Free Access
Volume 80, Number 1, January-February 2000
New applications of membrane technology in the dairy industry
Page(s) 15 - 23
DOI: 10.1051/lait:2000102

Lait 80 (2000) 15-23

UHT processed milk concentrates

Jörg Hinrichs

Chair for food process engineering, Technische Universität München, 85350 Freising-Weihenstephan, Germany


Ultrafiltration and reverse osmosis concentrates made from milk with differing fat and protein contents were sheared in defined flow conditions to establish the critical concentration of the constituents beyond which flow properties and heat stability change. The viscosity of the concentrates at $20~^\circ$C was calculated for volume concentrations below 0.5. Non-Newtonian flow occurred above this concentration, and heat coagulation tests at $140~^\circ$C revealed a dramatic drop in heat stability. The dense packing of the constituents above a volume concentration of 0.5 led to altered flow properties and decreased heat stability. The heat stability at $140~^\circ$C and storage stability correlated with the ash content and these increase as the ash contents decrease. Milk may be treated by applying ultrafiltration and nanofiltration to reduce ash content and enable high quality milk concentrates with a long-life stability to be produced by means of ultra-high temperature heating.

milk / ultrafiltration / nanofiltration / rheology / ultra-high temperature

Correspondence and reprints: J. Hinrichs

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