Volume 50, Issue 1, January 2013, Pages 320-325
a
CBQF/Escola Superior de Biotecnologia, Universidade Católica
Portuguesa, Rua Dr. António Bernardino de Almeida, P-4200-072 Porto,
Portugal
b Department of Chemical Engineering, University of Porto, Rua Dr. Roberto Frias, P-4200-465 Porto, Portugal
c CEBAL - Centro de Biotecnologia Agrícola e Agro-alimentar do Baixo Alentejo e Litoral, Rua Pedro Soares, Apartado 6158, P-7801-908 Beja, Portugal
b Department of Chemical Engineering, University of Porto, Rua Dr. Roberto Frias, P-4200-465 Porto, Portugal
c CEBAL - Centro de Biotecnologia Agrícola e Agro-alimentar do Baixo Alentejo e Litoral, Rua Pedro Soares, Apartado 6158, P-7801-908 Beja, Portugal
Abstract
Antioxidants are secondary metabolites in plants,
designed to protect them from abiotic stress; however, they may also
improve one's general health, following regular ingestion. Since most
foods from plant origin are
consumed only after processing and formulation, the final activity
exhibited by their antioxidants may be rather different from that in the
original plant. Ten plants empirically used in Portugal
in traditional medicine were accordingly studied - agrimony (Agrimonia
eupatoria), eucalyptus (Eucalyptus globulus), walnut-tree (Juglans
regia), myrtle (Myrtus communis), raspberry (Rubus idaeus), sage (Salvia
sp.), savory (Satureja montana), sweet-amber (Hypericum androsaemum),
thyme (Thymus vulgaris) and yarrow (Achillea millefolium), for total
antioxidant capacity and total phenolic content. Significant variations
were found between fresh and frozen forms: most plants decreased those features by 30-80 %. However, weather conditions prevailing during plant
growth also had a significant impact, besides postharvest storage
conditions - especially in the case of antioxidant capacity. Typically, a
decrease occurred throughout processing and storage, which was maximum
for myrtle and minimum for yarrow. The results of this research are
useful in attempts to preserve the antioxidant content of plant-derived foods, or of plant
additives in foods, via rational manipulation of processing conditions
after harvest and throughout storage. © 2012 Elsevier Ltd.
Author keywords
ABTS +; Fresh plant; Frozen plant; Packed plant; Stored plant; Total phenolics
Indexed keywords
ABTS +; Fresh plants; Frozen plant; Packed plant; Stored plant; Total phenolics
Engineering controlled terms: Essential oils; Phenols
Engineering main heading: Agents
Species Index: Achillea; Achillea millefolium;
Agrimonia; Agrimonia eupatoria; Eucalyptus; Eucalyptus globulus;
Hypericum; Hypericum androsaemum; Juglans; Juglans regia; Myrtus
communis; Rubus glaucus; Rubus idaeus; Salvia; Satureja montana; Thymus
vulgaris
