El-Helaly,, A. (2006). INFLUENCE OF INTERMITTENT WARMING ON REDUCING CHILLING INJURY AND KEEPING QUALITY OF ‘VALENCIA” . EXPORT ORANGES. Journal of Plant Production, 31(12), 7885-7901. doi: 10.21608/jpp.2006.236428
Amira A. E. El-Helaly,. "INFLUENCE OF INTERMITTENT WARMING ON REDUCING CHILLING INJURY AND KEEPING QUALITY OF ‘VALENCIA” . EXPORT ORANGES". Journal of Plant Production, 31, 12, 2006, 7885-7901. doi: 10.21608/jpp.2006.236428
El-Helaly,, A. (2006). 'INFLUENCE OF INTERMITTENT WARMING ON REDUCING CHILLING INJURY AND KEEPING QUALITY OF ‘VALENCIA” . EXPORT ORANGES', Journal of Plant Production, 31(12), pp. 7885-7901. doi: 10.21608/jpp.2006.236428
El-Helaly,, A. INFLUENCE OF INTERMITTENT WARMING ON REDUCING CHILLING INJURY AND KEEPING QUALITY OF ‘VALENCIA” . EXPORT ORANGES. Journal of Plant Production, 2006; 31(12): 7885-7901. doi: 10.21608/jpp.2006.236428
INFLUENCE OF INTERMITTENT WARMING ON REDUCING CHILLING INJURY AND KEEPING QUALITY OF ‘VALENCIA” . EXPORT ORANGES
Dunng 2004 and 2005 seasons, consignment of ValenciaN oranges was
obtained from citrus packinghouse before shipping to overseas markets. The fruits
were stored for up to 15 weeks at the following temperature regimes (a) Continuous
temperature at 5 oc (control), the remained fruits were subjected to intermittent
warming (1W) cycles of (b) 18 days[d] at 5°C + 36 hours[h] at 20°C; (c) 18 d at 5°C +
48h at 20°C; (d) 18d at 5°C + 60h at 20°C; (e) 18d at 5°C + 72h at 20°C; (f) 13d at
5°C + 24h at 20°C; (g) 6d at 5°C + 12h at 20°C and (h) 6d at 5°C + 24h at 20°C, with
RH 85-90%. AIl fruits then were held at 20°C with RH 80-90% for one week to
simulate re(ial marketing.
The results indicated that, in both experimental seasons, as the storage penod
advanced, the percentages of unmarketable fruits, weight loss, total soluble solids
(TSS) and TSS: acid ratio were significantly increased. Meanwhile, the percentages of
titratable acidity (TA), fruit juice (%) and values of ascorbic acid (V.C) significantly
decreased, as an average for ail treatments. The highest significant unmarketable
(%) existed ¡n fruits stored continuously at 5°C (control) (37.22 and 33.33% in first and
second season, respectively), compared with those in oranges treated with 1W
treatments (9.44- 24.44% in first season and 10.55 — 27.22% in the second), as an
average for all storage penods. In addition, dunng the following shelf life period, those
percentages were significantly decreased from 90% in both seasons in fruits stored
continuously at 5°C to 46.66 -73.33% and 40.00- 73.33% in first and second
seasons, respectively ¡n ones treated with intermittent warming treatments. Moreover,
1W had a great effect on decreasing fruit weight loss percentages.
The effectiveness of 1W treatments on improving physical properties, was not
clea1y noticed on chemical ones such as TSS, TA, fruit juice (%), TSS: TA and V.C
content. In spite of the efficiency of 1W on TA was not clearly obvious, it was found
that fruits treated with long cycle 1W treatments (b),(c), (d) and (e) showed highest
percentages followed by medium one (f) then those of short cycles (g) and (h).
The best 1W treatment was (g) (6d at 5°C + 12h at 20°C) as the most clear
reduction in unmarketable fruits (%)associated with that treatment especiaIy during
storage period, while the worst one was (f) (13 d at 5°C + 24h at 20°C) whereas the
rest of 1W treatments showed medium effects. Generally, there were no significant
differences among long cycles intermittent warming treatments (b), (C), (d) and (e) on
reducing the percentages of unmarketabe fruits and weight loss. Also between short
cycles 1W treatments (g) and (h) on reducing weight loss.
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