Keratin-based products and methods for their productions
AssigneeStichting Nederlands Instituut Voor Zuivelonderzoek
InventorsPeter Marcel Myriam Schrooyen, Radulf Oberthur
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Abstract
The present invention relates to a process for solubilizing keratins from a keratin containing starting material such as poultry feathers. The keratins are may be solubilized using a sulphide under alkaline conditions. In the process the cysteine residues of solubilized keratins and are partially modified, e.g. by alkylation. The conditions of solubilisation and partial modification are chosen such that the keratins are also partially hydrolyzed. The partially modified and partially hydrolyzed keratin may be used as stable dispersions e.g. for the production of films and coatings by casting.
Claims20
A process for producing partially modified and partially hydrolysed keratin, the process comprises the steps of (a) solubilising keratin from a keratin-fibre containing starting material in an aqueous solution using a reducing agent at an alkaline pH of between pH 10 and pH 13.5 and at a temperature of at least 40° C., and (b) partially modifying the —SH groups of the solubilised keratin by alkylation, characterised in that the solubilised keratin is partially hydrolysed as a result of the conditions of steps (a) and (b) and an optional further hydrolysis step (c), whereby the solubilised keratin is partially hydrolysed such that at least 50% of the solubilised keratin molecules has a molecular weight higher than 1 kDa and less than 10.4 kDa and whereby the solubilised keratin has molecular weight distribution that is equal to a distribution of molecular weights of keratin that is obtained when 40 grams of cleaned and dried poultry feathers are solubilised in one liter of an aqueous solution of 0.05–0.5 M sodium sulphide at a pH between pH 10.0 and pH 13.5, at a temperature between 40 and 80° C. for 30–90 minutes.
A composition comprising keratin, whereby the keratin is characterised in that:
- a) at least 10% and no more than 70% of the —SH groups of the keratin are modified by alkylation;
- and b) at least 50% solubilised keratin has a molecular weight of between 1 and 11 kDa and whereby the solubilised keratin has molecular weight distribution that is equal to a distribution of molecular weights of keratin that is obtained when 40 grams of cleaned and dried poultry feathers are solubilised in one liter of an aqueous solution of 0.05–0.5 M sodium sulphide at a pH between pH 10.0 and pH 13.5, at a temperature between 40 and 80° C. for 30–90 minutes.
A composition comprising keratin, whereby the composition is obtained in a process comprising the steps of:
- a) solubilising keratin from a keratin-fibre containing starting material in an aqueous solution of 0.05–0.5 M sodium sulphide at a pH between pH 10.0 and pH 13.5, at a temperature between 40 and 80° C. for 30–90 minutes;
- b) modifying between 10 and 70% of the —SH groups of the solubilised keratinby alkylation.
Dependencies are inferred from the claim text.