Uso de procesos convencionales e innovadores para la valorización de los subproductos de la horchata

La “Horchata de chufa" o más comúnmente conocida como “Horchata” es una bebida tradicional, no alcohólica, dulce y de aspecto blanquecino obtenida a partir de tubérculos de chufa (Cyperus esculentus L. var. Sativus Boeck) consumida fundamentalmente en la Comunidad Valenciana durante la época de verano, aunque en los últimos años ha experimentado un crecimiento en su consumo tanto a nivel español como en el resto del mundo. Durante el proceso de elaboración de la “Horchata” se producen una gran cantidad de residuos y subproductos tanto sólidos como líquidos, donde los sólidos pueden representar hasta el 60% del material vegetal. Estos subproductos se han considerado tradicionalmente como desechos industriales sin valor comercial y se han utilizado fundamentalmente como pienso para animales. Los subproductos líquidos destacan por su alto contenido en prebióticos, antioxidantes y como sustituto del agua en productos cárnicos. Por otra parte, los subproductos sólidos pueden ser utilizados para diferentes usos, debido a su alto contenido en fibra dietética, compuestos antioxidantes bioactivos, además de tener buenas propiedades tecnológicas (capacidad de retención de agua, capacidad de emulsión y estabilidad de emulsión). El objetivo de la presente Tesis Doctoral es la recuperación caracterización de diversos nutrientes y compuestos bioactivos obtenidos a partir de subproductos sólidos del proceso de elaboración de la “horchata”. Fundamentalmente, el estudio se ha centrado en la extracción de aceite y evaluación del contenido graso y perfil de ácidos así como vitamina E del mismo. También se ha evaluado el contenido de compuestos antioxidantes bioactivos, capacidad antioxidante total y parámetros fisicoquímicos de los extractos obtenidos. Para obtener los extractos, se utilizaron diferentes técnicas de extracción, tanto métodos convencionales (ej. extracción convencional sólido/líquido, Soxhlet, etc.) como procesos innovadores (ej. fluidos supercríticos (SC-CO₂)), también conocidos como “extracción verde”. Posteriormente, los extractos se analizaron mediante la utilización de diferentes técnicas analíticas, como espectrofotometría y métodos cromatográficos como por ejemplo cromatografía de gases con detector de ionización de llama, cromatografía líquida acoplada a espectrometría de masas en tándem, etc. También se revisó en la literatura disponible el potencial uso de otros procesos innovadores como ultrasonidos, pulsos eléctricos, altas presiones, solas y/o en combinación con enzimas, expresión mecánica asistida por gas, microondas, los cuales también se han mostrado interesantes de cara a la valorización de los subproductos obtenidos durante la elaboración de la “Horchata”. Tras evaluar los resultados obtenidos, se observó cómo los subproductos de la "horchata" presentan un contenido importante de aceite, y compuestos antioxidantes bioactivos, aunque es necesario seleccionar el método de extracción apropiado para conseguir recuperar estos compuestos de la manera adecuada. Se observó que el contenido de nutrientes y compuestos antioxidantes bioactivos difiere de acuerdo al método de extracción utilizado. Por ejemplo, tras utilizar la extracción con fluidos supercríticos, se observó un aumento en la extracción de aceite tras aumentar la presión utilizada, aunque el rendimiento fue inferior al obtenido tras utilizar extracción convencional mediante el método Folch o Soxhlet. Eso sí, en el caso de los fluidos supercríticos se evitó la utilización de disolventes tóxicos. Asimismo, el aceite extraído presentó una mayor estabilidad oxidativa tras aplicar SC-CO2 a 30 y 40 MPa, en comparación con las extracciones realizadas a presiones más bajas o al procedimiento de extracción convencional. La extracción con SC-CO2 fue más eficiente para recuperar compuestos fenólicos lipofílicos con alta capacidad antioxidante en comparación con el procedimiento convencional de extracción (método Folch). Se observó una mayor extracción de los diferentes compuestos individuales, identificados y cuantificados por cromatografía líquida acoplada a espectrometría de masas en tándem cuando se aumentó la presión de tratamiento obteniendo los valores más altos cuando la presión fue de 40 MPa. Por otro lado, también se observó que tras utilizar la extracción convencional sólido/líquido, modificando el tiempo y la temperatura de extracción así como el disolvente utilizado, la eficiencia de extracción de los compuestos fenólicos totales fue mayor al aumentar la temperatura. Asimismo, concentraciones más altas de etanol y tiempos de extracción prolongados también promovieron una mejora en la extracción de estos compuestos. La capacidad antioxidante también aumentó cuando se utilizaron mayores concentraciones de etanol, con un mayor tiempo de extracción y a mayor temperatura. Estos resultados se podrían traducir en beneficios económicos derivados de la valorización de los subproductos frente a su eliminación con el fin de preservar el medio ambiente de residuos procedentes de la industria horchatera de una manera sostenible, reduciendo la huella de dióxido de carbono y proteger la salud del consumidor mediante la prevención o reducción de los impactos globales del uso de los recursos y la mejora de la eficacia de dicho uso."Horchata de chufa" or more commonly known as "Horchata" is a traditional, non-alcoholic, sweet and whitish-looking drink obtained from tubers of tiger nut (Cyperus esculentus L. Sativus Boeck), consumed mainly in the Valencian Community during the summer season, although over the last years it has experienced a growth in its consumption both in Spain and in the rest of the world. During "Horchata" production process, a large amount of wastes and by-products are produced, both solid and liquids, where solid ones can represent up to 60% of the plant material. These by-products have been traditionally considered as industrial waste without commercial value and have been used mainly as animal feed. The liquid by-products stand out for their high content in prebiotics, antioxidants and as a substitute for water in meat products. On the other hand, solid by-products an be used for different applications, due to their high content of dietary fiber, antioxidant bioactive compounds, in addition to having good technological properties (water retention capacity, emulsion capacity and emulsion stability, among others). The aim of the present PhD Thesis is the recovery and characterization of nutrients and antioxidant bioactive compounds obtained from "Horchata" solid by-products. The study has been mainly focused on the extraction of oil and the evaluation of its fatty acid content and profile as well as vitamin E amount. The content of antioxidant bioactive compounds, total antioxidant capacity and physicochemical parameters of the obtained extracts have been also evaluated. To obtain the extracts, different extraction techniques were used, both conventional methods (eg conventional solid/liquid extraction, Soxhlet, etc.) and innovative processes (eg. supercritical fluids (SC-CO₂)), also known as "green extraction". Subsequently, the extracts were analyzed using different analytical techniques, such as spectrophotometry and chromatographic methods such as gas chromatography with flame ionization detector, liquid chromatography coupled to tandem mass spectrometry, etc. The potential use of other innovative processes such as ultrasounds, electric pulses, high pressures, alone and/or in combination with enzymes, gas-assisted mechanical expression, microwaves, which are also promising tools for the valorization of the by-products obtained during the elaboration of the "Horchata". After evaluating the results obtained, it was observed how "Horchata" by-products present an important content of oil, and antioxidant bioactive compounds, although it is necessary to select the appropriate extraction method in order to recover these compounds in the proper way. It was observed that the content of nutrients and antioxidant bioactive compounds differs according to the extraction method used. For example, after using extraction with supercritical fluids, an increase in the oil extraction was observed after increasing the pressure used, although the yield was lower than that obtained after using conventional extraction using the Folch or Soxhlet method. Of course, in the case of supercritical fluids the use of toxic solvents was avoided. Likewise, the extracted oil presented a greater oxidative stability after applying SC-CO2 at 30 and 40 MPa, in comparison with the extractions made at lower pressures or the conventional extraction procedure. Extraction with SC-CO2 was more efficient to recover lipophilic phenolic compounds with high antioxidant capacity compared to the conventional extraction method (Folch method). A greater extraction of the different individual compounds was observed, identified and quantified by liquid chromatography coupled to tandem mass spectrometry, when the treatment pressure was increased, obtaining the highest values when the pressure was 40 MPa. On the other hand, it was also observed that after using the conventional solid/liquid extraction, modifying the extraction time and temperature as well as the solvent used, the extraction efficiency of the total phenolic compounds was higher with increasing temperature. Moreover, higher concentrations of ethanol and longer extraction times also promoted an improvement in the extraction of these compounds. Antioxidant capacity also increased when higher ethanol concentrations were used, with a longer extraction time and higher temperature. These results could translate into economic benefits derived from the valuation of by-products as opposed to their elimination in order to preserve the environment

Influence of temperature, solvent and pH on the selective extraction of phenolic compounds from tiger nuts by-products: Triple-TOF-LC-MS-MS characterization.

The aim of this study was to assess the effect of temperature, solvent (hydroethanolic mixtures) and pH on the recovery of individual phenolic compounds from 'horchata' by-products. These parameters were optimized by response surface methodology and triple-TOF-LC-MS-MS was selected as the analytical tool to identify and quantify the individual compounds. The optimum extraction conditions were 50% ethanol, 35 °C and pH 2.5, which resulted in values of 222.6 mg gallic acid equivalents (GAE)/100 g dry matter and 1948.1 µM trolox equivalent (TE)/g of dry matter for total phenolic content (TPC) and trolox equivalent antioxidant capacity (TEAC), respectively. The extraction of phenolic compounds by the conventional solvent method with agitation was influenced by temperature (p = 0.0073), and more strongly, by the content of ethanol in the extraction solution (p = 0.0007) while the pH did not show a great impact (p = 0.7961). On the other hand, the extraction of phenolic acids was affected by temperature (p = 0.0003) and by ethanol amount (p < 0.0001) but not by the pH values (p = 0.53). In addition, the percentage of ethanol influenced notably the extraction of both 4-vinylphenol (p = 0.0002) and the hydroxycinnamic acids (p = 0.0039). Finally, the main individual phenolic extracted with hydroethanolic mixtures was 4-vinylphenol (303.3 μg/kg DW) followed by spinacetin3-O-glucosyl-(1→6)-glucoside (86.2 μg/kg DW) and sinensetin (77.8 μg/kg DW)

Obtaining antioxidants and natural preservatives from food by-products through fermentation: A review

Industrial food waste has potential for generating income from high-added-value compounds through fermentation. Solid-state fermentation is promising to obtain a high yield of bioactive compounds while requiring less water for the microorganism’s growth. A number of scientific studies evinced an increase in flavonoids or phenolics from fruit or vegetable waste and bioactive peptides from cereal processing residues and whey, a major waste of the dairy industry. Livestock, fish, or shellfish processing by-products (skin, viscera, fish scales, seabass colon, shrimp waste) also has the possibility of generating antioxidant peptides, hydrolysates, or compounds through fermentation. These bioactive compounds (phenolics, flavonoids, or antioxidant peptides) resulting from bacterial or fungal fermentation are also capable of inhibiting the growth of commonly occurring food spoilage fungi and can be used as natural preservatives. Despite the significant release or enhancement of an-tioxidant compounds through by-products fermentation, the surface areas of large-scale bioreactors and flow patterns act as constraints in designing a scale-up process for improved efficiency. An in-process purification method can also be the most significant contributing factor for raising the overall cost. Therefore, future research in modelling scale-up design can contribute towards mitigating the discard of high-added-value generating residues. Therefore, in this review, the current knowledge on the use of fermentation to obtain bioactive compounds from food by-products, emphasizing their use as natural preservatives, was evaluated

Artificial Intelligence : Implications for the Agri-Food Sector

Artificial intelligence (AI) involves the development of algorithms and computational models that enable machines to process and analyze large amounts of data, identify patterns and relationships, and make predictions or decisions based on that analysis. AI has become increasingly pervasive across a wide range of industries and sectors, with healthcare, finance, transportation, manufacturing, retail, education, and agriculture are a few examples to mention. As AI technology continues to advance, it is expected to have an even greater impact on industries in the future. For instance, AI is being increasingly used in the agri-food sector to improve productivity, efficiency, and sustainability. It has the potential to revolutionize the agri-food sector in several ways, including but not limited to precision agriculture, crop monitoring, predictive analytics, supply chain optimization, food processing, quality control, personalized nutrition, and food safety. This review emphasizes how recent developments in AI technology have transformed the agri-food sector by improving efficiency, reducing waste, and enhancing food safety and quality, providing particular examples. Furthermore, the challenges, limitations, and future prospects of AI in the field of food and agriculture are summarized

Pre-treatment and extraction techniques for recovery of added value compounds from wastes throughout the agri-food chain

The enormous quantity of food wastes discarded annually force to look for alternatives for this interesting feedstock. Thus, food bio-waste valorisation is one of the imperatives of the nowadays society. This review is the most comprehensive overview of currently existing technologies and processes in this field. It tackles classical and innovative physical, physico-chemical and chemical methods of food waste pre-treatment and extraction for recovery of added value compounds and detection by modern technologies and are an outcome of the COST Action EUBIS, TD1203 Food Waste Valorisation for Sustainable Chemicals, Materials and Fuels

Gamma Irradiation and Fermentation

International audienceThis chapter discusses the applications of gamma irradiation technology for food safety, its nutritional implications, and its involvement in alcohol fermentation processes. Gamma irradiation has become an alternative technology for food sterilization due to its non-thermal character, replacing thus the conventional heating processes. Many major separate driving forces are carrying out the need of using gamma irradiation forward. One of them is the need to reduce or completely inactivate the microbial growth on food products, mainly involving food safety and nutritional purposes, and the possibility of its application after food packaging. Another major driver is the need to replace conventional heating processes for foodborne pathogen inactivation, highly consuming energy, by environmentally friendly and alternative ones. Besides food preservation, gamma irradiation has taking place for novel applications, especially involving the enhancement of alcohol fermentation processes, by directly irradiating the medium, or generating performant genetically modified strains

Novel Thermal Technologies and Fermentation

International audienceFermentation is one of the oldest methods practiced by human beings for the transformation of some food products in order to extend their storage period or shelf-life, and give them novel organoleptic properties. Moreover, during fermentation a high amount of valuable compounds with important commercial benefits are produced. Therefore, there is a need to develop energy efficient and environmentally friendly sustainable processes in order to improve fermentation-related processes. Traditionally, conventional thermal treatments have been used in food fermentation as they provide the required safety properties and the shelf-life extensions of food products. However, the organoleptic properties of the treated products can be altered and thermolabile compounds are usually damaged. As a result, alternative approaches have been sought by food industries in order to reach similar objectives in terms of safety and shelf-life extension, with preserving the treated food quality. Novel thermal technologies have been appeared as alternatives to traditional thermal approaches, and showing numerous advantages (e.g. shorter treatment time, milder temperature, etc.). Among the novel thermal technologies; radio frequency, microwaves, and ohmic heating, are the most applied. This chapter reviews the effects of these novel thermal technologies and their applications related to fermentation

Ultrasound-Assisted Lactic Acid Fermentation of Bakraei (<i>Citrus reticulata</i> cv. Bakraei) Juice: Physicochemical and Bioactive Properties

In this study, ultrasonication (US) (50 W, 30 kHz, 1–6 min) was used to increase the efficiency of Limosilactobacillus reuteri PTCC 1655 fermentation process (37 °C; 30 h) of Bakraei juice. Total sugars, pH, Brix, organic acids, vitamin C, polyphenols, antioxidant activity, α-amylase inhibition and anti-inflammatory properties were measured during the fermentation period. The results showed that by increasing the ultrasound time up to 5 min, pH, vitamin C, citric acid, and polyphenolic compounds decreased, while lactic acid, antioxidant capacity, α-amylase inhibition and anti-inflammatory properties were increased. When the ultrasound time was increased up to 6 min, compared to the non-ultrasound-treated sample, the efficiency of the fermentation process decreased and promoted a decrease in the microbial population, lactic acid levels, antioxidant activity, α-amylase inhibition, and anti-inflammatory properties of the juices. The initial anti-inflammatory activity (11.3%) of juice reached values of 33.4% and 19.5%, after US treatments of 5 and 6 min, respectively, compared to the non-sonicated juice (21.7%), after 30 h of fermentation. As a result, the use of ultrasound in the controlled fermentation process can increase the efficiency of fermentation process

New Trends in Molecular Techniques to Identify Microorganisms in Dairy Products

International audienceDairy products constitute one of the most important types of functional foods. Most of these functional properties have been attributed to their complex microbial ecosystem. Moreover, microorganisms are responsible for the broad diversity of tastes, aromas, and textures of dairy products. For instance, many bacteria make a positive contribution to the organoleptic quality of cheeses or fermented milk. However, some other bacteria may have adverse effects, or may even present a health risk from a safety point of view. Thus, it is of a paramount importance to control microbial ecosystem of dairy products. Traditionally culture-based methods have been used for the identification of microbial communities in dairy products. However, these assays can be used only for organisms that can be cultivated in vitro. In addition, there are some strains with unique biochemical characteristics and it is not possible to fit them into patterns for any characteristic genus and species already known. Limitations associated with these techniques have led to develop new molecular techniques, which are primarily based on the analysis of nucleic acids. Indeed, molecular techniques have been shown as a tool that can avoid the main limitations of conventional phenotypic procedures for the identification of microorganisms. Among the many molecular techniques, real time Polymerase Chain Reaction (PCR) and microarrays have emerged as the most commonly used methods. This chapter describes the benefits and limitations of molecular techniques in the identification of microorganisms in dairy products. Moreover, the potential applications of these techniques will be also discussed