4. Conclusions
The effectiveness of the astringency removal treatment with
CO2 under standard conditions diminished the longer the fruit
was stored at 15 ◦C. In the present study, a loss of effectiveness
was observed when the treatment was applied after more
than 20 d of storage. The phenomenon may be explainable by
the structural changes at the cell level that the flesh undergoes
during storage at that temperature. Thus, as storage at 15 ◦C is
prolonged, the initial cell structure of the flesh becomes more
and more degraded and the intercellular spaces are progressively
filled by cell material. Diffusion of CO2 through the spaces is
made more difficult; the result is a low rate of anaerobic respiration
and consequently less accumulation of acetaldehyde. This,
in turn, leads to a lesser reduction of the soluble tannins that are
responsible for the astringency of the fruit. However, when the
CO2 treatment was applied prior to storage, a less degraded cell
structure, with more empty intercellular spaces, allows the CO2
to diffuse and anaerobic respiration is activated correctly. The
result is an effective treatment.
From the present research, therefore, when ‘Rojo Brillante’
persimmons are stored for periods of 30 d at 15 ◦C, applying a
CO2 treatment prior to storage presents definite advantages over
a post-storage treatment. It ensures not only that the treatment
will be the most effective, but also that the firmness values of
the fruit after shelf-life simulation will, nevertheless, be similar
to those that prevail when the treatment is applied after storage.