Journal article
The effects of microfluidization on the physical, microbial, chemical, and coagulation properties of milk
Journal of dairy science, v 101(8), pp 6990-7001
01 Aug 2018
PMID: 29778477
Abstract
This work examines the use of mild heat treatments in conjunction with 2-pass microfluidization to generate cheese milk for potential use in soft cheeses, such as Queso Fresco. Raw, thermized, and high temperature, short time pasteurized milk samples, standardized to the 3% (wt/wt) fat content used in cheesemaking, were processed at 4 inlet temperature and pressure conditions: 42 degrees C/75 MPa, 42 degrees C/125 MPa, 54 degrees C/125 MPa, and 54 degrees C/170 MPa. Processing-induced changes in the physical, chemical, and microbial properties resulting from the intense pressure, shear, and cavitation that milk experiences as it is microfluidized were compared with nonmicrofluidized controls. A pressure-dependent increase in exit temperature was observed for all microfluidized samples, with inactivation of alkaline phosphatase in raw and thermized samples at 125 and 170 MPa. Microfluidization of all samples under the 4 inlet temperature and processing pressure conditions resulted in a stable emulsion of fat droplets ranging from 0.390 to 0.501 mu m, compared with 7.921 (control) and 4.127 (homogenized control) mu m. Confocal imaging showed coalescence of scattered fat agglomerates 1 to 3 mu m in size during the first 24 h. We found no changes in fat, lactose, ash content or pH, indicating the major components of milk remained unaffected by microfluidization. However, the apparent protein content was reduced from 3.1 to 2.2%, likely a result of near infrared spectroscopy improperly identifying the micellar fragments embedded into the fat droplets. Microbiology results indicated a decrease in mesophilic aerobic and psychrophilic milk microflora with increasing temperature and pressure, suggesting that microfluidization may eliminate bacteria. The viscosities of milk samples were similar but tended to be higher after treatment at 54 degrees C and 125 or 170 MPa. These samples exhibited the longest coagulation times and the weakest gel firmness, indicating that formation of the casein matrix, a critical step in the production of cheese, was affected. Low temperature and pressure (42 degrees C/75 MPa) exhibited similar coagulation properties to controls. The results suggest that microfluidization at lower pressures may be used to manufacture high-moisture cheese with altered texture whereas higher pressures may result in novel dairy ingredients.
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Details
- Title
- The effects of microfluidization on the physical, microbial, chemical, and coagulation properties of milk
- Creators
- A. J. Bucci - Eastern Regional Research CenterD. L. Van Hekken - Eastern Regional Research CenterM. H. Tunick - Agricultural Research ServiceJ. A. Renye - Eastern Regional Research CenterP. M. Tomasula - Eastern Regional Research Center
- Publication Details
- Journal of dairy science, v 101(8), pp 6990-7001
- Publisher
- Elsevier
- Number of pages
- 12
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Food and Hospitality Management
- Web of Science ID
- WOS:000439134700027
- Scopus ID
- 2-s2.0-85047225224
- Other Identifier
- 991021920649304721
InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Agriculture, Dairy & Animal Science
- Food Science & Technology