[123]

FORMULATION OF ALS CROP-LIST DIETS USING SIMPLEX OPTIMIZATION.  C.M. Gregson¹, L. Rodriguez² and T-C. Lee¹. ¹Department of Food Science, ¹CAFT, ²Department of Bioresource Engineering and ^1,2NJ-NSCORT, Rutgers, the State University of New Jersey, New Brunswick, N.J. 

     Food within an Advanced Life Support (ALS) System will be obtained primarily from a small number of crops. However, nutritional requirements for ALS and long-term missions have not yet been clearly established. Due to these limitations, optimization of crew diets is difficult. The objective of this work is to provide a methodology to formulate diets that meet requirements for nutritional content, system cost and variety, and to show how the resulting diet is influenced by the objective function.

     Previous diets were evaluated using published data based on Earth-grown crops as input information. Optimization of diets based on the BVAD crop-list was performed using the Simplex algorithm. Results show that diets can be readily optimized for macronutrients through the use of the sum of squared differences approach. Optimization for all nutrients (macro and micro) proved more challenging and showed that at least a small number of micronutrients must be provided through alternative sources. Optimization for growth efficiency of crops alone resulted in a diet based on a single crop unless stringent constraints were included. Optimization for multiple objectives, using novel objective functions such as combinations of growth efficiency and macronutrients, provided interesting information. 

     The work shows a powerful methodology, using linear programming, for optimizing crew diets.  Results can be utilized for reconsideration of crop selection lists and biomass production schemes.  Once more information is available regarding crew nutritional requirements, crop nutritional value and plant growth performance, more accurate optimizations can be performed.

     (Supported by NJ-NSCORT)