1Plant Foods in Hominin Dietary Ecology Research Group, Max Planck Institute for Evolutionary Anthropology, 2Department of Anthropology, University of Nevada, 3Division of Biological Anthropology, University of Cambridge
Friday 11:00-11:15, Ballroom B
Cooking is widely recognized as a highly significant step in human evolution because it possibly facilitates increased availability of nutrition. Cooking mechanically and chemically changes food, which can increase digestibility. This is particularly important for starchy foods because heat causes starch to absorb water and lose its otherwise highly resistant crystalline structure, a process called gelatinization. Gelatinization makes starch more digestible in the small intestine and increases the bioavailability of nutrition. However, some have questioned whether gelatinization of starch is the main goal of cooking. The Hadza hunter-gatherers of Tanzania roast their wild tubers for only a few minutes on an open high-flame fire. The same tubers are also often consumed raw. These observations led us to propose a series of questions regarding the Hadza tubers: What does brief fire roasting do to the starch? Does the starch require cooking for salivary α-amylase activity? Are there differences in nutrient bioavailability between cooked and uncooked tubers in-vitro? Our results show that tuber starch remains mostly unchanged after brief fire roasting and there is subsequently little difference between cooked and uncooked tubers in nutrient bioavailability in-vitro. We make inferences as to why a subsistence-based population such as the Hadza would practice thermal food processing behaviors that do not seem to alter the nutritional elements of the food itself. In particular, we hypothesize that brief roasting enables faster peeling and ease of chewing of Hadza tubers.