Efecto de la germinación sobre la composición química y la actividad antioxidante de aceites de linaza (Linum usitatissimum L).

The present study was carried out to determine the changes in proximate composition and physicochemical characteristics of flaxseed during germination. Flaxseed was germinated for 4 days and observations were taken every day throughout the study. Changes in the seed reserve and antioxidant activity were determined during germination. The oil content of the cultivar decreased from 35.10 to 27.22%. During the germination period, the total protein content increased to 23.84%. Germinated flaxseed showed significantly higher unsaturated as compared to saturated fatty acid ratios and higher calculated oxidizability (Cox) values. The Saponification value ranged from 182 to 192 mg KOH·g–1 oil during germination. The highest peroxide value (2.4 mequiv O2·kg−1 oil) was observed at the end of germination. The unsaponifiable contents ranged from 1.62 to 1.18%. The oxidation value of the oil samples were statistically in the same range (4.1–6.4%). After 4 days of germination, oil stability was reduced to 1.0 h. The increase in ascorbic acid content was steady. Total phenolic acid contents differed significantly. The greatest concentration was detected in non germinated flaxseed oil. Germinated Flaxssed oil showed an important free radical scavenging activity towards 1-1-diphenyl-2-picrylhydrazyl (DPPH) free radicals.El presente estudio se llevó a cabo para determinar los cambios en la composición y características físico-químicas de aceites de linaza durante la germinación. La linaza se germinó durante 4 días y el estudio se realizó todos los días durante este proceso. Se determinaron los cambios en la reserva de las semilla y la actividad antioxidante. El contenido de aceite de los cultivos disminuyó de 35,10 a 27,22%. Durante este periodo, el contenido de proteína total aumentó a 23,84%. La linaza germinada mostró valores significativamente más altos de la relación de ácidos grasos insaturados frente a saturados y mayor facilidad de oxidación (Cox). El índice de saponificación varió desde 182 hasta 192 mg KOH·g−1 de aceite durante la germinación. El índice de peróxido más alto (2,4 mequiv O2·kg−1 de aceite) se observó al final de la germinación. El contenido de materia insaponificable varió desde 1,62 hasta 1,18%. La oxidación de las muestras de aceite fueron estadísticamente del mismo rango (4.1 a 6.4%). Después de 4 días de germinación, la estabilidad del aceite se redujo a 1,0 h. El aumento en contenido de ácido ascórbico fue estable. Los contenidos totales de ácidos fenólicos diferían significativamente. La mayor concentración se detectó en el aceite de linaza no germinado. El aceite de linaza germinado mostró una importante actividad de eliminación de radicales libres hacia 1-1-difenil-2-picrilhidrazil (DPPH)

Alterações nas reservas de sementes de Dalbergia nigra ((Vell.) Fr. All. ex Benth.) durante a hidratação

Seed imbibitions is the first stage of the germination process and is characterized by the hydration of tissues and cells and the activation and/or induction of the enzymes responsible for mobilizing reserves for respiration and the construction of new cell structures. The objective of this study was to investigate the alterations in reserve substances during slow hydration of Bahia Rosewood (Dalbergia nigra) seeds in water. Seeds from two different lots (Lot I and II) were placed in saturated desiccators (95-99% RH) to hydrate at 15 and 25 °C until water contents of 10, 15, 20 and 25% were reached. At each level of hydration, changes in lipid reserves, soluble carbohydrates, starch and soluble proteins were evaluated. The mobilization of reserves was similarly assessed in both lots, with no differences being observed between the two hydration temperatures. Lipid contents showed little variation during hydration, while the contents of soluble carbohydrates and starch decreased after the 15% water content level. Soluble proteins showed a gradual tendency to decrease between the control (dry seeds) up to 25% water content

Relationship between the structure of the flavone-C-glycosides of flax (Linum usitatissimum L.) and their biological activities

International audienceAtibiotics are one of the most important discoveries that have saved and is saving millions of lives in the world, but the emergence of resistant bacteria induces little or not effective for these synthetic products. In some situations the appearance of resistance prevents the treatment of infections caused by bacteria. The discovery of alternative antimicrobial agents has become urgently required.Many products of plant origin, in particular the class of flavonoids, exhibit antibacterial activity often associated with a high level of antioxidant power. Despite the many studies on this issue, the relationship between structure and function is currently poorly understood. To fill this gap, the biological activity of 12 flavone C-glycosides structurally close was studied. The structural variability of these compounds (derived from apigenin and luteolin) depends on the position and nature of the sugars, the number of hydroxyl groups and the presence of a methyl group.Thus, orientin, isoorientin, vitexin, isovitexin, swertisin, swertiajaponin, carlinoside, schaftoside, lucenin-1, lucenin-2, vicenin-1 and vicenin-2 were extracted from the aerial part of winter flax (Linum usitatissimum). The hydroalcoholic extract was purified by preparative HPLC and by the drowning-out crystallization method. Then, the control of the purity (greater than 99%) and the confirmation of the chemical structures were carried out by NMR and LC/MS. Antioxidant activity was tested by methods such as DPPH and FRAP and antimicrobial potential was assessed using common foodborne pathogens such as P. aeruginosa, E. coli, L. monocytogenes, L. innocua, S. arizonae, E. faecalis, S. aureus, B. subtilis