideal properties for the mentioned application. Subsequently, chitosan films enriched with the pectins were prepared, which improved the optical properties (‚Č•95% light-UV barrier capacity), antioxidant capacity (‚Č•95% radical scavenging activity) and water vapor permeability compared to pure chitosan films. Moreover, the antimicrobial activity of chitosan was maintained in the hybrid films. The addition of 10% pectins also improved the mechanical properties, increasing Young's modulus by 12% and tensile strength by 51%. Thus, this work demonstrates the application of pectin-rich fractions from bay tree pruning waste as an additive in active food packaging applications, with triple action as antioxidant, barrier and antimicrobial. Finally, Publication V contained in this Doctoral Thesis deals with the fractionation, purification, and application of cellulose, the most abundant polymeric fraction of lignocellulosic materials. Thus, bay tree pruning waste was used for the production of cellulose micro/nanofibers and their application as reinforcement in chitosan aerogels applicable as absorbent pads for food packaging. The micro/nanofibers were obtained by high-pressure homogenization, prior TEMPO-mediated oxidation as chemical pretreatment. Two kinds of micro/nanofibers were obtained, with high and low residual lignin content, in order to study also the effect of lignin on the desired application. Subsequently, the produced micro/nanofibers were characterized, and aerogels were prepared. As a result, highly porous aerogels with improved mechanical properties were obtained due to the inclusion of micro/nanofibers in their structure, especially when these were present at 5%. The absence of lignin in the micro/nanofibers led to a strong self-association enhancing this reinforcing effect. Once the optimal formulation was found, the bioactive aerogels were fabricated, containing the bay leaf extract at different proportions. It was observed that the presence of lignin in the micro/nanofibers was determinant in the release profiles of the extract, finding that the bioactive aerogels containing the micro/nanofibers with lignin released the extract more rapidly to the medium than those containing the lignin-free micro/nanofibers, reaching in both cases a maximum antioxidant capacity. Finally, the study of bioactive aerogels as absorbent pads for meat preservation in burger samples showed that these materials contribute to preserve the food for 10 days as fresh meat when formulated with ‚Č•2% extract.

    Nutritional composition and bioactive compounds of mini watermelon genotypes in Bangladesh

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    Given the present rising trends in changing lifestyle and consumption patterns, watermelon production has shifted from big to small-sized fruits having desirable quality attributes. Hence, analyses of fruit quality traits of mini watermelon are crucial to develop improved cultivars with enhanced nutritional compositions, consumer-preferred traits and extended storage life. In this context, fruit morphological and nutritional attributes of five mini watermelon genotypes namely BARI watermelon 1 (W1), BARI watermelon 2 (W2), L-32468 (W3), L-32236 (W4) and L-32394 (W5) were evaluated to appraise promising genotypes with better fruit quality. The evaluated genotypes expressed different levels of diversity for fruit physical qualitative traits including differences in shape, rind and flesh color and texture. The study also revealed significant variability among the genotypes regarding all observed fruit morphological and nutritional aspects as well as bioactive compounds. Among the studied genotypes, W1 stood out with the highest TSS as well as rind vitamin C and total phenolic content accompanied by higher fruit weight and thick rind. On the other hand, W3 genotype was featured with higher amount of \b{eta} carotene, total phenolic and flavonoid content in its flesh along with rind enriched with \b{eta} carotene and minerals. However, comparatively higher amount of sugar and total flavonoid content was recorded in the rind of W5 genotype. Therefore, W1 and W3 could be exploited for table purpose and using in breeding program to develop mini watermelon cultivars with more attractive fruits in terms of quality acceptance and nutritional value in Bangladesh. Furthermore, rind of BARI watermelon 1 and L-32394 could be considered as the potential cheap source of bioactive compounds to be used for dietary and industrial purpose which would decrease the solid waste in the environment.Comment: 22 pages, 6 tables, 3 figure

    Agronomic Performance and Nutraceutical Quality of a Tomato Germplasm Line Selected under Organic Production System

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    Organic tomato production is increasing worldwide, thus making necessary the development of varieties adapted to this farming system. It is now well known that the implementation of local tomato plant breeding programs for organic farming is required to increase the performance of varieties in this typology of cultivation regime. In this research, the agronomic performance, nutraceutical contents, and radical scavenging activity of a tomato germplasm line (OSTGL), selected under organically grown conditions, were evaluated for two consecutive years (2018 and 2019) in comparison with the variety ‚ÄėRio Grande‚Äô, frequently grown organically in Tunisia. Carotenoids, phenolics, vitamin C, and radical scavenging capacity were assayed spectrophotometrically, while tocopherols were analyzed by HPLC. All data were not affected by year-to-year variability. The OSTGL line showed significantly higher marketable yield, total phenol, flavonoid, vitamin C, őĪ-tocopherol and ő≥-tocopherol contents, along with radical scavenging activity. The OSTGL red-ripe berries also showed comparable values for average weight, soluble solids, pH, titratable acidity, firmness and coloration, as well as lycopene and ő≤-carotene contents. This open pollinated tomato germplasm line demonstrated to be an effective sustainable variety for improving fruit yield, agronomic, and nutraceutical characteristics under an organic management system
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