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Abstract
O2 at 1% or less inhibited yellowing of broccoli curds during storage at 5° or 7.5°C and the effect persisted during 2 or 3 days' subsequent aeration at 10°. Yellowing was minimal at 2.5°, regardless of O2 concn. Odor and flavor of cooked curds were best in samples from 1/2 or 1% O2, but 1/4% O2 or less impaired odor and flavor. Visible low-O2 injury developed in 1/10% O2.
CO2 at 10% also retarded yellowing, and off-odors induced by CO2 disappeared upon cooking.
Low O2 did not affect shear resistance (SR) of the cooked curd, but 10% CO2 softened the tissue. With or without CO2, log SR (kg) and pH were linearly and inversely related.
For broccoli shipped over long distances or stored prior to processing, lowering O2 to 1/2 to 1% and/or increasing CO2 to 10% would materially help in retarding deterioration when temp cannot be maintained near 0°C.
Abstract
Cauliflower curds stored up to 3 weeks at 2.5, 5, or 7.5°C in atmospheres with 2, 4, or 6% O2 were not superior to curds stored in air. Curds stored in 1% O2 almost always developed off-odors and off-flavors when cooked; those stored in 2% O2 occasionally showed this response. Visible injury developed in 1% O2. This level of O2 also favored soft rot. Oxygen concentration did not significantly affect the color, firmness or pH of the tissue. The effects of low O2 on cauliflower are contrasted with those obtained earlier with broccoli. A hypothesis is proposed that holds that the difference in sensitivity of these and other closely related vegetables to low O2 and high CO2 is related to the presence of chlorophyll in the tissue.
Abstract
The tolerance of six cultivars of nectarine [Prunus persica (L.) Batsch var. nectarina (Ait.) Maxim.] to methyl bromide (MB) quarantine treatments was determined. A treatment, 48 g MB/m3 for 2 hr at 21C, which controlled codling moth [Cydia pomonella (L.)], caused no significant phytotoxic response in any of the cultivars. The threshold for injury at the above time and temperature was ≈64 g MB/m3 in ‘Summer Grand’, ‘May Grand’, ‘Fantasia’, and ‘Firebrite’; between 48 and 64 g MB/m3 in ‘Red Diamond’; and between 80 and 96 g MB/m3 in ‘Spring Red’. All fumigated nectarines were significantly firmer than the control fruit after storage for 7 days at 2.5C, but subsequently ripened satisfactorily; soluble solids content of the fruit was not affected by the fumigations used in this study. Inorganic bromide residues in fruit treated with the 48 g·m−3 dosage at 21C or above ranged from 3.5 to 7.2 ppm, well below the U.S. tolerance of 20 ppm. Organic bromide residues were <0.01 ppm within 48 hr after treatment.