A method of producing microparticles of the type having a crosslinked, aggregated protein matrix by spray drying

Abstract

A method of producing microparticles by spray drying comprises the steps of providing a spray-drying feedstock solution comprising water, a volatile divalent metal salt, weak acid, 5-15% dairy or vegetable protein (w/v) and 1-20% active agent (w/v). The feedstock solution is adjusted to have a pH at which the volatile divalent metal salt is substantially insoluble. The feedstock solution is then spray-dried at an elevated temperature to provide atomised droplets, whereby the volatile divalent metal salt disassociates at the elevated temperature to release divalent metal ions which crosslink and aggregate the protein in the atomised droplets to produce micro-particles having a crosslinked aggregated protein matrix and active agent dispersed throughout the matrix.

1 - 20 . (canceled) 
     
     
         21 . A spray-dried, food grade, microparticle having an active agent homogenously dispersed throughout a continuous dairy or vegetable protein matrix, in which the protein matrix comprises agglomerated and divalent metal ion crosslinked protein. 
     
     
         22 . A spray dried microparticle according to  claim 21  and comprising hydrocolloid, in which the active agent is homogenously dispersed throughout a continuous protein-hydrocolloid matrix. 
     
     
         23 . A spray dried microparticle according to  claim 22  in which the hydrocolloid comprises or consists of FOS. 
     
     
         24 . A spray dried microparticle according to  claim 22  in which the hydrocolloid comprises or consists of citrus fibre. 
     
     
         25 . A spray dried microparticle according to  claim 23  in which the hydrocolloid comprises or consists of FOS and citrus fibre, and in which the active agent is homogenously dispersed throughout a continuous protein-FOS-citrus fibre matrix. 
     
     
         26 . A spray dried microparticle according to  claim 21  having a dimension of 20-90 microns. 
     
     
         27 . A spray dried microparticle according to  claim 21  in which the active agent is a cell. 
     
     
         28 . A spray dried microparticle according to  claim 21  in which the active agent is a compound. 
     
     
         29 . A spray dried microparticle according to  claim 21  and comprising at least 50% active agent (w/w). 
     
     
         30 . A spray dried microparticle according to  claim 21  and comprising at least 70% active agent (w/w). 
     
     
         31 . A spray dried microparticle according to  claim 21  and comprising at least 80% active agent (w/w). 
     
     
         32 . A spray dried microparticle according to  claim 21  and comprising calcium hydroxymethyl butyrate. 
     
     
         33 . A spray dried microparticle according to  claim 21 , and produced by spray-drying according to a method of:
 providing a food-grade spray-drying feedstock solution comprising water, a volatile divalent metal salt, weak acid, 5-15% dairy or vegetable protein (w/v) and active agent (w/v), the feedstock solution having a pH at which the volatile divalent metal salt is substantially insoluble; and   spray drying the feedstock solution at an elevated temperature to provide atomised droplets whereby the volatile divalent metal salt disassociates at the elevated temperature to release divalent metal ions which crosslink and aggregate the protein in the atomised droplets to produce microparticles having a crosslinked aggregated protein matrix and active agent dispersed throughout the matrix.