http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Effect of homogenization pressure and whey protein source on rheological properties of heat-set whey protein emulsion gels
Emulsions with 10% protein and 20% butter oil were prepared by dispersing sweet whey protein concentrate (SWPC), acid whey protein concentrate (AWPC), or AWPC + glycomacropeptide (GMP) in distilled water with butteroil. The mixture was heated to 65⁰C and homogenized at 20 and 90 MPa. Whey protein emulsions were heated to 90⁰C for 30 min in a closed water bath to form gels. The d[vs] of particles in the emulsions made from sweet whey was lower (p<0.05) than the d[vs] of particles in the emulsions made from AWPC and AWPC + GMP. The d[vs] of particles in emulsions made using AWPC was not different (p>0.05) from d[vs] of particles in emulsions prepared from AWPC + GMP. The distribution of particles sizes in WPC emulsions homogenized at 90 MPa was bimodal distribution compared to emulsions homogenized at 20 MPa. The surface area of particles in SWPC emulsions increased 2.5x when the homogenization pressure was increased from 20 to 90 MPa. However, the surface area of emulsions prepared from AWPC and AWPC + GMP homogenized at 20 MPa decreased 5x when homogenized at 90 MPa. Gels made using AWPC and AWPC + GMP emulsions had a higher shear stress at fracture than gels made using SWPC. The shear stress at fracture of gels made using AWPC and AWPC + GMP and homogenized at 20 MPa were 13.48 kPa and 15.06 kPa but increased to 23.81 kPa and 22.07 kPa, respectively, when the emulsions were homogenized at 90 MPa. The shear strain at fracture of gels made using the AWPC and AWPC + GMP emulsion homogenized at 20 MPa were 1.1 and 1.12 and decreased to 0.75 and 0.71, respectively when the emulsions were homogenized at 90 MPa. The shear stress and strain at fracture for gels containing AWPC + GMP was similar to the shear stress and strain value at fracture for gels made from AWPC. Gels made using SWPC emulsions exhibited the most true shear strain (p<0.05) and had a more rubbery texture than gels made from AWPC and AWPC + GMP emulsions which had a lower true shear strain value and a brittle texture.
"Major subject: Food Science and Technology".
Issued also on microfiche from Lange Micrographics.
Includes bibliographical references (leaves 67-73).