Biomedical Engineering Reference
In-Depth Information
TABLE 3.5
Relationship Between Dosage (kGy) Causing
Quality Damage and Inhibiting Storage Rots
Max. Estimated
Max. Estimated Dose
Commodity
Tolerable Dose
Required for Control
Apricots
0.5
2.0
Boysenberries
1.0
2.0
Lemons/limes
0.25
1.5-2.0
Nectarines
1.0
2.0
Oranges
2.0
2.0
Peaches
1.0
2.0
Raspberries
1.0
2.0
Strawberries
2.0
2.0
Table grapes
0.25-0.5
10.0
Lu et al. 216 reported that treatment with UV radiation reduced storage rots in peaches
and apples. Flesh firmness of peaches and acidity of both fruits increased with dose,
while the percentage of soluble solids and pH decreased. Later work 217 confirmed
that both UV and gamma rays reduced storage rot and delayed ripening. However,
UV treated peaches contained less sugar, total phenolics, anthocyanins, and had a
lower weight loss than gamma irradiated peaches. Tsang 218 has reported that irradi-
ation of peaches at 1.0 kGy improved ripening and red color development, with
minor changes in aroma, flavor, and texture. This dose was found to inactivate a
population of brown rot by 2 D but also significantly decrease ascorbic acid. Lester 219
reported the successful irradiation of muskmelons at a dose of 1.0 kGy, prior to
storage to slow down the progression of senescence. Pirouzmand 220 reported the use
of irradiation for the deinfestation of larvae in apples at a dose of 1.2 kGy. This
decreased emergence of adult codling moths where there was minimal change in
texture of the fruit. Use of irradiation for insect disinfestation is more promising
than shelf-life extension, especially where fumigants formerly used have been
banned, like EDB. 215 Another promising use of irradiation is for the quarantine
treatment of imported produce. The process has been approved for insect disinfes-
tation in the U.S. since 1998 for doses up to 1 kGy. Fruits such as apples, cherries,
dates, guavas, mangos, nectarines, papayas, peaches, raspberries, strawberries, and
tomatoes suffer little phytotoxic damage at this dose. Comparisons of the effects of
irradiation and methyl bromide fumigation 221 have been carried out on Egyptian
semi-dried date fruits used for the manufacture of date paste. Irradiation at 3.0 kGy
was more effective for preventing insect infestation of the dates and inhibiting the
growth of fungi and thus preventing aflatoxin production.
Yu , 222,223 who reported that electron beam radiation can be used to extend the
shelf life of strawberries, found that fruit firmness and red color decreased, but an
off-flavor increased as the radiation dose increased from 0 to 2 kGy. However,
irradiation at these levels did suppress fungal growth leading to an extension of shelf
life by 2 to 4 days. Recent work by Cumming 224 using gamma irradiation also
 
 
Search WWH ::




Custom Search