02290nas a2200229   4500008004100000245013700041210006900178300001400247490000700261520154500268653002201813653001501835653001101850653002001861653002001881653003501901100001801936700002101954700002001975700001701995856004802012       2011                        eng d00aHardwood Ash Nixtamalization May Lead to False Negatives for the Presence of Maize by Depleting Bulk delta13C in Carbonized Residues0 aHardwood Ash Nixtamalization May Lead to False Negatives for the  a2726-27300 v383 a<p>Among the multiple proxies for detecting maize in precontact economies is the use of δ<sup>13</sup>C analysis of carbonized residues from ceramic cooking vessels. Although maize horticulture was widely established in Eastern North America (ENA) by A.D. 1000, there are carbonized residues from ceramic assemblages after this date that lack the elevated δ<sup>13</sup>C values indicative of the presence of maize. This may be due to the true absence of maize, or other factors including the masking of maize. Prior experimental research by Hart et&nbsp;al. demonstrated that the addition of C<sub>3</sub> plants or consumers to two part mixes with maize can mask maize presence even when maize is the dominant ingredient. Here we investigate the effect of alkali processing of maize (nixtamalization) on δ<sup>13</sup>C using the widespread ENA process of boiling maize kernels with wood ash, a C<sub>3</sub> product, to create hominy. Our experiments test whether or not the process of hardwood ash nixtamalization can mask the presence of maize in adhering carbonized residues by depleting δ<sup>13</sup>C values, and whether there is a reciprocal δ<sup>13</sup>C enrichment effect on the hardwood ash employed in nixtamalization. Overall, there is substantial δ<sup>13</sup>C depletion of residues when maize is cooked with hardwood ash, and hardwood ash cooked with maize shows the reciprocal enrichment. Therefore, the depleted values after the adoption of maize may be false negatives due to the nixtamalization process.</p>
10aAlkali processing10aBulk δ13C10aHominy10aMaize histories10aPottery residue10aPrehistoric cooking techniques1 aLovis, W., A.1 aUrquhart, G., R.1 aRaviele, M., E.1 aHart, J., P.  uhttp://dx.doi.org/10.1016/j.jas.2011.06.01001557nas a2200205   4500008004100000245015100041210006900192300001400261490000700275520085700282653001501139653001801154653002001172653003501192100001701227700002101244700002001265700001801285856004801303       2009                        eng d00aNon-linear Relationship Between Bulk d13C and Percent Maize in Carbonized Cooking Residues and the Potential of False-negatives in Detecting Maize0 aNonlinear Relationship Between Bulk d13C and Percent Maize in Ca  a2206-22120 v363 a<p>Bulk δ<sup>13</sup>C values on charred cooking residues adhering to pottery sherd interior surfaces have been used as a source of information on the histories of maize in various locations in the western hemisphere. This approach is based on an assumption of a linear relationship between the percent maize in the resource mix cooked in a pot and δ<sup>13</sup>C. Previous experiments suggest that this relationship is non-linear, and maize may not be identified from bulk δ<sup>13</sup>C values even when it contributed substantially to the resource mix. A second round of experiments, presented here, indicates that the mobilization of carbon from maize and C<sub>3</sub> resources over time is the critical variable in residue formation and the resulting bulk δ<sup>13</sup>C value. This is influenced by the form of maize being cooked.</p>
10aBulk δ13C10aMaize history10aPottery residue10aPrehistoric cooking techniques1 aHart, J., P.1 aUrquhart, G., R.1 aFeranec, R., S.1 aLovis, W., A.  uhttp://dx.doi.org/10.1016/j.jas.2009.06.005