US3977945A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Time and temperature-dependent enzymatic indicator
Assignee: Food Control AB
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Filing: 1975-02-20
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Granted: 1976-08-31
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Expires: 1995-02-20
Abstract
Abstract A time and temperature dependent enzymatic indicator with discontinuable indication comprises a plastic envelope container enclosing an enzyme, an enzymatic substrate and a pH-indicator as active components, the indication being discontinuable in that the enzyme is bound to a carrier and in that the plastic envelope is sealable for dividing the container into two compartments, one of which is free from enzyme and thus cannot provide further indication.
Inventors
- 👤 Sven Ivan Arvid Tornmarck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:12
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/02; G01N31/00; G01N31/22; G01N31/229
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
156 words
In a time and temperature-dependent enzymatic indicating device for indicating the storage conditions of storage-sensitive perishable products comprising an aqueous liquid containing an enzyme, a substrate capable of being acted on by said enzyme to produce reaction products, and a pH indicating substance which changes color for indicating a change in pH resulting from action of said enzyme on the substrate, said aqueous liquid being enclosed in a surrounding plastic envelope having opposed inner surfaces, the improvement comprising the time and temperature-dependent enzymatic indicating device being operable to stop color change of said pH indicating substance by having the enzyme bound to a solid carrier and having the opposed inner surfaces of said surrounding plastic envelope comprise a layer of a material which is sealable by means of pressure whereby said indicating device is divisible into separate compartments including at least one compartment free from enzyme wherein further change of said indicating substance can not continue.
Claim 2
Dependent Claim
156 words
In a time and temperature-dependent enzymatic indicating device for indicating the storage conditions of storage-sensitive perishable products comprising an aqueous liquid containing an enzyme, a substrate capable of being acted on by said enzyme to produce reaction products, and a pH indicating substance which changes color for indicating a change in pH resulting from action of said enzyme on the substrate, said aqueous liquid being enclosed in a surrounding plastic envelope having opposed inner surfaces, the improvement comprising the time and temperature-dependent enzymatic indicating device being operable to stop color change of said pH indicating substance by having the enzyme bound to a solid carrier and having the opposed inner surfaces of said surrounding plastic envelope comprise a layer of a material which is sealable by means of pressure whereby said indicating device is divisible into separate compartments including at least one compartment free from enzyme wherein further change of said indicating substance can not continue.
Claim 3
Dependent Claim
53 words
The indicating device according to claim 1, characterized by the fact that said enzyme is initially disposed in a first compartment, while said substrate and said pH indicating substance are initially disposed in another compartment, said compartments being separated by means of a frangible seal interconnecting the opposite walls of said plastic envelope.
Claim 4
Dependent Claim
17 words
The indicating device according to claim 1, characterized by the fact that said enzyme is pancreas lipase.
Claim 5
Dependent Claim
16 words
The indicating device according to claim 1, characterized by the fact that said carrier is nylon.
Claim 6
Dependent Claim
23 words
The indicating device according to claim 1, characterized by the fact that said enzyme is bound to said carrier by means of glutaraldehyde.
Claim 7
Dependent Claim
16 words
The indicating device according to claim 1, characterized by the fact that said substrate is tricaproin.
Claim 8
Dependent Claim
38 words
The indicating device according to claim 1, characterized by the fact that said plastic envelope consists of a three-layer plastic sheeting comprising one layeer of polyester, one layer of polyvinylidene chloride, and one layer of low density polyethylene.
Claim 9
Dependent Claim
34 words
The indicating device according to claim 1, characterized by the fact that said plastic envelope consists of a two-layer plastic sheeting comprising one layer of polyvinylidene chloride and one layer of high density polyethylene.
Claim 10
Dependent Claim
21 words
The indicating device according to claim 1, characterized by the fact that said plastic envelope consists of fluorinated hydrocarbon polymer sheeting.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-31 | 1980-03-01 | 1980-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-31 | 1984-03-01 | 1984-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-31 | 1988-03-01 | 1988-08-31 | $7700.00 | Window Closed / Lapsed |