Basketmaker II Stone-Boiling Technology at Cedar Mesa, Utah:

Transcription

1 Basketmaker II Stone-Boiling Technology at Cedar Mesa, Utah: An Experimental Study by Emily Holstad, Paul Scott, William D. Lipe, and John G. Jones

2 The Hypothesis R.G. Matson (1991) noted that Basketmaker II limestone fragments present on Cedar Mesa habitation sites may have been exhausted boiling stone detritus from an early form of alkaline maize processing, known also by its Aztecan term as nixtamalization. Limestone Scatters (NR15) from a Cedar Mesa Basketmaker II habitation site. (Photo by E. Holstad, August 2009)

3 Phase I: The Three Phases Could natural Cedar Mesa Limestone be heated high enough to create chemical lime? Phase II: What, if any, nutritional shifts result from using the same natural heated limestone to boil maize? Phase III: Are there specific physical signatures in archaeological limestone that indicate heat treatment?

4 Phase I: Can Cedar Mesa Limestone Be Heated High Enough To Create Chemical Lime? Studies show that the pre-treatment of modern corn through soaking it in water with slaked lime, or calcium hydroxide, produces nutritionally beneficial results (Gutierrez-Dorado et al. 2008). Thus, if heated limestone was an effective nixtamalization treatment for Basketmaker II groups, stone-boiling ph levels were expected to be similar to those seen in the commercial slaked lime mixtures used today (or around 11.4 to 11.6).

5 Phase I: Methods Natural limestone was collected near Snow Flat Road on Cedar Mesa Stone Sets Were Heated for 3 hours (Interval Scale): 300 C to 900 C range Samples were then immediately placed in room-temperature distilled water: 1:2 limestone to distilled water ratio Natural Limestone Collection Area Limestone was steeped and water temperature monitored over 24 hours Water samples were collected for ph testing throughout steeping (adapted from Matson, Lipe, Haase 1990)

6 Phase I: Results As low as 600 C to 700 C, calcination begins Very high ph values at 800 C and 900 C Effective temperature maintenance at 800 C Temperature: Control (Dist. H2O) 30 Minutes 1 Hour 2 Hours 5 Hours 10 Hours 24 Hours 300 C C C C C C C C

7 Phase II: Nutritional Assessments of Maize Boiled with Limestone Three selected varieties of maize (analogs for early Zea) cooked with heated limestone were assessed to note shifts in essential amino acids: Lysine Tryptophan Methionine

8 Phase II: Methods Natural Cedar Mesa limestone was dried for 24 hours and then heated for 3 hours at 800 C Limestone was removed from the oven and placed directly into a maize and water mixture: 1:2 water to limestone and 1:3 parts maize to water Maize was heated to between 75 C to 90 C for approximately 20 minutes, after which the mixture was allowed to cool Ten grams of soaked maize were periodically removed, rinsed, ground and dried: These samples were taken each hour for 10 hours

9 Methods Cont. Control samples were cooked in water on a hot plate without limestone and then rinsed, ground, and dried in a similar manner to the limestone-treated set Raw, uncooked controls were also provided

10 Phase II: Results 1) Differential amino acid content among the three maize varieties ( Corn type effect) 2) Comparative increase in limestoneboiled maize against controls: a) 1.9% more methionine b) 4.3% more tryptophan c) 6.1% more lysine 3) A significant difference existed among the limestone-boiled corn types only for the level of methionine 4) Steep time proved irrelevant Tarahumara Chomo Limestone Boiling

11 Phase III: Archaeological Assessments +1.0 Veres Site (42SA7406) +1.0 Plan Map Area A True North Magnetic North Firepits #1 (below) and #2 (above) 3M Pithouse Structure +1.0 Datum Slab-Lined Entryway Dogleash Unit #2 0.0 Dogleash Unit #1-1.0 Area B -2.0 *Dogleash Unit #3 Area C 32 M South of the NW Corner of the Slab-Lined Entryway View to the SE of Dogleash Collection Unit 1: sandstone pithouse entryway in foreground (photo by William D. Lipe, April 27th, 2010) (adapted from Pollock 2001) Veres Site, a Basketmaker II Habitation Site in SE Utah

12 Phase III: Methods Experimental analyses were designed to map specific heat markers by subjecting natural Cedar Mesa limestone to a series of three controlled heating and steeping sessions that attempted to map shifts in: Density (stone weight/water displaced) Color change Heat damage, such as cracking or spalling

13 Phase III Results: Physical Markers 1) Color Shifts (reddening) Unheated Half Heated to 600 C 2) Cracking Both Heated to 700 C and Steeped 3) Fragmenting Heated to 800 C and Steeped

14 Phase III Results: Density 5.00 Density Shifts Through Heating and Steeping density (grams/cc) No Heat/Steep First Heat/Steep Second Heat/Steep Third Heat/Steep Unheated Stone 600 C 700 C 800 C

15 Phase III: The Veres Comparisons Limestone Fragments: Highest Density Recorded From Heat-Treatment (3.0) Raw Limestone Density (2.37) Density

16 Conclusions All three methods of experimentation outlined in Phases I through III produced data suggesting that Cedar Mesa Basketmaker II (BM II) groups utilized local limestone resources to stone boil maize: Limestone, when heated, creates a natural form of calcium oxide, or quicklime Nixtamalization treatments of maize with limestone improve overall protein content Veres Site data indicate that Basketmaker II archaeological limestone fragments had been exposed to high levels of heat

17 Acknowledgments R.G. Matson Adrienne Moran Lauter Karen Adams Franklin F. Foit Melissa Goodman-Elgar Timothy Kohler Colin Grier Robert Quinlan Native Seeds Search

18 References Boynton, Robert S [1966] Chemistry and Technology of Lime and Limestone. 2nd ed. Wiley-Interscience Publication, John Wiley & Sons, New York. Gutierrez-Dorado, R., A.E. Ayala-Rodriguez, J. Milan-Carrillo, J. Lopez-Cervantes, J.A. Garzon- Tiznado, J.A. Lopez-Valenzuela, O. Paredes-Lopez, and C. Reyes-Moreno 2008 Technological and Nutritional Properties of Flours and Tortillas from Nixtamalized and Extruded Protein Maize. Cereal Chemistry 85(6): Katz, S.H., M.L. Hediger, and L.A. Valleroy 1974 Traditional Maize Processing Techniques in the New World. Science 184: Matson, R.G Origins of Southwest Agriculture. University of Arizona Press, Tucson. Pollock, Katherine H Pits Without Pots: Basketmaker II Houses and Lithics of Southeastern Utah. Unpublished Master s thesis, Department of Anthropology, Washington State University, Pullman. Wacher, Carmen 2003 Nixtamalization, a Mesoamerican Technology to Process Maize at Small-Scale with Great Potential for Improving the Nutritional Quality of Maize Based Foods. Food-based Approaches for a Healthy Nutrition. Departamento de Alimentos y Biotecnologia, Mexico.