Warm (20C) or cold (3C) broccoli florets (Brassica oleracea L., Italica Group) were sealed in bags of two types of nonperforated flexible polyvinylchloride film, TPM 87 or RMF 61, and kept at 5C for 7 days. Temperature of the warm florets cooled to 5C in ≈ 8 hours. Warm broccoli had 40% to 50% more CO2 and 25% to 30% less O2 than cold broccoli in packages of both film types 6 hours after sealing. After 48 hours, however, concentrations of CO2 in bags of cold and warm broccoli had reached a steady state of ≈ 14.5% in TPM 87 bags and 6% in RMF 61 bags. Concentrations of O2 were more variable. After 48 hours, O2 concentrations were ≈ 2% to 4% in TPM 87 bags and 5% to 10% in RMF 61 bags. Initially, warm florets were rated lower for color, turgidity, and general appearance than initially cold ones after 7 days at 5C. Objectionable off-odors were formed from florets held in TPM 87 packages that had O2concentrations of <1.5%.
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