ABSTRACT
Nowadays, consumers are more conscious about healthier products consumption benefits. Astaxanthin obtained from the microalgae Haematococcus pluvialis represents a natural ingredient for the nutraceutical and functional food industries. It is claimed that astaxanthin has much stronger antioxidant activity than vitamin E and ß-carotene, providing different health benefits. However, the unstable structure of the molecule limits its application in functional foods development. Therefore, the present study evaluates the effect of five independent formulation and process variables for natural astaxanthin oleoresin encapsulation using an external ionic gelation technique. Response surface methodology can be used for studying the effect of several factors at different levels and their influences on each other, which overcomes the shortcoming of the traditional orthogonal method. The results showed that alginate and CaCl2 concentrations have a significant effect on particles size obtained, while alginate/oleoresin ratio and surfactant concentration greatly influence the astaxanthin oleoresin release rate. In vitro studies under simulated intestinal conditions showed that astaxanthin oleoresin release process can be described by Hopfenberg model. Three mathematical models were obtained for predicting particle size, astaxanthin release rate and encapsulation yield under different process conditions, providing a platform for microencapsulation technology optimization for healthy food design.
Subject(s)
Alginates/chemistry , Drug Carriers/chemistry , Microspheres , Capsules , Chlorophyceae/chemistry , Drug Liberation , Particle Size , Xanthophylls/chemistryABSTRACT
The study of microalgal culture has been growing in recent decades, because the cellular structure of microalgae has diverse highly valuable metabolites that have attract attention of numerous companies and research groups. The pigment astaxanthin is considered one of the most powerful antioxidants in nature. The microalga Haematococcus pluvialis was proposed as one of the best natural astaxanthin sources, because it can accumulate high amount of the pigment. In this work, we studied different stress treatments on H. pluvialis growth cultures as well as astaxanthin production under autotrophic growth conditions. The results showed that extending nitrogen starvation before increasing radiation intensity up to 110 µmol photons m-2 s-1 during late the palmella cell phase incremented the astaxanthin concentration up to 2.7% of dry biomass with an efficient light energy utilization during the stress stage.
Subject(s)
Autotrophic Processes , Cell Culture Techniques , Chlorophyta/metabolism , Microalgae/metabolism , Pigments, Biological/metabolism , Stress, Physiological , Biomass , Chlorophyta/growth & development , Chlorophyta/physiology , Chlorophyta/radiation effects , Dose-Response Relationship, Radiation , Microalgae/growth & development , Microalgae/physiology , Microalgae/radiation effects , Nitrogen/metabolism , Sunlight , Xanthophylls/biosynthesisABSTRACT
Carboxypeptidase A (CPA) is a metalloexopeptidase that catalyzes the hydrolysis of the peptide bonds that are adjacent to the C-terminal end of a polypeptide chain. The enzyme preferentially cleaves over C-terminal L-amino acids with aromatic or branched side chains. This is of main importance for food industry because it can be employed for manufacturing functional foods from different protein sources with reduced hydrophobic amino acid content for patients with deficiencies in the absorption or digestion of the corresponding amino acids. In that way, strategies for effective multipoint covalent immobilization of CPA metalloenzyme on chitosan beads have been developed. The study of the ability to produce several chemical modifications on chitosan molecules before, during and after its coagulation to form carrier beads lead in a protective effect of the polymer matrix. The chemical modification of chitosan through the use of an N-alkylation strategy produced the best derivatives. N-alkyl chitosan derivative beads with D-fructose presented values of 0.86 for immobilization yield, 314.6 IU g-1 bead for initial activity of biocatalyst and were 5675.64-fold more stable than the free enzyme at 55 °C. Results have shown that these derivatives would present a potential technological application in hydrolytic processes due to both their physical properties, such as low swelling capacity, reduced metal chelation ability and bulk mesoporosity, and increased operational stability when compared with soluble enzyme.
Subject(s)
Carboxypeptidases A/chemistry , Chitosan/chemistry , Enzymes, Immobilized/chemistry , Biocatalysis , Enzyme Stability , Fructose/chemistry , Hot TemperatureABSTRACT
Los marcadores serológicos comúnmente utilizados en el diagnóstico de la enfermedad celíaca son los anticuerpos antigliadina (AG) y antiendomisio (AE). Recientemente (1997) se identificó a la transglutaminasa de tejido (tTG) como el principal autoantígeno de los anticuerpos AE. El objetivo de este trabajo fue determinar la sensibilidad y especificidad de testes de ELISA desarrollados en base a la utilización de estructuras moleculares definidas como antígenos de captura para los anticuerpos AG y AE. Como antígenos inmovilizados para los anticuerpos AG se ensayaron tres péptidos de sínteses correspondientes a la región amino terminal de la alfa gliadina y para los AE, la transglutaminasa de hígado de cobayo. Se examinaron un total de 80 sueros correspondientes a: pacientes celíacos, no tratados y tratados, controles enfermos no celíacos y controles sanos. Rango de edad: 7 meses a 14 años. Se obtuvo una sensibilidad del 97 por ciento y una especificidad 86 por ciento para la IgG determinada utilizando como antígeno uno de los tres péptidos de síntesis (correspondiente a los residuos 31-55 de la alfa gliadina). Este péptido aparece como un antígeno altamente sensible y más específico que la gliadina. El mejor resultado, con un 100 por ciento de especificidad y sensibilidad, se obtuvo en la determinación de la IgA anti-tTG, lo que destaca la relevancia de estos anticuerpos como marcadores serológicos de la enfermedad celíaca.
Subject(s)
Child, Preschool , Child , Infant , Adolescent , Humans , Male , Female , Antibodies/blood , Antigens/blood , Celiac Disease/diagnosis , Gliadin/immunology , Peptides/immunology , Transglutaminases/immunology , Biomarkers , Celiac Disease/enzymology , Enzyme-Linked Immunosorbent Assay , Gliadin/biosynthesis , Immunoglobulin A/blood , Immunoglobulin G/blood , Sensitivity and Specificity , Serologic TestsABSTRACT
Los marcadores serológicos comúnmente utilizados en el diagnóstico de la enfermedad celíaca son los anticuerpos antigliadina (AG) y antiendomisio (AE). Recientemente (1997) se identificó a la transglutaminasa de tejido (tTG) como el principal autoantígeno de los anticuerpos AE. El objetivo de este trabajo fue determinar la sensibilidad y especificidad de testes de ELISA desarrollados en base a la utilización de estructuras moleculares definidas como antígenos de captura para los anticuerpos AG y AE. Como antígenos inmovilizados para los anticuerpos AG se ensayaron tres péptidos de sínteses correspondientes a la región amino terminal de la alfa gliadina y para los AE, la transglutaminasa de hígado de cobayo. Se examinaron un total de 80 sueros correspondientes a: pacientes celíacos, no tratados y tratados, controles enfermos no celíacos y controles sanos. Rango de edad: 7 meses a 14 años. Se obtuvo una sensibilidad del 97 por ciento y una especificidad 86 por ciento para la IgG determinada utilizando como antígeno uno de los tres péptidos de síntesis (correspondiente a los residuos 31-55 de la alfa gliadina). Este péptido aparece como un antígeno altamente sensible y más específico que la gliadina. El mejor resultado, con un 100 por ciento de especificidad y sensibilidad, se obtuvo en la determinación de la IgA anti-tTG, lo que destaca la relevancia de estos anticuerpos como marcadores serológicos de la enfermedad celíaca. (AU)
