14A-28

D. L. VAN HEKKEN¹, M. H. Tunick¹, K. A. Soryal², and S. S. Zeng². (1) Dairy Processing & Products Research Unit, USDA-ARS-Eastern Regional Research Center, 600 E. Mermaid Ln., Wyndmoor, PA 19038-8598, (2) E (Kika) de la Garza Institute for Goat Research, Langston Univ., Agricultural Research & Extension Programs, PO Box 730, Langston, OK 73050-0730

The manufacture of goat milk cheeses is a growing industry in the US and producing high quality cheeses are a key to its continued growth. Because many goat herds are managed to begin milking at the same time and only for approximately 24 weeks out of the year, the effect of stage of lactation on the quality of the cheesemilk and the resulting cheeses must be established. Multiple batches of Colby and Cheddar cheeses were made using whole milk from Alpine goats at the beginning, peak, or end of their lactation cycles. Rheological properties were measured for all cheeses within one week of being manufactured using a universal testing machine, a torsion gelometer, and a dynamic analyzer. Cheeses made during the peak of lactation had the highest values for hardness, chewiness, shear rigidity at point of fracture, elastic and viscous moduli, and complex viscosity. Cheddar had higher values than Colby cheeses. Shear strain at the point of fracture was the only property measured in this study that decreased at the peak of lactation for both cheeses. Cohesiveness values remained stable over the length of lactation and were similar for Colby and Cheddar cheeses. Changes in the compositional and physicochemical properties of milk at the onset and near the termination of lactation altered the cheesemaking properties of the milk and affected the textural properties of semi-hard and hard cheeses. Stage of lactation should be considered when selecting suitable cheesemilk for the production of high quality and uniform cheeses.

Session 14A, Dairy Foods: General developments in dairy technology I
8:30 AM - 12:00 PM, Sunday AM

2003 IFT Annual Meeting - Chicago,