| 摘要 |
Vegetables are preserved at low temp. in a closed package made of flexible thin film which is opaque to light and has w.r.t. gases low permeabilities such that:-Permeability to oxygen less than 5 cm3/m2/24 hr. (temp. = 23 deg.C, dry O2, pressure differential 1 atm); Permeability to CO2 less than 20 cm3/m2/24 hr. (temp. = 23 deg.C, dry CO2, pressure differential 1 atm); Permeability to water vapour less than 5 g/m2/24 hr., under tropical conditions (temp. = 38 deg.C, R.H. 90% (outside), 0% (inside). - Pref. the package has the following permeabilities at 0-10 deg.C:-Permeability to oxygen less than 1 cm3/m2/24 hr., Permeability to CO2 less than 5 cm3/m2/24 hr; Permeability to water vapour less than 0.5 g/m2/24 hr. - Pref. the package comprises a thin, opaque, single or complex thermoplastics film. A metallised thermoplastic film is pref. partic. a metallised film bonded to a second one. The thermoplastic film may be polyethylene.
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