Stone-boiling maize with limestone: experimental results and implications for nutrition among SE Utah preceramic groups

Abstract

a b s t r a c tGroups living on Cedar Mesa, SE Utah in the late Basketmaker II period (Grand Gulch phase, AD 200e400) were heavily maize-dependent, but lacked beans as a supplemental plant protein, and pottery vessels for cooking. Common occurrence of limestone fragments in their household middens suggests 1) limestone may have been used as the heating element for stone-boiling maize and 2) this practice might have made some maize proteins more available for human nutrition. Experiments examined these possibilities; results indicate that stone-boiling with Cedar Mesa limestone creates an alkaline cooking environment suitable for nixtamalization of maize kernels, and that maize cooked in this fashion shows significant increases in availability of lysine, tryptophan, and methionine. Archaeological limestone fragments from a Grand Gulch phase site show amounts of fragmentation and changes in density consistent with repeated heating. While not conclusive, these data indicate that further research (e.g., examination of archaeological limestone fragments for maize starch grains or phytoliths) is warranted. It is suggested that greater attention be paid to archaeological indications of stone-boiling with limestone among maize-dependent but pre-pottery societies.

Contribution of strontium to the human diet from querns and millstones: an experiment in digestive strontium isotope uptake

“…For example, it was not uncommon for 19th‐century bakers to add chalk (CaCO 3 ) or other substances to their bread flour (Accum ) and the nutritionally beneficial Mesoamerican practice of nixtamalization involved cooking with lime or limestone (also CaCO 3 ) before grinding (Coe , 14; Ellwood et al . ). Pica and geophagy, the practice of consuming non‐food substances, is remarkably prevalent across human cultures and time particularly, and crucially given when deciduous and permanent tooth enamel is mineralizing, in pregnant women and children (Young ; Henry and Cring , 189–191).…”

The nutritional context of the Pueblo III depopulation of the northern San Juan: Too much maize?

“…Most New World use of maize begins by boiling whole kernels in an alkaline solution, usually produced by lime, rendering "hominy," the so called nixtamalization process. The hominy is either used directly or ground while moist into "masa" and made into things like tortillas (Katz et al, 1974(Katz et al, , 1975Ellwood et al, 2012). This boiling in lime water makes more lysine and tryptophan biologically available.…”

“…Lysine and tryptophan are two essential amino acids which cannot be synthesized in the human body and are thus necessary components of the diet (Geissler and Powers, 2009:60-68). Lysine and tryptophan occur only in low amounts in maize (Katz et al, 1974;Ellwood et al, 2012). Maize is actually a pretty good source of protein averaging about 8% protein, so it is the low amounts of these two amino acids that limit the amount of reliance on maize for a healthy diet (Fig.…”

“…7). Interestingly, in earlier Basketmaker II times nixtamalization using limestone stone boiling appears to have been common in at least some areas (Ellwood et al, 2012;Matson, 1991:6).…”

An empirical test of shell tempering as an alkaline agent in the nixtamalization process

“…Then, at 600e900 C and depending on the atmosphere, time, and duration of firing, calcite undergoes calcination or the decomposition into calcium oxide (CaO) and carbon dioxide (CO 2 ) (Ellwood et al, 2013;Feathers, 2006;Herbert, 2008). The recombination of lime with other materials in the matrix into high temperature calcium aluminosilicates increases the strength of the matrix and of the resulting vessel (Feathers, 2006: 92).…”