Three significant problems with food supply in bioregenerative lifesupport systems are addressable through use of fermented foods. The quantity of inedible and marginally edible biomass can be reduced; the hedonic quality of the diet can be enhanced; and food storage constraints can be relaxed due to the superior keeping qualities of fermented products. The authors have assessed potentially available materials and fermentation processes used worldwide, to identify promising food fermentations for use in lunar and planetary stations.
Conversion of inedible biomass into acceptable food may include hydrolysis of waste biomass to produce sweeteners and acidulants; fermentation of physically fractionated biomass such as leaf protein isolates into acceptable foods; mushroom cultivation on agricultural residues; and conversion of volatile fatty acids produced during waste treatment into edible microbial biomass.
Fermentation can also be used to upgrade edible biomass into more palatable and nourishing forms, products with greater culinary versatility or products valued chiefly for their flavor This effect will be particularly valuable as the proportion of food produced on-station rises from the expected 75-85% for early missions to near 100% closure in the long term.
Crop scheduling requirements and crop or equipment failures in a bioregenerative system may result in availability of large excesses of perishable foodstuffs. Fermentations such as pickling provide a quick, low-cost means of preserving leafy and succulent crops unsuited to freezing or drying; they can also reduce the demand on cold-storage space for freezable crops.
The authors will present examples of food fermentations in each category and will review the costs and benefits of using food fermentation processes on lunar and planetary stations.