Whey protein off-flavors affect product applications.

Whey proteins are popular value-added ingredients. But they bring with them the problem of flavor variability. Off-flavors in whey proteins that form during their processing or storage may carry into ingredient applications and negatively impact acceptance of the end product.

Most research has not addressed this issue. So, scientists at North Carolina State University wanted to determine if off-flavors documented in whey proteins negatively impacted consumer acceptance of protein shakes and acid beverages made with these ingredients. They found that off-flavors in whey proteins, documented by trained panelists, can carry into ingredient applications and negatively affect consumer acceptability. The upshot of their research: different flavor specifications should be developed for different ingredient applications.

In tests, a trained panel screened 10 rehydrated whey proteins--five whey protein isolate (WPI) samples and five whey protein concentrate (WPC 80%) samples--using an established lexicon. Investigators selected five whey proteins (three WPC 80% samples and two WPI samples) for further testing. Two samples of WPC 80% and a WPI sample displayed distinct off-flavors. The other WPC 80% and WPI samples were used as controls and were free of off-flavors.

Difference tests using rehydrated proteins were conducted to determine if 50 consumers could detect differences between off-flavored and control products. Researchers incorporated WPC 80% into protein shakes. WPI samples were incorporated into clear acidic protein beverages. Descriptive sensory analysis was undertaken to determine the potential for consumer acceptance. Descriptive panelists documented sweet aromatic and cardboard flavors in the control whey proteins. Free fatty acid and cabbage flavors, and a bitter taste were documented in the off-flavored whey proteins.

Consumers could detect differences between the control and off-flavored whey proteins when evaluated alone, with no ingredient application. Descriptive panelists documented off-flavors in ingredient applications made with the off-flavored WPI samples. Consumer acceptance scores were lower for ingredient applications made with two off-flavored whey proteins, but were not different from the control for one of the off-flavored whey proteins.

Further information. MaryAnne Drake, Department of Food Science, North Carolina State University, 236-E Schaub Hall, Campus Box 7624, Raleigh, NC 27695; phone: 919-513-4598; fax: 919-515-4694; email: mdrake@unity.ncsu.edu.