Biomedical Engineering Reference
In-Depth Information
changes. Irradiation also delayed senescence and reduced microbial spoilage of
grated carrots, which is of potential interest for the maintenance of shelf life of
minimally processed vegetables 255 and it has been reported 256 that irradiation was
superior to conventional methods for preservation of “ready to eat” shredded carrots.
Irradiation prevented losses of sugar,
-carotene, and orange color, inhibited aerobic
mesophilic and lactic microflora, gave improved sensory scores, and has been
reported to aid the preservation of fermented carrots. 257 Irradiation has been found
to be useful in the decontamination of several dehydrated vegetables, carrots, celery,
parsley, parsnips, and leeks. 258 A 5-kGy dose reduced initial microbial load by a
factor of 5 to 10, lending support to the usefulness of irradiation as a part of GMP
in the food industry. Cunha 259 found that the treatment of dried beans with gamma
radiation increased the hydration rate while decreasing cooking time and hardness
of the seeds, without affecting sensory properties. Delincee 260 reported that irradia-
tion of legumes at doses up to 1 kGy for the purpose of insect disinfestation will
not result in any adverse effects on cooking time, sensory quality, vitamin B content,
or protein quality of white beans, peas, and legumes. Onyenekwe and Ogbadu 261
reported successful elimination of the fungal population of dried red chilli peppers
with a dose of 7.5 kGy. Even radappertization at doses of 10 kGy did not produce
significant changes in capsaicin and carbohydrate, although there was a small
increase in oleoresin and lipid. Lescano et al. 262 reported that the shelf life of
asparagus spears was doubled when a dose of 2 kGy was used and there was no
significant differences in weight loss between control and irradiated samples.
Although shear force and acidity values were slightly higher in the irradiated sam-
ples, mesophilic bacteria, yeast, and molds were reduced 3 orders of magnitude on
treatment with 2 kGy. Irradiation at high doses has been reported to reduce aflatoxin
contamination in corn and peanuts (83% reduction at 20 kGy). 263
Mushrooms are the most promising product for using irradiation to delay mat-
uration. 264 A dose of approximately 1 kGy applied soon after picking at the closed
button stage prolonged shelf life at 10°C from 1 day to 5 to 6 days. In an earlier
study by Kovacs, 265 a panel of judges could not detect any changes in odor, flavor,
or texture of the irradiated mushrooms either immediately after treatment or during
storage. Minnaar and McGill 266 reported on the optimization of parameters for the
heat irradiation processing of mushrooms. Differences in texture, color, and viscosity
of the cream sauce were found between different replicates but not between different
temperature combinations (110, 115, and 120°C). The general appearance and color
of the products processed at 120°C were superior to those processed at 110°C. Use
of 120°C as the processing temperature resulted in the best product where a shorter
processing time is required to achieve commercial sterility (i.e., 28 min as compared
to 50 and 99 min at 115 and 110°C, respectively). The second phase of this study
investigated the heat and irradiation resistance of Clostridium sporogenes spores in
sliced mushrooms in cream and brine. 267 Gamma D 10 values for Clostridium spores
in cream sauce ranged from 3.1 to 4.0, whereas in brine the values ranged from
4.2 to 4.8. F 0 values for heating processes for mushroom in cream sauce and brine
were determined and the combined D 10 and F 0 values were used to propose possible
combination treatments. They found no significant differences in texture measurements
and sensory characteristics between treatments of heat-irradiation and irradiation-heat
β
Search WWH ::




Custom Search