Location: Dairy and Functional Foods
Title: Impact of high pressure processing on the quality traits of starter-free Queso Fresco Authors
Submitted to: International Dairy Federation Seminar
Publication Type: Abstract Only
Publication Acceptance Date: December 15, 2011
Publication Date: N/A
Technical Abstract: Queso Fresco (QF), a popular high-moisture, high-pH Hispanic cheese sold in the U.S., underwent high- pressure processing (HPP) to determine if this process, which has the potential to improve the safety of cheese, would alter its quality traits. Starter-free rennet-set QF (manufactured from pasteurized, homogenized milk, milled prior to hooping and chilled for 12 hours at 4 deg C) was cut into 4.5 X 4.5 X 15 cm3 blocks, and double vacuum packaged. Initially, blocks were warmed to either 22 or 40 deg C prior to HPP at 200, 400, or 600 MPa for 0, 5, 10, or 20 minutes and stored at 4 deg C until quality traits were measured within one week of manufacture. In the next phase, blocks were warmed to 22 deg C, subjected to HPP at 600 MPa for 0, 3, or 10 minutes, and stored at 4 or 10 deg C until quality traits were determined at weeks 1, 4, 8 and 12. HPP did not significantly affect the non-melt or color properties of QF. The amount of whey that accumulated in the package increased when QF was warmed to 40 deg C prior to HPP, as the pressure and length of processing increased, and as the storage time and temperature increased. HPP resulted in harder and less chewy cheese and the microstructure was compressed in appearance relative to the controls. Over the 12 weeks of storage, the viscoelastic traits of the cheese increased slightly with minor changes noted in texture profile and torsion analyses properties. QF remained a bright white, weak body cheese that crumbled and did not melt upon heating. Although high pressures or long processing times may be required for elimination of pathogens, HPP is not recommended for use with this non-pressed, high-moisture cheese because of the significant accumulation of whey in the package following processing.