Browsing by Author "Coelho, Elisabete"
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- Aspectos químicos y nutricionales del filete de Aloe veraPublication . Pinela, José; Añibarro-Ortega, Mikel; Barros, Lillian; Silva, Soraia P.; Coelho, Elisabete; Coimbra, Manuel A.; Ferreira, Isabel C.F.R.El Aloe vera (Aloe barbadensis Mill.) es una planta suculenta de la familia Asphodelaceae actualmente naturalizada en muchos países tropicales y subtropicales. En la medicina tradicional, se ha utilizado ampliamente durante siglos para tratar trastornos de la piel y otras enfermedades, así como por su efecto purgante [1]. Hoy en día, esta especie se usa como ingrediente para alimentos funcionales, cosméticos y medicamentos [2]. Las hojas son la parte más utilizada de la planta, en la que se pueden identificar dos fracciones principales, la corteza externa y el parénquima interno conocido como pulpa o filete. Aunque hay varios estudios sobre el Aloe vera [1,2], muchos de ellos tienen descripciones confusas, principalmente sobre el interior de la hoja, debido a los diferentes términos que se han usado indistintamente. En este sentido, en este trabajo se realizó una caracterización del valor nutricional y composición química del parénquima interno de la hoja (filete), que es la parte comestible de la planta. El filete de las hojas de Aloe vera fue separado de la cáscara y se determinó el contenido en humedad. Después, la muestra se liofilizó y se pulverizó y se determinó el contenido en proteína, grasa, cenizas, hidratos de carbono disponibles y fibra alimentaria. También se determinó la composición en ácidos orgánicos, ácidos grasos, tocoferoles, azúcares libres y polisacáridos de alto peso molecular utilizando diferentes técnicas cromatográficas. El perfil en compuestos fenólicos se caracterizó en un extracto hidroetanólico mediante HPLC-DAD-ESI/MSn. Se verificó que el filete corresponde aproximadamente al 58% de la masa de la hoja de Aloe vera y que su mayor constituyente es el agua (98%). En base seca, la fibra alimentaria resultó ser el macronutriente predominante (50.1%), constituida principalmente por manano (posiblemente acemanano), seguida por los hidratos de carbono disponibles (37.4%). Apenas 1% en grasa, 2.6% en proteína y 9% en cenizas, hacen que el filete sea un alimento de bajo poder calórico (4,5 kcal/100 g fw y 270 kcal/100 g dw). También se detectaron cantidades interesantes de α-tocoferol (5 mg/100 g dw) y ácido málico (5 g/100 g dw). Respecto al perfil fenólico, se detectaron de forma predominante cromonas (5.5 mg/g extracto) y antronas (5.3 mg/g extracto), incluyendo aloesina y aloínas A y B, respectivamente. El filete fresco de Aloe vera es un alimento bajo en calorías debido a su alto contenido en agua y bajo contenido en grasa. Además, se destaca por su contenido en tocoferoles, ácido málico y cromonas [3]. Todo esto hace que el filete de Aloe vera sea un ingrediente interesante para ser explorado tanto por la industria alimentaria como por la industria cosmética.
- Compositional features and bioactive properties of aloe vera leaf (Fillet, mucilage, and rind) and flowerPublication . Añibarro Ortega, Mikel; Pinela, José; Barros, Lillian; Ćirić, Ana; Silva, Soraia P.; Coelho, Elisabete; Mocan, Andrei; Calhelha, Ricardo C.; Soković, Marina; Coimbra, Manuel A.; Ferreira, Isabel C.F.R.This work aimed to characterize compositional and bioactive features of Aloe vera leaf (fillet, mucilage, and rind) and flower. The edible fillet was analysed for its nutritional value, and all samples were studied for phenolic composition and antioxidant, anti-inflammatory, antimicrobial, tyrosinase inhibition, and cytotoxic activities. Dietary fibre (mainly mannan) and available carbohydrates (mainly free glucose and fructose) were abundant macronutrients in fillet, which also contained high amounts of malic acid (5.75 g/100 g dw) and -tocopherol (4.8 mg/100 g dw). The leaf samples presented similar phenolic profiles, with predominance of chromones and anthrones, and the highest contents were found in mucilage (131 mg/g) and rind (105 mg/g) extracts, which also revealed interesting antioxidant properties. On the other hand, the flower extract was rich in apigenin glycoside derivatives (4.48 mg/g), effective against Pseudomonas aeruginosa (MIC = 0.025 mg/mL and MBC = 0.05 mg/mL) and capable of inhibiting the tyrosinase activity (IC50 = 4.85 mg/mL). The fillet, rind, and flower extracts also showed a powerful antifungal activity against Aspergillus flavus, A. niger, Penicillium funiculosum, and Candida albicans, higher than that of ketoconazole. Thus, the studied Aloe vera samples displayed high potential to be exploited by the food or cosmetic industries, among others.
- Microwave hydrodiffusion and gravity: an emergent technology for green extraction of non-volatile compoundsPublication . Passos, Cláudia P.; Calvão, João; Ferreira, Sónia; Jorge, Ricardo; Fernandes, Pedro A.R.; Martins, Vitor Manuel Ramalheira; Coelho, Elisabete; Wessel, Dulcineia F.; Cardoso, Susana M.; Nunes, Cláudia; Coimbra, Manuel A.Microwave technologies are more and more present in food applications due to their performance in shortening the time of treatments such as drying, pasteurization, defrosting, or postharvesting. While solvent-free microwave extraction has been extensively used as a green procedure for essential oil and volatile compounds from aromatic herbs [1], its applications have been extended to enhance extraction of phytocompounds simultaneously with drying. In this work, microwave hydrodiffusion and gravity was performed in a laboratory microwave oven (NEOS-GR, Milestone, Italy), in order to evaluate its efficiency in the extraction of nonvolatile compounds such as: free sugars, f1bers, colour, and phenolic compounds. Five different matrices were tested: broccoli by-products (90% moisture), apple pomace (80% moisture), spent coffee grounds (65% moisture), Pterospartum tridentatum inflorescences, and brown algae, the latter two in dried state. The flow behaviour was very dependent on matrix (Figure 1): for broccoli, the time to obtain 50 ml aliquots increased along time while for apple pomace it was always the same after the initial and final heating periods, and for the spent coffee grounds it was always decreasing. Good recoveries were observed when using high water content matrices, such as apple pomace and broccoli. However, when using hydrated matrices, such as brown algae and Pterospartum tridentatum inflorescences, it was observed that the amount of material extracted is very low. In the case of spent coffee qrounds (a material where water is added to the ground coffee when preparing espresso coffee), the initial low recoveries can be overcome by the eo-addition of ethanol, allowing to obtain fractions rich in phenolic compounds, as well as brown compounds (with antioxidant activity) and caffeine. NEOS-GR, using microwave hydrodiffusion and gravity is a green extraction technology obtain hydrophilic compounds from wet matrices using its own water, allowing the extraction of valuable non-volatile compounds.
- Microwave hydrodiffusion and gravity: an emergent technology for green extraction of non-volatile compoundsPublication . Passos, Cláudia P.; Calvão, João; Ferreira, Sónia; Jorge, Ricardo; Fernandes, Pedro A.R.; Martins, Vitor Manuel Ramalheira; Coelho, Elisabete; Wessel, Dulcineia F.; Cardoso, Susana M.; Nunes, Cláudia; Coimbra, Manuel A.Microwave technologies are more and more present in food applications due to their performance in shortening the time of treatments such as drying, pasteurization, defrosting, or post-harvesting [1]. While solvent-free microwave extraction has been extensively used as a green procedure for essential oil and volatile compounds from aromatic herbs [2], its applications have been extended to enhance extraction of phytocompounds simultaneously with drying. In microwave drying, operational cost is lower because energy is not consumed in heating the walls of the apparatus or the environment [3].