Abstract:
The effect of some factors that can affect quality characteristics of broccoli
florets in storage was evaluated. Quality characteristics of broccoli florets with
different rates of field nitrogen (N) application (0, 90, 180, and 270 Kg N/ha from
urea) were evaluated in modified atmosphere packaging (MAP) (B-900 Cryovac
film) storage at 0°C. Increased field N application resulted in more green color
and higher chlorophyll concentration but these differences disappeared as
chlorophyll linearly decreased by 50% during 28 days of MAP storage. N
fertilization up to 180 Kg/ha increased ascorbic acid content at harvest but losses
in storage were not affected by nitrogen fertilization treatments. It was noted in
several of the packages with B-900 film that off-odors were present after storage.
While this was noted late in the evaluation (not quantified) this led to a second
experiment.
MAP using three Cryovac polyolefin films (PD-941, PD-961EZ, and PD-
900) and perforated polyethylene bags were evaluated for broccoli florets stored
at 0°, 5°, and 10°C. Films with differential permeability properties had similar
effects on controlling weight loss but significantly affected in-package CO₂ and
O₂ concentrations. Color (Hue angle and Chroma) and chlorophyll retention was
better in MAP broccoli florets than perforated bag controls. MAP also delayed
loss of ascorbic acid. The beneficial effects of MAP were especially noticeable
when the florets were stored at 5° and 10°C in which shelf life was appreciably
extended. Broccoli florets in PD-941 film developed no off-odors during 28 days
storage even under the highest (10°C) storage temperature.
Seven different broccoli cultivars were evaluated for quality in MAP
storage using Cryovac PD-941 film. Weight loss was kept very low (less than
3%) during 21 days at 4°C and even 5 days after transfer to 15°C storage room.
Differences in ascorbic acid content, chlorophyll concentration and green
coloration were found among cultivars. While these quality characteristics
differed greatly between cultivars at harvest, they lost them at different rates in
storage. From this study, 'ATX91-307' followed by 'Emerald' appeared to be
superior to the others during simulated marketing conditions of 21 days at 4°C
plus 5 days at 15°C under near optimal MAP conditions.
