INVESTIGADORES
ROJAS Ana Maria Luisa
artículos
Título:
Effects of gamma irradiation on bio-chemical and physico-chemical parameters of fresh-cut red beet (Beta vulgaris L. var. conditiva) root.
Autor/es:
LATORRE M. E.; NARVAIZ P.; ROJAS A. M.; GERSCHENSON L. N.
Revista:
JOURNAL OF FOOD ENGINEERING
Editorial:
ELSEVIER SCI LTD
Referencias:
Lugar: Oxford, UK.; Año: 2010 vol. 98 p. 178 - 191
ISSN:
0260-8774
Resumen:
Red beet (Beta vulgaris L. var. conditiva) root is a popular item present in ready to eat salads and minimally
processed foods. In this research, the effect of low doses of gamma radiation (1 and 2 kGy) on peroxidase
(POX), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities, as well as on
the levels of compounds related to the response to the oxidative stress of plant metabolism, the changes
in colour and the mechanical behaviour of fresh-cut red beet root were analyzed, with the purpose of
understanding the influence of the processing on tissue characteristics. Cell wall modifications were also
studied through sequential extractions of polysaccharides from the alcohol-insoluble residues (AIR)
obtained from each tissue. Irradiation seemed to contribute to higher cellcell adhesion through increasing
of calcium-cross linking at the middle lamellae regions, in addition to an increment of cross-links of
polymers into the cell wall. Chemical modifications produced in the cell walls as a response to higher levels
of H2O2 and subsequent POX mediated effects, were visualized structurally as a more elastic behaviour
of irradiated tissues and rigidification of cell walls of treated roots, though puncture test did not
reveal significant differences. Microscopy showed a continuum of thick cell walls in beet root tissue,
which suffered slight modifications after irradiation, coherent with the bio-chemical results obtained.
It can be concluded that irradiation doses of 1 or 2 kGy produced bio-chemical changes in cellular contents
as well as in the cell wall constitutive networks which not necessarily could be sensed by consumers
as it was objectively evaluated through a puncture test. At the same time, the mentioned changes
involved an increase in the antioxidant capacity of red beet root tissue, showing that studied doses could
be interesting to be used in the frame of a combined technique for red beet processing.Beta vulgaris L. var. conditiva) root is a popular item present in ready to eat salads and minimally
processed foods. In this research, the effect of low doses of gamma radiation (1 and 2 kGy) on peroxidase
(POX), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities, as well as on
the levels of compounds related to the response to the oxidative stress of plant metabolism, the changes
in colour and the mechanical behaviour of fresh-cut red beet root were analyzed, with the purpose of
understanding the influence of the processing on tissue characteristics. Cell wall modifications were also
studied through sequential extractions of polysaccharides from the alcohol-insoluble residues (AIR)
obtained from each tissue. Irradiation seemed to contribute to higher cellcell adhesion through increasing
of calcium-cross linking at the middle lamellae regions, in addition to an increment of cross-links of
polymers into the cell wall. Chemical modifications produced in the cell walls as a response to higher levels
of H2O2 and subsequent POX mediated effects, were visualized structurally as a more elastic behaviour
of irradiated tissues and rigidification of cell walls of treated roots, though puncture test did not
reveal significant differences. Microscopy showed a continuum of thick cell walls in beet root tissue,
which suffered slight modifications after irradiation, coherent with the bio-chemical results obtained.
It can be concluded that irradiation doses of 1 or 2 kGy produced bio-chemical changes in cellular contents
as well as in the cell wall constitutive networks which not necessarily could be sensed by consumers
as it was objectively evaluated through a puncture test. At the same time, the mentioned changes
involved an increase in the antioxidant capacity of red beet root tissue, showing that studied doses could
be interesting to be used in the frame of a combined technique for red beet processing.2O2 and subsequent POX mediated effects, were visualized structurally as a more elastic behaviour
of irradiated tissues and rigidification of cell walls of treated roots, though puncture test did not
reveal significant differences. Microscopy showed a continuum of thick cell walls in beet root tissue,
which suffered slight modifications after irradiation, coherent with the bio-chemical results obtained.
It can be concluded that irradiation doses of 1 or 2 kGy produced bio-chemical changes in cellular contents
as well as in the cell wall constitutive networks which not necessarily could be sensed by consumers
as it was objectively evaluated through a puncture test. At the same time, the mentioned changes
involved an increase in the antioxidant capacity of red beet root tissue, showing that studied doses could
be interesting to be used in the frame of a combined technique for red beet processing.