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RESEARCH PRODUCT

Innovative extraction and separation technologies to improve the recovery of microalgae nutrients and bioactive compounds with potential beneficial effects on human health

subject

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Las microalgas son ricas en una gran variedad de compuestos bioactivos, que incluyen proteínas, polifenoles, polisacáridos, pigmentos, minerales, vitaminas, etc., que pueden utilizarse o separarse directamente para obtener componentes de mayor valor. La extracción y la separación son pasos clave en la obtención y posterior procesamiento de los productos relacionados con las microalgas, representando las tecnologías innovadoras de procesado una estrategia innovadora y eficiente para mejorar la calidad de estos productos. Actualmente, las microalgas y sus compuestos (nutrientes, compuestos bioactivos, etc.) se utilizan como alimento y también con finalidades desde el punto de vista de salud, así pues, es necesario investigar su impacto en la salud intestinal humana. En la presente tesis, se observó como la aplicación de los pulsos eléctricos (PE), así como las extracciones con líquidos presurizados (PLE) y ultrasonidos (USN) mejoraron la eficiencia de extracción de nutrientes y compuestos bioactivos a partir de microalgas. Se ha seleccionado Spirulina (Arthrospira platensis), Chlorella y Phaeodactylum tricornutum para extraer los compuestos debido a su alto contenido en los mismos. Mediante microscopía electrónica de barrido (SEM) se observó como tanto los PEF como los USN rompieron la estructura de la pared celular de las microalgas durante el proceso de extracción. Además, cuando se usó la combinación PE + PLE, el rendimiento de nutrientes y compuestos bioactivos a partir de Spirulina (Arthrospira platensis) aumentó considerablemente (p 0.05) en la fracción de sacáridos de alto peso molecular (300, 500 kDa). El uso de técnicas de extracción innovadoras aumentó significativamente la capacidad antioxidante de los extractos de microalgas (p 0.05) effect on the high molecular weight saccharides fraction (300, 500 kDa). In addition, this study explored the potential effect of microalgae extracts on the human gut health. The use of innovative extraction techniques significantly increased the antioxidant capacity of the microalgae extracts (p < 0.05), which was attributed to a higher yield of bioactive compounds. Spirulina (Arthrospira platensis) and Phaeodactylum tricornutum extracts significantly (p < 0.05) modulated the in vitro activation of the inflammatory NF-κB pathway on epithelial intestinal cell models. In addition, microalgae extracts inhibited the growth of foodborne and potential pathogenic bacteria (strains of Listeria, Staphylococcus, Salmonella, Escherichia )(p < 0.05), while promoting (p < 0.05) the growth of potentially beneficial bacteria (including Lactobacillus and Bifidobacterium strains). In vitro gut microbiota was modulated by Spirulina and P. tricornutum extracts, and after in vitro gastrointestinal digestion, microalgae extracts showed more evident benefits on specific microbial genera (Bifidobacterium) by targeted qPCR. In addition to microalgae, macroalgae bioactive compounds-Laminaria japonica polysaccharides (LJP), the main extract of kelp, has been widely used in the food industry due to their health effects such as regulating blood lipids, lowering blood sugar, antiinflammatory, and antioxidation. This study also investigated the effects of Laminaria japonica polysaccharides (LJP) on the rheological, gelatinization, and retrogradation properties of wheat starch (WS) gels. Dynamic rheological test showed that the addition of LJP decreased the storage and loss modulus. LJP significantly decreased the peak viscosity, breakdown, and setback value of WS. Moreover, LJP incorporation significantly reduced the WS gel hardness during storage. SEM results showed that the addition of LJP improved the structure of WS gel. The short and long-range ordered structure showed that the relative crystallinity and formation of ordered structure were reduced with the addition of LJP. Overall, this study established a new protocol for the efficient extraction of high-added-value compounds from microalgae by using innovative approaches (PEF, PLE, and USN). The innovative extraction technology combined with membrane separation technology enhanced the separation efficiency of microalgae´ polysaccharides. Moreover, microalgae extracts obtained through innovative extraction techniques have shown potential benefits for the human gut health. In addition, this study explored the ability of macroalgae polysaccharides to improve food qualities and found that LJP polysaccharides improved the quality of baked products, suggesting that the bioactive compounds of microalgae may also have the potential to improve food qualities, which needs further investigation in the future. This thesis provides novel data for the extraction, separation, and application of algae bioactive compounds with potential benefits to human health, which provides more ideas for the development and application of algae products.