23 research outputs found

    Volatile Components of Strawberries

    Get PDF
    Strawberries of such cultivars as “Ducat”, “Honey” and “Polka” were studied to define the content of aromatic volatiles using the methods of highly efficient liquid chromatography. About 49 components were identified in the composition of volatiles of ripe strawberries, namely esters, aldehydes, ketones, furanone, organic acids, aroma compounds, lactones, terpenic compounds, and alkanes. Their shares are the following: esters—12.8–41.8%, aldehydes—5.9–15.9%, ketones—8.7–35.6%, furanone—22.7–24.4%, and organic acids—2.47–21.85%. Depending on a cultivar, typical volatile components of strawberries are ethyl butanoate (10.1–30.65%), trans-2-hexenal (5.31–15.55%), acetoin (8.20–35.67), 2.5–dimethyl-4-methoxy-3(2H)-furanone (mesifurane) (19.08–19.92%) and 2.5-dimethyl-4-hydroxy-3(2H)-furanone (3.43–4.40%). A peculiar feature of volatile compounds of Polka strawberries is the highest ester share—41.77% of total content of volatiles, for Ducat strawberries it would be the share of ketones (35.88%), and for Honey strawberries—γ-decalaktone (12.41%). A high aroma activity of ripe strawberries is recorded on 2.5-dimethyl-4-methoxy-3(2H)-furanone (mesifurane) and 2.5-dimethyl-4-hydroxy-3(2H)-furanone (furaneol). Sweet, caramel flavors are typical for strawberries of the studied cultivars. Strawberries of Polka cultivar have a pronounced aroma

    Aroma characterisation and retention after heat treatment and drying of fruits using extraction and GC-MS analysis

    Get PDF
    This study concerns the identification and characterisation of volatile components of fruits, and evaluation of the effect of heat treatment and drying on retention or loss of volatiles of fruits. The investigation included developing a procedure to extract volatile components from the fruit matrix, a purification step, separation, identification and quantification. Initial experiments with Vangueria infausta L. showed that some components, especially sugars, degrade during heating in the GC analysis, producing furfural, hydroxyl methyl furfural (HMF) and other volatiles. These compounds are obtained together with the native aroma components of the fruit, making analysis difficult. We developed a procedure using a hydrophobic column that could retain the hydrophobic aroma components and eliminate sugars that could disrupt the analyses. The extract was analysed by GC. The volatile components found in pulp of Vangueria infausta were primarily hexanoic acid, octanoic acid, ethyl hexanoate, ethyl octanoate, methyl hexanoate and methyl octanoate. Based on the odour activity values, it could be concluded that the odour of the fruit is mainly attributed to ethyl hexanoate and ethyl octanoate (paper I). Drying is often used to process and preserve food stuff but many food attributes including aromas which are important for palatability and consumer interest are affected by the process. Our research showed that the principal aroma components are well preserved during the initial phase of drying (down to about a relative water activity of 0.65). However the aromas are lost after more extensive drying. A possible explanation for volatilisation is the sugar crystallisation that occurs below a RH of around 0.70. (paper II). Also we evaluated the effects of drying with or without blanching on volatiles of mango (Mangifera indica L.). Fresh, blanched and dried mango samples were analysed (paper III). The fresh sample presented a very large number of peaks. The blanching was carried out in water and microwave at 70°C during 10 minutes and at 90°C during 2 minutes. Blanching increased the levels of aroma components. Both blanching procedures had no dramatic effect on the impact of the blanching. Prolonged hot air drying (aw=0.65) reduced most of the aroma. α-pinene vi and 1-butanol were strongly affected due their volatility. Drying had no great effect on components with high boiling points, which displayed significant retention even after extensive dehydration. Ethyl butanoate was high retained despite its high volatility. To evaluate a possible influence of sugar crystallisation on aroma retention a further study involved three model matrixes based on carbohydrates aqueous solution plus oils: I) pectin-sucrose-oils, II) pectinmicrocrystalline cellulose-sucrose-oils and III) microcrystalline cellulosesucrose- oils. The oil phase comprised the reference materials of the most powerful aroma components found in Vangueria infausta (hexanoic acid, ethyl hexanoate and ethyl octanoate). The model mixture was dried at 80°C, 3 m/s for 60-420 min prior to GC analysis (Paper IV). The aroma components were preserved in all models throughout the drying process (until aw ≈0.8). So sugar crystallisation did not induce the loss of volatiles. However noticeable sugar crystallisation was observed in model II. We assume that the presence of pectin and microcrystalline cellulose increased the ability of the matrix to compact, as water activity decreased during drying. So sugar crystallisation is probably the reason for aroma retention within the matrix. The results of the studies in this thesis illustrate what happens to volatiles during thermal processing of fruits. These results could help design a better strategy for aroma isolation and characterisation, and explain the aroma entrapment due to sugar crystallisation during drying of fruits. The results can also be used to design a strategy for sustainable utilisation of volatile components of fruits like Vangueria infausta, one of the wild fruits to be included in a formulation of new industrial food products. However, more studies are needed in order to learn more about sustainable utilisation of various wild fruits growing in Mozambique and southern Africa

    Smell of Heritage

    Get PDF
    We don’t know much about the smells of the past. Yet, odours play an important role in our daily lives: they affect us emotionally, psychologically and physically, and influence the way we engage with history. Can this lead us to consider certain smells as cultural heritage? And if so, what would be the processes for the identification, protection and conservation of those heritage smells? In order to answer these questions, the connection between olfaction and heritage was approached through the framework of Significance Assessment – Chemical Analysis – Sensory Analysis – Archiving. Four case studies were developed, each around a different smell: old books and historic libraries; scented conservation wax, historic pot-pourri, and mould. Through them, the validity of the framework was tested, while exploring associated aspects of olfaction in heritage: authenticity, value in connection with visitor experience and interpretation, considerations around historic odour reconstruction and role of non-sensory input in historic odour perception. Odour characterisation was achieved by chemical analysis of the volatile organic compounds (VOC) for each case study, using either HS-SPME-GS-MS or HS-TD-GC-TOF-MS. Sensory characterisation was obtained via GC-O and odour evaluation panels. Visitor experience surveys were also conducted in a historic house setting. Smells were documented using odour wheels and other forms of visual representation. Some findings of this study worth discussing are: (1) the perception of authenticity in historic odours is not necessarily linked to a chemically-accurate reconstruction; (2) several historic odours present an ambiguity that lead to characterisation being significally modulated by both sensory and non-sensory information and (3) there is a great potential for non-visual engagement of visitors with the space and collections in heritage institutions, currently untapped. This is the first systematic study of olfaction in heritage and therefore its insights will be relevant to the heritage community, as well as engaging with current research in the field of odour perception, interpretation and representation

    Storage of halved strawberry fruits affects aroma, phytochemical content and gene expression, and is affected by pre-harvest factors

    Get PDF
    Introduction: Strawberry fruit are highly valued for their aroma which develops during ripening. However, they have a short shelf-life. Low temperature storage is routinely used to extend shelf-life for transport and storage in the supply chain, however cold storage can also affect fruit aroma. Some fruit continue to ripen during chilled storage; however, strawberries are a non-climacteric fruit and hence ripening postharvest is limited. Although most strawberry fruit is sold whole, halved fruit is also used in ready to eat fresh fruit salads which are of increasing consumer demand and pose additional challenges to fresh fruit storage. Methods: To better understand the effects of cold storage, volatilomic and transcriptomic analyses were applied to halved Fragaria x ananassa cv. Elsanta fruit stored at 4 or 8°C for up to 12 days over two growing seasons. Results and discussion: The volatile organic compound (VOC) profile differed between 4 or 8°C on most days of storage. Major differences were detected between the two different years of harvest indicating that aroma change at harvest and during storage is highly dependent on environmental factors during growth. The major component of the aroma profile in both years was esters. Over 3000 genes changed in expression over 5 days of storage at 8°C in transcriptome analysis. Overall, phenylpropanoid metabolism, which may also affect VOCs, and starch metabolism were the most significantly affected pathways. Genes involved in autophagy were also differentially expressed. Expression of genes from 43 different transcription factor (TF) families changed in expression: mostly they were down-regulated but NAC and WRKY family genes were mainly up-regulated. Given the high ester representation amongst VOCs, the down-regulation of an alcohol acyl transferase (AAT) during storage is significant. A total of 113 differentially expressed genes were co-regulated with the AAT gene, including seven TFs. These may be potential AAT regulators

    Impact of Beneficial Microorganisms on Strawberry Growth, Fruit Production, Nutritional Quality, and Volatilome

    Get PDF
    Arbuscular mycorrhizal fungi (AMF) colonize the roots of most terrestrial plant species, improving plant growth, nutrient uptake and biotic/abiotic stress resistance and tolerance. Similarly, plant growth promoting bacteria (PGPB) enhance plant fitness and production. In this study, three different AMF (Funneliformis mosseae, Septoglomus viscosum, and Rhizophagus irregularis) were used in combination with three different strains of Pseudomonas sp. (19Fv1t, 5Vm1K and Pf4) to inoculate plantlets of Fragaria × ananassa var. Eliana F1. The effects of the different fungus/bacterium combinations were assessed on plant growth parameters, fruit production and quality, including health-promoting compounds. Inoculated and uninoculated plants were maintained in a greenhouse for 4 months and irrigated with a nutrient solution at two different phosphate levels. The number of flowers and fruits were recorded weekly. At harvest, fresh and dry weights of roots and shoots, mycorrhizal colonization and concentration of leaf photosynthetic pigments were measured in each plant. The following fruit parameters were recorded: pH, titratable acids, concentration of organic acids, soluble sugars, ascorbic acids, and anthocyanidins; volatile and elemental composition were also evaluated. Data were statistically analyzed by ANOVA and PCA/PCA-DA. Mycorrhizal colonization was higher in plants inoculated with R. irregularis, followed by F. mosseae and S. viscosum. In general, AMF mostly affected the parameters associated with the vegetative portion of the plant, while PGPB were especially relevant for fruit yield and quality. The plant physiological status was differentially affected by inoculations, resulting in enhanced root and shoot biomass. Inoculation with Pf4 bacterial strain increased flower and fruit production per plant and malic acid content in fruits, while decreased the pH value, regardless of the used fungus. Inoculations affected fruit nutritional quality, increasing sugar and anthocyanin concentrations, and modulated pH, malic acid, volatile compounds and elements. In the present study, we show for the first time that strawberry fruit concentration of some elements and/or volatiles can be affected by the presence of specific beneficial soil microorganisms. In addition, our results indicated that it is possible to select the best plant-microorganism combination for field applications, and improving fruit production and quality, also in terms of health promoting properties

    Non-destructive Detection of Food Adulteration to Guarantee Human Health and Safety

    Get PDF
    The primary objective of this review is to critique the basic concepts of non-destructive detection of food adulteration and fraud which collectively represent a tremendous annual financial loss worldwide and a major cause of human disease. The review covers the principles of the analytical instrumentation used for the non-destructive detection of food adulteration. Examples of practical applications of these methods for the control of food adulteration are provided and a comparative analysis of the advantages and disadvantages of instrumental methods in food technology are critiqued.Целью данного обзора является критическое рассмотрение основных понятий неразрушающего выявления фальсификации и подделки продуктов питания, которые в целом вызывают огромные ежегодные финансовые убытки во всем мире и являются одной из основных причин заболеваний человечества. Материалы и методы. Литература, указанная в данном обзоре, была получена в результате поиска библиографической информации в CAB abstracts, AGRICOLA, SciFinder Scholar, Modern Language Association (MLA), American Psychological Association (APA), OECD / EEA database по инструментам, которые используются для экологической политики и управления природными ресурсами, и Web of Science.Результаты и обсуждение. Фальсификация пищевых продуктов означает преднамеренное, обманное добавление посторонних, нестандартных или дешевых ингредиентов в продукты, или разбавление или удаление некоторых ценных ингредиентов с целью увеличения прибыли. В современных условиях производители стремятся увеличить выпуск своей продукции зачастую путем изготовления и продажи некачественных и фальсифицированных продуктов.“Неразрушающее выявление фальсификации пищевых продуктов” означает анализ образца и его существенных признаков без изменения физических и химических свойств образца. Повышение качества и безопасности пищевых продуктов путем разработки научных методов обнаружения фальсификации является главным условием для поддержания здоровья потребителей. Точная объективная оценка качества и выявление фальсификации пищевых продуктов представляется важнейшей целью пищевой промышленности. В связи с совершенствованием технологии фальсификации продуктов важно быть в курсе современных, самых точных методов контроля их фальсификации. С этой целью данный обзор рассматривает основные понятия выявления фальсификации продуктов питания, принципы устройств и возможные практические применения современных методов неразрушающего выявления фальсификации продуктов питания; сравнительный анализ преимуществ и недостатков инструментальных методов, используемых в пищевых технологиях. Каждый из рассмотренных методов обсуждается с точки зрения возможных различных консистенций продуктов – газов (свободного пространства вокруг продукта), свободно текущих жидкостей (соков), мутных и вязких жидкостей (меда как продукта растительного происхождения, растительных масел) и интактных продуктов (фруктов и овощей).Выводы. Результаты, освещенные в обзоре, рекомендуется использовать при контроле качества и безопасности пищевых продуктов.Метою даного огляду є критичний розгляд основних понять неруйнівного виявлення фальсифікації і підробки продуктів харчування, які в цілому викликають величезні щорічні фінансові збитки у всьому світі і є однією з основних причин захворювань людства. Матеріали і методи. Література, зазначена в даному огляді, була отримана в результаті пошуку бібліографічної інформації в in CAB abstracts, AGRICOLA, SciFinder Scholar, Modern Language Association (MLA), American Psychological Association (APA), OECD/EEA database щодо інструментів, які використовуються для екологічної політики та управління природними ресурсами, та Web of Science. Результати та обговорення. Фальсифікація харчових продуктів означає умисне, облудне додавання сторонніх, нестандартних або дешевих інгредієнтів в продукти, або розбавлення чи видалення деяких цінних інгредієнтів з метою збільшення прибутків. У сучасних умовах виробники прагнуть збільшити випуск своєї продукції найчастіше шляхом виготовлення та продажу неякісних та фальсифікованих продуктів. “Неруйнівне виявлення фальсифікації харчових продуктів” означає аналіз зразка і його істотних ознак без зміни фізичних і хімічних властивостей зразка. Підвищення якості та безпеки харчових продуктів шляхом розробки наукових методів виявлення фальсифікації є головною умовою для підтримки здоров’я споживачів. Точна об’єктивна оцінка якості і виявлення фальсифікації харчових продуктів представляється найважливішою метою харчової промисловості. У зв’язку з удосконаленням технології фальсифікації продуктів важливо бути в курсі сучасних, найбільш точних методів контролю їх фальсифікації. З цією метою даний огляд розглядає основні поняття виявлення фальсифікації продуктів харчування, принципи пристроїв і можливі практичні застосування сучасних методів неруйнівного виявлення фальсифікації продуктів харчування; порівняльний аналіз переваг і недоліків інструментальних методів, що застосовуються в харчових технологіях. Кожен з розглянутих методів обговорюється з точки зору можливих різних консистенцій продуктів - газів (вільного простору навколо продукту), вільно текучих рідин (соків), каламутних та в'язких рідин (меду як продукту рослинного походження, рослинних масел) і інтактних продуктів (фруктів і овочів). Висновки. Результати, висвітлені в огляді, рекомендується використовувати під час контролю якості та безпеки харчових продуктів

    Olfaction As The Paradigm For Perceptual Philosophy

    Full text link
    Plato wrote that smell is of a half-formed nature and that not much can be said about it, and Kant identified smell as the most ungrateful and most dispensable of the senses. Because contemporary philosophers share this distaste for smell perception, olfaction is often dismissed or ignored in philosophical accounts of perception. Instead, contemporary philosophy of perception is based almost exclusively on visual perception. The goal of this dissertation is to show that this focus on a single modality distorts our understanding of what perception is. I am not the first to realize the potential of opening up perceptual philosophy to the non-visual modalities. Bill Lycan asked how the philosophy of perception would be different if smell had been taken as a paradigm rather than vision. (Lycan 2000). In this dissertation, I will try to answer this question. My analysis will show that philosophy of perception would be very different, were it based on olfaction. Many of the most basic concepts of philosophy of perception are based on peculiarities of visual perception that do not generalize to other modalities

    Genetic engineering of plant volatiles in fleshy fruits: pest repellency and disease resistance through D-limonene downregulation in transgenic orange plants

    Full text link
    Los terpenos constituyen el mayor grupo de metabolitos secundarios, siendo componentes de las glándulas de aceites esenciales, de las flores y de las resinas defensivas de plantas aromáticas, a los que proporcionan sus aromas y sabores característicos. Los terpenos volátiles se asocian a la defensa de muchas especies de plantas, animales y microorganismos contra depredadores, patógenos y competidores. Por otra parte, estos compuestos parecen servir como señales para atraer a los polinizadores y agentes dispersores de semillas, así como a depredadores de plagas. El estudio de compuestos orgánicos volátiles emitidos durante el desarrollo del fruto y después del desafío con diferentes agentes bióticos puede ayudar a conocer las interacciones de los frutos carnosos no sólo con vertebrados dispersores y depredadores, sino también con insectos y microorganismos. Los frutos carnosos son particularmente ricos en volátiles. En los frutos cítricos, los monoterpenos son los principales componentes de las glándulas del aceite esencial de la cáscara (flavedo), siendo el D-limoneno el más abundante (hasta 95% en la naranja). Esta característica hace que los cítricos sean un buen sistema modelo para el estudio de la función de los terpenos en los frutos. La biología molecular moderna permite la realización de experimentos para comprobar la función de terpenos por medio del uso de organismos transformados genéticamente en los que se han manipulado los niveles de acumulación de dichos compuestos. En este trabajo, se ha utilizado un plásmido que alberga el cDNA completo del gen de una limoneno sintasa de cítricos (CiTMTSE1) en orientación antisentido (AS) o sentido (S) para modificar la expresión y la acumulación de D-limoneno en plantas de naranjo dulce (Citrus sinensis L. Osb.). La acumulación de D-limoneno en las frutas AS se redujo drásticamente pero la acumulación de otros terpenos también se modificó, afectando a compuestos tales como alcoholes monoterpenos, cuya concentración se incrementó en la cáscara de las frutas. Las plantas transformadas fueron morfológicamente indistinguibles de las plantas control (WT) y de las plantas transformadas con el vector vacío (EV). Los frutos transgénicos fueron desafiados con un insecto plaga y con diferentes patógenos para probar si la alteración de los niveles de acumulación de estos volátiles daba como resultado una mejora en la respuesta del flavedo frente a plagas y patógenos. Los machos de la mosca mediterránea de la fruta (Ceratitis capitata) expuestos a las frutas AS y EV en ensayos en túnel de viento fueron significativamente más atraídos por el aroma de los frutos control EV. En otros experimentos de desafío con el hongo de la podredumbre verde Penicillium digitatum y la bacteria causante de la cancrosis de los cítricos Xanthomonas axonopodis subsp. citri, las frutas transgénicas con un contenido reducido de D-limoneno mostraron elevada resistencia a estos patógenos. El alto contenido en D-limoneno en la cáscara de naranjas maduras puede ser una señal para la atracción de plagas y microorganismos que podrían estar involucrados en la facilitación del acceso a la pulpa de los frugívoros dispersores de semillas. El análisis de la expresión génica global en el flavedo de las frutas transgénicas vinculó la disminución de D-limoneno y la reducción de la expresión de genes del metabolismo de monoterpenos con la activación de la expresión de genes implicados en inmunidad innata, incluyendo factores de transcripción, genes de quinasas implicadas en la entrada de Ca2+ en la célula y genes implicados en la activación de las cascadas de MAPKs, con la consiguiente activación de la ruta de señalización de ácido jasmónico (JA), lo que provocó la activación del metabolismo de JA y un aumentó drástico de la acumulación de JA en la cáscara de la naranja tras el desafío con P. digitatum, lo que explicaría la resistencia al menos a hongos necrotrofos observada en las frutas. Estos resultados indican que la acumulación de D-limoneno en la cáscara de la naranja estaría implicada en la interacción trófica entre las frutas, insectos y microorganismos, lo cual proporciona una visión mucho más amplia de las funciones de los terpenos en la naturaleza. También representa una alternativa muy prometedora para incrementar la resistencia o tolerancia de las plantas frente a patógenos y plagas.Terpenes, the largest group of secondary metabolites, are well known as constituents of essential oils, floral scents and defensive resins of aromatic plants, to which they impart their characteristic aromas and flavors. Terpene volatiles defend many species of plants, animals and microorganisms against predators, pathogens and competitors. Moreover, those compounds seem to serve as advertisements to attract pollinators and seed-dispersal agents as well as pest predators. The study of VOCs emitted during fruit development and after challenge with different biotic agents may help to determine the interactions of fleshy fruits not only with legitimate vertebrate dispersers and predators, but also with insects and microorganisms. Fleshy fruits are particularly rich in volatiles. In citrus fruits, monoterpenes are the main components of the essential oil glands of the peel, being D-limonene the most abundant one (up to 95% in orange fruits). This characteristic makes citrus a good model system for studying the function of terpenes in plants. Modern molecular biology now enable experiments to test terpenoid function by the use of genetically transformed organisms in which terpene levels have been manipulated. In this work, a plasmid harboring the complete cDNA of a citrus limonene synthase gene (CiTMTSE1) in antisense (AS) or sense (S) orientation was used to modify the expression and accumulation of D-limonene of sweet orange (Citrus sinensis L. Osb) plants. D-limonene accumulation in AS fruits was dramatically reduced but the accumulation of other terpenoids was also modified, such as monoterpene alcohols, whose concentration increased in the peel of fruits. Genetically transformed plants were morphologically indistinguishable from wild-type (WT) and empty vector (EV) control plants. Transgenic fruits were challenged against a pest and different pathogens to test whether volatile profile alteration results in an improvement in the response of the fruit flavedo against them. Males of the Mediterranean fruit fly (Ceratitis capitata) exposed to AS fruits versus EV in wind tunnel assays were significantly more attracted to the odor of EV control fruits. In separate experiments with the green mould rot of citrus fruits and citrus canker caused by Penicillium digitatum and Xanthomonas axonopodis subsp. citri, respectively, transgenic fruits with a reduced content in D-limonene showed resistance to both pathogens. High D-limonene content in mature orange peels may be a signal for attractiveness of pests and microorganisms which might be likely involved in facilitating the access to the pulp of seed dispersal frugivores. A global gene expression analysis of the flavedo of AS transgenic fruits linked the decrease of D-limonene and monoterpene metabolism to the up-regulation of genes involved in the innate immunity response, including transcription factors together with Ca2+ entry into the cell and activation of MAPK cascades, contributing to activation of jasmonic acid (JA) signaling, which triggered the up-regulation of JA metabolism and drastically increased the accumulation of JA in orange peels upon fungal challenge, explaining the resistance to necrotrophic fungi observed in AS fruits. These results indicate that limonene accumulation in the peel of citrus fruit appears to be involved in the successful trophic interaction between fruits, insects, and microorganisms and provide a much more comprehensive view of roles of terpenes in nature. It also represents a very promising alternative for increasing resistance or tolerance of plants to pathogens.Rodríguez Baixauli, AM. (2013). Genetic engineering of plant volatiles in fleshy fruits: pest repellency and disease resistance through D-limonene downregulation in transgenic orange plants [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/31655TESI
    corecore