Organic compounds -- part of the class 532-570 series – Organic compounds – Carbohydrates or derivatives
Reexamination Certificate
1999-04-01
2001-05-22
Tentoni, Leo B. (Department: 1732)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbohydrates or derivatives
C264S140000, C536S099000
Reexamination Certificate
active
06235893
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a cellulose ether having enhanced gel strength and a process for making.
BACKGROUND OF THE INVENTION
Cellulose ethers have been employed as additives to food compositions and processes to provide physical properties such as thickening, freeze/thaw stability, lubricity, moisture retention and release, film formation, texture, consistency, shape retention, emulsification, binding, suspension, and gelation.
A physical property important in some food compositions is gel strength or elastic modulus. This property relates to the strength with which a cellulose ether binds or holds food particles together. Efforts to significantly increase gel strength for conventional cellulose ethers beyond levels observed for given viscosity grades have been largely unsuccessful.
Having a cellulose ether which exhibits enhanced gel strength for given viscosity grades would enable food compositions with superior binding, consistency, and shape retention to be developed. Also, viscosity contribution and cellulose ether concentrations could be reduced in food compositions while maintaining desired gel functionality.
It would be desirable to have a cellulose ether which exhibits elevated gel strength for a given molecular weight or viscosity grade. It would also be desirable to have a process for making the cellulose ether.
SUMMARY OF THE INVENTION
According to the present invention, there is a methylcellulose having a methoxy substitution of about 25 to about 42 percent based upon the weight of the cellulose ether and a viscosity (v) to elastic modulus (EM) relationship of EM≧181.3×(v
0.2711
). “≧” means “greater than or equal to.” Viscosity is for a 2 percent aqueous solution at 20° C. EM corresponds to gel strength.
Further according to the present invention, there is a process for making a cellulose ether. The process comprises the following: a) contacting a cellulose pulp with a first amount of aqueous alkaline hydroxide at reaction conditions sufficient to alkalize it to a first level of alkalization which is about 20 percent or more of a total level of alkalization; b) contacting the cellulose pulp of first level of alkalization with a first amount of a methylating agent at reaction conditions sufficient to form a cellulose ether having a first level of methoxy substitution which is about 20 percent or more of a total level of methoxy substitution; c) contacting the cellulose ether of first level of etherification with a second amount of aqueous alkaline hydroxide at reaction conditions sufficient to alkalize it to a second level of alkalization which is about 40 percent or more of the total level of alkalization; and d) continuously or incrementally contacting the cellulose ether of second level of alkalization with a second amount of a methylating agent over a period of time at reaction conditions sufficient to form a cellulose ether of the second level of methoxy substitution which is about 40 percent or more of the total level of methoxy substitution, the second amount of the methylating agent provides about 20 percent or more of the total level of methoxy substitution; the second amount of the methylating agent is contacted with the cellulose ether of second level of alkalization at about 65° C. to about 110° C. for 15 minutes or more.
Further according to the present invention, there is a food composition comprising a foodstuff and the present cellulose ether.
Further according to the present invention, there is a pharmaceutical capsule comprising the present cellulose ether.
REFERENCES:
patent: 2160782 (1939-05-01), Maasberg
patent: 2671779 (1954-03-01), Gaver et al.
patent: 4456751 (1984-06-01), Messelt et al.
patent: 4477657 (1984-10-01), Strange et al.
patent: 4661589 (1987-04-01), Adams et al.
patent: 5618800 (1997-04-01), Kabra et al.
patent: 1060374 (1959-07-01), None
Nitis Sarkar, “Structural interpretation of the interfacial properties of aqueous solution of methylcellulose and hydroxypropyl methylcellulose,”Polymer, vol. 25, Apr. 1984, p. 481-486.
Conklin Jerry R.
Reibert Kenneth C.
Tentoni Leo B.
The Dow Chemical Company
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