March 17/Werribee, Australia/Food Weekly News -- "Physical properties of stirred yogurt made from reconstituted skim milk that was high-pressure (HP) treated at 100, 250 or 400MPa, at 25, 70 or 90 degrees C, for 10 minutes, prior to inoculation with yogurt cultures, were studied; portions of milk HP-treated at 25 degrees C were also heat-treated at 90 degrees C for 10 minutes before or after pressure treatment. Control yogurts were made from skim milk given a heat treatment at 90 degrees C for 10 minutes," scientists in Werribee, Australia, report.
"Fermentation time was not affected by treatment applied to the milk. HP treatment of skim milk at 25 degrees C, before or after heat treatment, gave stirred yogurts of similar viscosities to that made from conventionally heat-treated milk. Lower viscosities were obtained when stirred yogurts were made with milk HP-treated at elevated temperatures. A model is proposed to correlate properties of yogurt with HP/heat-induced changes in interactions and structures of protein in the milk samples. Industrial relevance: To meet end user expectations, the dairy industry needs to diversify its product range by tailoring specific functionalities. To meet these expectations, new processing methods such as high-pressure processing are of interest for their potential to achieve specific and/or novel functionalities and/or improve efficiencies, including reduced chemical and water use," wrote P. Udabage and colleagues.
Udabage and colleagues published their study in Innovative Food Science & Emerging Technologies ("Properties of Low-fat Stirred Yogurts Made from High-pressure-processed Skim Milk." Innovative Food Science & Emerging Technologies,/i>, 2010;11(1):32-38).
For more information, contact P. Udabage, CSIRO Food & Nutr Science, 671 Sneydes Rd, Werribee, Vic 3030, Australia.
From the March 29, 2010, Prepared Foods E-dition