UBC Theses and Dissertations
Stable carbon isotope analysis and maize-stalk beer diet in rats : implications for the origins of maize Canal, Maria Cecilia
Maize is one of the world’s most important staple crops but theories explaining the ancestry of maize are focused mostly on domestication as it relates to food for human consumption. Much research was conducted on the wild ancestor of maize; current trends support teosinte as the ancestor of maize; but the question that remains unexplained is why people initially cultivated teosinte considering the plant has so little yield? Smalley and Blake (2003), elaborating on a concept proposed by Iltis (2000)’ explored this question. Iltis argued that the ancestor of maize was first domesticated for its sugar content. Building on this idea, Smalley and Blake suggested also the possibility of making alcoholic beverages. This suggestion that the ancestor of maize was selected for its sugar content changes the focus of early maize research. Maize is found in the archaeological record at 5400 B.P. but was not yet a staple food crop. Researchers must consider alternate uses early Mesoamerican people had for this plant. The production of alcohol from the sugary maize stalk is an example of an alternate use for maize. In an attempt to understand what occurred between the initial appearance of maize as a crop and its use as a staple food source, researchers have been studying the plant’s C₄, photosynthetic pathway and its impact on bone chemistry. The carbon isotope signature in human bone resulting from the consumption of maize is quite different depending on whether the maize is eaten directly as food or first converted to alcohol before being consumed. This study tests the hypothesis that C₄, carbon from maize-stalk beer leaves a signature in bone collagen. Rats were used in a feeding experiment to determine if a diet with a significant component of maize-stalk beer would elevate the stable carbon isotope ratios in the consumers. Results of this experiment showed that maize-stalk sugar converted to alcohol and not raise the stable carbon isotope ratio measured in the rats. This suggests that archaeologists must look for raised stable carbon isotope values in apatite, rather that collagen, if they are to detect maize alcohol use in ancient populations.
Item Citations and Data