PROBIEN   20416
INSTITUTO DE INVESTIGACION Y DESARROLLO EN INGENIERIA DE PROCESOS, BIOTECNOLOGIA Y ENERGIAS ALTERNATIVAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Effect of pulsed light and ascorbic acid/CaCl2 dipping on rheological properties of fresh-cut apples
Autor/es:
GÓMEZ, PAULA; SALVATORI, DANIELA; ALZAMORA, STELLA M.
Lugar:
Atenas
Reunión:
Congreso; XI ICEF International Congress on Engineering and Food; 2011
Resumen:
The aim of this work was to evaluate the changes on linear viscoelastic properties of fresh-cut apples
irradiated with pulsed light (PL) subjected or not to an antibrowning pretreatment. Apple slices (3 cm
diameter and 0.6 cm thickness) were dipped into a 1% (w/v) ascorbic acid + 0.1 % (w/v) calcium chloride
solution for 5 min at 4ºC. The PL treatments were performed with a RS-3000B Steripulse-XL system, which
produced polychromatic radiation (200 to 1100 nm) and generated high intensity pulsed light. Samples were
exposed to irradiation for 60 s at 10 cm from the lamp (fluence: 72 J/cm2). Slices irradiated with and without
the antibrowning pretreatment were compared to a control throughout a week of storage at 4-5ºC. Dynamic
oscillatory shear and creep/recovery tests were performed at 0 and 7 day. Creep behavior was fitted with a
mechanical model (a spring, two Kelvin-Voigt elements and a dashpot). Light microscopy observations were
made after processing and storage. Storage moduli (G?) of apples exposed to PL were lower than those of the
fresh fruit, both at 0 and 7 day. The decrease was more pronounced when apples were pretreated with the
antibrowning solution. The instantaneous compliance (J0) and the retarded compliance (J2) increased after 7
day storage in samples irradiated, denoting that these tissues became more deformed. The changes in
compliances were greater in irradiated samples previously dipped into the antibrowning solution. Rheological
response of apple tissue was correlated with microstructure and ultrastructure features. Pulsed light at the
dose tested induced changes in viscoelastic properties of apple tissue that led to both a loss of stiffness and
higher capacitance values. These changes were increased by ascorbic acid/CaCl2 treatment and during
storage. However, due to the fact that PL irradiation has low penetration, changes in viscoelasticity would be
given mainly in superficial region of irradiated samples.