Tangerine (Citrus reticulata. CRP) and grapefruit (Citrus paradisi. CPP) pectins obtained by ultrasound-assisted extraction (UAE) and conventional extraction (CE) using citric acid were characterized to establish their potential uses as an alternative source of commercial pectin. The pectins obtained by UAE and CE presented a pseudoplastic fluid characteristic with shear thinning behavior, a high esterification degree (CRP 82.30-71.81% and CPP 84.25-72.15%) and were of commercial quality based on galacturonic acid content (CRP 76.03% and CPP 76.03-71.01%). CPP presented greater viscosimetric molecular weight than CRP. Meanwhile, CRP presented greater polyphenol and protein content with respect CPP. The functional properties were influenced by citrus source and extraction method. UAE favored greater yields in a shorter time (CPP: 26.05%, 30 min; CRP: 13.46%, 15 min) compared to CE. UAE combined with the use of citric acid offers an effective alternative for obtaining high-quality pectins with lower polluting effluent, time and energy requirements. Pectina cítrica obtenida por extracción asistida por ultrasonido: propiedades fisicoquímicas, estructurales, reológicas y funcionales RESUMEN Pectinas de mandarina (Citrus reticulata, PCR) y pomelo (Citrus paradisi, PCP) obtenidas vía extracción asistida por ultrasonido (EAU) y convencional (EC) con ácido cítrico fueron caracterizadas para establecer su potencial uso como una fuente alternativa de pectina comercial. Las pectinas obtenidas por EAU y EC presentaron características de fluido pseudoplástico con un comportamiento de adelgazamiento por cizalladura, alto grado de esterificación (CRP 82.30-71.81% and CPP 84.25-72.15%), y calidad comercial por el contenido de ácido galacturónico (CRP 76.03% and CPP 76.03-71.01%). PCP presentaron mayor peso molecular viscosimétrico comparado a PCR. Mientras PCR presentaron mayor contenido de polifenoles, y proteínas con respecto a PCP. Las propiedades funcionales fueron influenciadas por la fuente cítrica y el método de extracción. La EAU favoreció los mayores rendimientos a menor tiempo: PCP (26.05±0.49%, 30 min) y PCR (13.46±1.79%, 15 min) comparada con EC. La EAU representa una alternativa eficaz para la obtención de pectinas de alta calidad, con menores efluentes contaminantes, tiempo y energía.

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Analysis was done of the composition and bioactive factor content of whole meal, processed meal and protein concentrate from a cowpea cultivar (Vigna unguiculata L. Walp var. IT86D-719) grown in Yucatan, Mexico and of changes in these parameters after soaking and dehulling. Both meals had a high protein content (247.53 and 257 g kg −1 dry matter (DM) respectively). The protein concentrate was rich in protein (786 g kg −1 DM) and lipids (58.47 g kg −1 DM) and had an amino acid profile similar to that of the processed meal. The amino acid profiles of the meals almost covered human dietary requirements based on FAO/WHO/UNU-suggested profiles but were deficient in sulphur amino acids. Trypsin inhibitor activity was high in both meals compared with levels found in previous studies. Trypsin inhibitor activity in the concentrate was not eliminated but was significantly reduced. Lectin activity, tannin levels, phytate levels and α-amylase inhibitor activity were relatively low in the meals, and cyanogenic glucosides were not detected. Residual amounts of α-amylase inhibitors, tannins and phytate were observed in the concentrate, and lectin activity was not detected. Results indicate that V. unguiculata L. Walp var. IT86D-719 meals and protein concentrate are good potential foodstuffs in the Yucatan region.

Marine microalgae are a promising feedstock for biofuel production given their high growth rates and biomass production together with cost reductions due to the use of seawater for culture preparation. However, different microalgae species produce different families of compounds. Some compounds could be used directly as fuels, while others require thermochemical processing to obtain quality biofuels. This work focuses on the characterization of three marine microalgae strains native in Mexico and reported for the first time. Ultrastructure and phylogenetic analysis, suggested that they belong to Nannochloropsis sp. (NSRE-1 and NSRE-2) and Nannochloris sp. (NRRE-1). The composition of their lipid fractions included hydrocarbons, triacylglycerides (TAGs), free fatty acids (FFAs) and terpenes. Based on theoretical estimations from TAG and FFA composition, the potential biodiesels were found to comply with six of the seven estimated properties (ASTM D6751 and EN 14214). On the other hand, hydrocarbons and terpenes synthesized by the strains have outstanding potential as precursors for the production of other renewable fuels, mainly green diesel and bio-jet fuel, which are “drop-in” fuels with quality properties similar to fossil fuels. The validity of this theoretical analysis was demonstrated for the oxygenates of strain NSRE-2, which were experimentally hydrodeoxygenated, obtaining a high-quality renewable diesel as the reaction product.

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