Protein Digestibility in Older and Younger Adults

Inclusion Criteria: * Age: 20-35 years or 65-80 years * Body Mass Index (BMI): 20.0 - 30.0 kg/m2 * Veins suitable for blood sampling * Healthy as assessed with a questionnaire * Regular and normal Dutch eating habits as assessed with a questionnaire * Having given written informed consent * Willing to comply with study procedures * Accept use of all encoded data, including publication, and the confidential use and storage of all data for 15 years. Exclusion Criteria: * Chronic disease, for example: * Diabetes mellitus, being treated for high blood glucose or increased fasting blood glucose (\> 6.7 mmol/l in finger prick blood) * Active cardiovascular disease * Hepatic disease (e.g. hepatitis) * Renal disease * Cancer * Bowel disease (e.g. inflammatory bowel disease, ulcers, bleeding) * Pancreatitis * History of medical or surgical events that may affect GI function and the study outcomes, for example: * Bariatric surgery * Gastrointestinal tract surgery * Digestive tract disorder * Chewing problems * Medicine use that interferes with GI function and the study outcomes, for example: * Glucose lowering drugs * Proton pump inhibitors * Laxatives * Habits that interfere with the study outcomes: * Probiotics and/or protein supplement use * Smoking * Drug abuse * Alcohol consumption for men \>21 units/week and \>4/day and for women \>14 units/week and \>3/day * Following a weight-loss diet, medically prescribed diet or other diet with a low calorie intake or an unbalanced nutrient intake like a vegan or very low carbohydrate diet * Moderate to high intense physical activity for more than 5 hours a week * Difficulties with eating breakfast in the morning * Other: * Self-reported allergy or intolerance to the tested products (milk, sorghum, black beans) * Weight loss of more than 3 kg in the month prior to study screening * Being pregnant * For men: Hb \<8,5 mmol/l and for women: Hb \<7,5 mmol/l * Recent blood donation (\<2 months prior to start of the study) * Current participation in other research and \<2 months previous participation in other research * Not having a general practitioner * Not willing to accept information-transfer concerning participation in the study, or information regarding his or her health, like laboratory results and eventual adverse events to and from his general practitioner * Working at the department of Human Nutrition and Health at Wageningen University \& Research