Effect of porous structure and spreading pressure on the storage stability of red onion microcapsules produced by spray freezing into liquid cryogenic and spray drying

8 páginasRed onion microcapsules were produced by spray freezing into liquid cryogenic (SFLC) and spray drying (SD) and their anthocyanin contents were evaluated kinetically at different water activities () at 35 °C. The spreading pressure-area isotherms were determined at 35 °C. These isotherms provide important information about the different phases of adsorbed water present in SD and SFLC capsules, which can be related to minimal integral entropy and to chemical stability during storage. The porosity of the microcapsules was examined using low-temperature adsorption of nitrogen. The maximum anthocyanin stability occurred at from 0.108 to 0.318, and 0.108 to 0.515, for SD and SFLC, respectively. SD products were nonporous whereas SFLC were mesoporous. The tendency to contraction of the adsorbed water film was compared with the minimum integral entropy and was proposed as a new stability criterion to predict suitable storage conditions of dehydrated foods

Advances in cryopreservation of vanilla (Vanilla planifolia Jacks.) shoot-tips: assessment of new biotechnological and cryogenic factors

The effect of dehydration, cryopreservation, and reculture conditions on growth recovery (%) of vanilla (Vanilla planifolia) shoot-tips was evaluated using a D-cryoplate procedure. Tissues were excised from in vitro grown plantlets, preconditioned on MS semisolid medium supplemented with 0.15 M trehalose for 1 d, loaded in a solution of 0.4 M sucrose or trehalose and 2 M glycerol for 30 min, and dehydrated within a laminar flow cabinet for various durations (30, 60, 90, 120, 150, and 180 min). The same preconditioning and loading treatments were compared using dehydration with vitrification solutions (PVS2 or PVS3) for 30 min at room temperature according to droplet-vitrification and V-cryoplate methods. The highest (33%) recovery of cryopreserved shoot-tips was achieved using the D-cryoplate method after 0.15 M trehalose preconditioning, loading with sucrose-glycerol solution and desiccation for 180 min. DSC analyses revealed that the osmotically active water (OAW) content of the shoot-tips was reduced from 77% (fresh weight basis) to 17% after the only effective drying duration (180 min). Melting endotherms indicated that crystallization events accompanied cryopreservation of the tissues. Proliferation of multiple shoots was obtained by indirect organogenesis. Histological analysis of the explants during post-cryopreservation recovery confirmed the organogenic nature of the callus formed after 3–4 mo of reculture in the dark on semisolid multiplication medium. This was followed by a secondary organogenesis on MS medium with kinetin (2 mg L−1) and exposure to a photoperiod. At present, this is the most optimized cryopreservation protocol for shoot-tips of V. planifolia.Fil: Hernández Ramírez, F.. Universidad Veracruzana; MéxicoFil: Dolce, Natalia Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Flores Castaños, O.. Universidad Veracruzana; MéxicoFil: Rascón, M.P.. Universidad Veracruzana; MéxicoFil: Ángeles Álvarez, G.. Instituto de Ecología; MéxicoFil: Folgado, R.. No especifíca;Fil: González Arnao, M.T.. Universidad Veracruzana; Méxic

Alérgenos en el vino

Allergies and/or food intolerances occur in people who are sensitive to certain compounds, called allergens, which are safe for the majority of the population. Wine, despite the many benefits it can provide through its moderate consumption, thanks to its polyphenol content, contains allergens, which if not known, can cause health problems in consumers. The most important allergens that the wine contains (or may contain) can be: endogenous (histamine) or exogenous. Exogenous allergens may come from conservation (sulfites), or fining agents (egg white; casein and caseinates; isinglass, and gluten). To date, the only ones that appear on the labeling are sulfites. This article presents a review of this topicLas alergias y/o intolerancias alimentarias se producen en personas que son sensibles a determinados compuestos, denominados alérgenos, que son inocuos para la inmensa mayoría de la población. El vino, a pesar de los múltiples beneficios que puede aportar mediante su consumo moderado, gracias a su contenido en polifenoles, contiene alérgenos, que si no se conocen, pueden provocar problemas de salud en los consumidores. Los alérgenos más importantes que contiene (o puede contener) el vino pueden ser: endógenos (histamina) o exógenos. Los exógenos pueden provenir de la conservación (sulfitos) o de la clarificación (clara de huevo; caseína y caseinatos; cola de pescado; y gluten). Hasta la fecha, los únicos que aparecen en el etiquetado son los sulfitos. En este artículo se presenta una revisión de este tema