Uso della fluorescenza della clorofilla a per valutare la qualità della lattuga da IV gamma conservata in atmosfera controllata
Articolo
Data di Pubblicazione:
2010
Citazione:
Uso della fluorescenza della clorofilla a per valutare la qualità della lattuga da IV gamma conservata in atmosfera controllata / V. Baldassarre, A. Spinardi, G. Cocetta, L. Martinetti, I. Mignani, A. Ferrante. - In: ITALUS HORTUS. - ISSN 1127-3496. - 17:3(2010), pp. 93-98.
Abstract:
The leafy vegetables used for minimally
processed products have a limited shelf life usually 5-
6 days. The quality of the vegetables is generally represented
by antioxidant compounds, vitamins and leaf
pigments that all together contribute to the aesthetical
and nutritional quality. During storage the quality
declines and atmosphere modification inside packaging
such as oxygen reduction and carbon dioxide
increase can be used for slowing down the degenerative
processes. The aim of this work was to monitor
the chlorophyll a fluorescence parameters during storage
and evaluate if this non destructive system might
be used for monitoring the quality of product during
postharvest stage. Among the chemical compound
the ascorbic acid has been determined.
Lettuce baby leaf (Lactuca sativa L.) was harvested
and processed following the industry procedures.
Lettuce was packed and stored at 4 °C with air or with
a modified atmosphere packaging (MAP). The oxygen
concentration in MAP was lowered to 13-14%.
During storage the ascorbic acid rapidly declined during
storage in the control and MAP bags. The reduction
was stronger in lettuce stored in MAP. At beginning
of experiment the ascorbic acid was 12 mg/ 100
g p.f., after 3 days the higher values was found in normal
atmosphere 2 mg/100 g p.f. while in MAP stored
lettuce the ascorbic acid was very low almost 0. The
chlorophyll a fluorescence progressively decreased
with storage time and in MAP the reduction was faster
showing lower values of all parameters measured.
The Fv/Fm ratio declined until to reach 0.64 at 4 °C
and 0.68 at 8 °C in MAP, while in control leaves the
values at both storage temperatures were 0.83-0.84
and did not statistically decrease during storage. The
Fo increased during storage and higher values were
observed in lettuce stored in MAP. The Fm values
declined in MAP at both storage temperatures after 6
days. The JIP test performed on the intermediate
points of induction curves showed that the energy
absorbed per cross section (ABS/CS) and the dissipation energy per cross section (DIo/CS) increased in
MAP stored leaves. On the contrary, the electron flux
per cross section, the density of active reaction centres
per cross section (RC/CSm) and the performance
index (PI) drastically decreased in MAP. The PI after
6 days strongly declined in leaves stored under MAP,
reaching values close to 0.
In conclusion, data obtained suggest that lettuce
stored under MAP was more stressed than in normal
atmosphere.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Ascorbic acid ; baby leaf ; fluorescence ;
fresh-cut ; storage
Elenco autori:
V. Baldassarre, A. Spinardi, G. Cocetta, L. Martinetti, I. Mignani, A. Ferrante
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