143 research outputs found
A novel procedure to measure the antioxidant capacity of Yerba maté extracts
Yerba maté extracts have in vitro antioxidant capacity attributed to the presence of polyphenolic compounds, mainly chlorogenic acids and dicaffeoylquinic acid derivatives. DPPH is one of the most used assays to measure the antioxidant capacity of pure compounds and plant extracts. It is difficult to compare the results between studies because this assay is applied in too many different conditions by the different research groups. Thus, in order to assess the antioxidant capacity of yerba maté extracts, the following procedure is proposed: 100 ”L of an aqueous dilution of the extracts is mixed in duplicate with 3.0 mL of a DPPH 'work solution in absolute methanol (100 ”M.L-1), with an incubation time of 120 minutes in darkness at 37 ± 1 °C, and then absorbance is read at 517 nm against absolute methanol. The results should be expressed as ascorbic acid equivalents or Trolox equivalents in mass percentage (g% dm, dry matter) in order to facilitate comparisons. The AOC of the ethanolic extracts ranged between 12.8 and 23.1 g TE % dm and from 9.1 to 16.4 g AAE % dm. The AOC determined by the DPPH assay proposed in the present study can be related to the total polyphenolic content determined by the Folin-Ciocalteu assay
Effect of freezing and processing technologies on the antioxidant capacity of fruit pulp and jelly
Optimization of callus and cell suspension cultures of Barringtonia racemosa (Lecythidaceae family) for lycopene production
Caracterização isozimĂĄtica e atividade de peroxidase em folhas de plantas hiperĂdrica, intermediĂĄria e normal de Bidens pilosa L. mantidas in vitro
Cassava starch edible coating incorporated with propolis on bioactive compounds in strawberries
Vitrification of carnation in vitro: Changes in cell wall mechanical properties, cellulose and lignin content
peer reviewedVitrification of internodes of carnation was brought about by culturing in liquid medium. Cell wall extensibility of these internodes was kinetically followed in comparison to that of normal plants using the constant stress method. Liquid culture induced increased immediate and total deformation capacities of the walls from the second day. Measurements indicated that these deformation capacities involved plastic properties rather than elastic ones. These changes were paralleled by decreased relative levels of cellulose and lignin. © 1987 Martinus Nijhoff/Dr W. Junk Publishers
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