Equivalent System Mass of Producing Yeast and Flat Breads from Wheat Berries, A Comparison of Mill Type

Wheat is a candidate crop for the Advanced Life Support (ALS) system, and cereal grains and their products will be included on long-term space missions beyond low earth orbit. While the exact supply scenario has yet to be determined, some type of post-processing of these grains must occur if they are shipped as bulk ingredients or grown on site for use in foods. Understanding the requirements for processing grains in space is essential for incorporating the process into the ALS food system. The ESM metric developed by NASA describes and compares individual system impact on a closed system in terms of a single parameter, mass. The objective of this study was to compare the impact of grain mill type on the ESM of producing yeast and flat breads. Hard red spring wheat berries were ground using a Brabender Quadrumat Jr. or the Kitchen-Aid grain mill attachment (both are proposed post-harvest technologies for the ALS system) to produce white and whole wheat flour, respectively. Yeast bread was made using three methods (hand+oven, bread machine, mixer with dough hook attachment + oven). Flat bread was made using four methods (hand+oven, hand+griddle, mixer+oven, mixer+griddle). Data on all inputs (active time, passive time, mass and volume of ingredients and equipment, power) were measured and used to calculate ESM. Assumptions were based on data in NASA documents. Data were analyzed using PC-SAS with significance at P < 0.05. Grain mill type significantly (P < 0.05) influenced the ESM of making both bread types; and the Brabender Quadrumat Jr. contributed significantly (P < 0.05) more mass than the Kitchen-Aid grain mill to the ESM for producing both types of bread. Results can be used by systems analysts to define energy and volume requirements for the food system and by researchers to select and modify food production scenarios.