A study of the effect of dietary fiber fractions obtained from artichoke (<i>Cynara cardunculus L. var. scolymus</i>) on the growth of intestinal bacteria associated with health

The effect of different fractions enriched in soluble fiber obtained from artichoke using citric acid or citric acid/hemicellulase on the selective growth of Lactobacillus plantarum 8114 and Bifidobacterium bifidum ATCC 11863 was evaluated. Gompertz modeling of Lactobacillus plantarum 8114 growth showed a higher specific growth rate (μ: 0.16 h−1) in the presence of fractions isolated from stems using hemicellulase (fraction A) than in the presence of glucose (μ: 0.09 h−1). In the case of Bifidobacterium bifidum 11863, the highest μ was obtained for the microorganism grown in the presence of fraction A and for the fraction isolated from stems without hemicellulase, their rate being twice that observed for glucose (0.04 h−1). The positive prebiotic activity scores observed with respect to Escherichia coli 25922 indicated that fibers assayed are metabolized as well as glucose by Lactobacillus plantarum 8114 and Bifidobacterium bifidum ATCC 11863 and that they are selectively metabolized by these microorganisms. The potential capacity to selectively stimulate the growth of intestinal bacteria associated with health shown by fraction A can be ascribed to its high inulin and low methylation degree pectin contents.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Hydrolytic and Oxidative Stability of l-(+)-Ascorbic Acid Supported in Pectin Films: Influence of the Macromolecular Structure and Calcium Presence

The hydrolytic and oxidative stability of l-(+)-ascorbic acid (AA) into plasticized pectin films were separately studied in view of preserving vitamin C activity and/or to achieve localized antioxidant activity at pharmaceutical and food interfaces. Films were made with each one of the enzymatically tailored pectins (50%, 70%, and 80% DM; Cameron et al. Carbohydr. Polym.2008, 71, 287–299) or commercial high methoxyl pectin (HMP; 72% DM). Since AA stability was dependent on water availability in the network, pectin nanostructure affected the AA kinetics. Higher AA retention and lower browning rates were achieved in HMP films, and calcium presence in them stabilized AA because of higher water immobilization. Air storage did not change AA decay and browning rates in HMP films, but they significantly increased in Ca-HMP films. It was concluded that the ability of the polymeric network to immobilize water seems to be the main factor to consider in order to succeed in retaining AA into film materials.The isolation and characterization of the PME and tailoring of demethylated pectins used in this work were supported by the U.S. Department of Agriculture, Agricultural Research Service, Project Numbers 6618-41000-016-00 and 6618-41000-015-00, and National Institute of Food and Agriculture, National Research Initiative, Award Number 2009-35503-05205. The present study was supported by the University of Buenos Aires (UBA), National Scientific and Technical Research Council of Argentina (CONICET) and National Agency for the Promotion of Science and Technology (ANPCyT) of Argentina.Peer reviewe

Carrot pectin enriched fraction as a functional additive: Antioxidant and gelling effects in a model spreadable chia oil-in-water emulsion

An orange-colored pectin-enriched fraction previously obtained from discarded carrots (CPEF; 42%-methylated, 14%-acetylated, 50% uronic acids) through high-power-ultrasound and bacterial hemicellulase, carrying carotenes, lutein, and α-tocopherol, was evaluated as a food additive for its capacity to stabilize a model spreadable 20:80 w/w chia-oil-in-water emulsion. The optimal formulation for physical stability after 45 days at 25 °C was first determined through a Box-Behnken design with three independent variables (CPEF and Tween 80 concentrations, and ultrasound-emulsifying time). The optimized CPEF emulsion constituted a calcium-crosslinked “weak-gel type” network formed by the contribution of oil droplets. During storage, its elastic modulus increased probably by CPEF adsorption at the interface. In the optimized emulsion, CPEF prevented oil-phase oxidation by the air-oxygen entrapped, through the 45 day storage (peroxide index: 7.6meq/kg oil-phase; TBARS: 6.0 mg MDA eq/kg oil-phase), based on the differential partition of antioxidants between the interior of the oil droplets (apolar carotenes) and the oil-water interface (more polar tocopherol), the latter formed by the nonionic Tween 80 emulsifier. Despite unfavorable conditions for the preservation of food systems (water activity = 0.979; pH 5.4; air-oxygen; 25 °C), the emulsion orange-color was highly stable during storage due to the stability of carotenoids. CPEF is thus a useful functional additive for food preservation.Fil: Idrovo Encalada, Alondra M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias (ITAPROQ); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Perez, Carolina Daiana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Rossetti, Luciana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina.Fil: Rojas, Ana M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias (ITAPROQ); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Fissore, Eliana N. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias (ITAPROQ); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina