1. Department of Human Nutrition, Foods and Exercise, College of Agriculture and Life Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061.
2. Corresponding author. Phone: 540-231-6785. E-mail: barbeau@vt.edu
3. Department of Crop and Soil Environmental Sciences, College of Agriculture and Life Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061.