Manufacture of and uses for low molecular weight agars and agaroids

US6322814A · kind A · utility

Inventor

• Ian Miller · Lower Hutt, NZ

Key dates

• Filing date: Nov 29, 1999
• Grant date: Nov 27, 2001
• Expiry date: Nov 29, 2019

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A23G2200/06
• WIPO field: Pharmaceuticals
• WIPO sector: Chemistry

Abstract

A process is claimed whereby an aqueous solution of agar, in which most (ideally all) 4-linked residues consist of 3,6-anhydro-L-galactose, is subjected to partial acid hydolysis and upon neutralization following the time appropriate for the chosen conditions, a low strength gel is obtained, from which, contrary to expectations, a polyagarobiose can be obtained by freeze-thawing and straining, thereby eliminating undesirable agaroid materials without the appropriate 3,6-anhydrogalactosyl content. The appropriate time of hydrolysis depends on initial gel strength, pH, counterion concentration and temperature. As an example, agar (gel strength 700 g/cm.sup.2, made to 1.86% solution) pH 3.25, counterion citrate (360 mg/L) at 96.degree. C. requires 25 minutes to yield a material with an eventual gel stregth (1.5% solution) of 40 g/cm.sup.2. A stabilized product can be prepared by reducing terminal anhydrogalactosyl residues with sodium borohydride. The resultant products are useful for preparing gels for application to the skin, such as massage gels, as skin moisturizers, or as carriers of other active ingredients, such as pharmaceuticals able to be applied through the skin.