The study hypothesis is that foods will sustain functional ingredients for an extended shelf life if compatible formulation, processing, and storage conditions are achieved. Current spaceflight foods are being evaluated to determine if their nutrient profile supports positioning as a functional food and if the stability of the bioactive compound within the food matrix over an extended shelf life correlates with the expected storage duration during the mission.
Twelve foods that were thought to have a significant concentration, or a concentration significantly greater than most spaceflight foods, of bioactive compounds (lycopene, lutein, omega-3 fatty acids, phenolics, sterols, and flavonoids) were selected for the study from the International Space Station food provisions. Recently produced food samples were sent by overnight shipment to the Food Composition Laboratory of the Linus Pauling Institute at Oregon State University (Corvallis, OR) for bioactive compound analysis. Three packages of each product were blended together for the analysis to reduce package-to-package variability. Samples were analyzed initially and after 3, 6, and 12 months of storage, dependent upon storage temperature (4°C, 21°C, or 35°C) within the Space Food Systems Laboratory environmental chambers. Final storage analysis will occur at 2 years.
The ability to provision high-lycopene, high-lutein, or high-omega-3 fatty acid foods within the spaceflight food system has been demonstrated by the identification of the foods of this study and their initial chemical analysis. Sterols can be supplied through cumulative diet; however, a single food with adequate sterol content for functionality is unlikely. Total polyphenol delivery appears stable and adequate, however the physiological relevance of the overall stability is currently unknown in relation to the importance and stability of individual phenolic compounds that were not specifically evaluated in this study. The stability of bioactive compounds within the identified foods varies with the bioactive compound and the storage temperature. The data would seem to suggest that some bioactive compounds, like lycopene, lutein, marine omega-3 fatty acids, and rice sterols, plateau at some equilibrium concentration. The anthocyanin stability is greatly related to storage conditions as is lutein stability in leafy vegetables. The sterol stability in nuts would seem to relate to storage duration but not temperature. More data is needed to confirm these observations.
Some bioactive compounds can be supplied across the space food system through a variety of foods. However, omega-3 fatty acids, particularly EPA and DHA, and lutein are found in very specific food items. The ISS provisioning menu likely does not have a variety of foods with these specific bioactive compounds to fully institute a meal plan to address those health issues requiring compound-specific mitigation without creating a secondary issue of menu fatigue. It is yet unknown whether the bioactive compounds will remain stable over the extended shelf life of five years required for a Mars mission. The functionality only exists if the chemical stability of the compounds maintains the efficacious structure for a long shelf life. Hence, the viability of functional foods for spaceflight, or stabilization countermeasures if necessary, has yet to be established.
Abstracts for Journals and Proceedings
Bermudez-Aguirre L, Cooper M. "Functional Foods Baseline and Requirements Analysis." Presented at the 2015 NASA Human Research Program Investigators' Workshop, Galveston, Texas, January 13-15, 2015.
Abstract Book, 2015 NASA Human Research Program Investigators' Workshop, Galveston, Texas, January 13-15, 2015. , Jan-2015