Controlled Environment Agriculture

Spinach Nutritional Value Improvement

Improvement of Crop Nutritional Value for Humans

Corey Johnson-Rutzke

Much of agricultural science has been focused on the increased production of biomass. Agriculture has the tremendous potential to be driven toward the improvement of the nutritional value of the food crops produced for human consumption (Combs et al., 1997, Eur. J. Clin. Nutr. 51:s32-33). The cost of exploration and development of new methods is prohibitive to farmers. The exploratory work must be continued through universities and government organizations interested in optimization of food value, such as USDA and NASA.

Cornell CEA has developed a method (Pat. Pend. #60/244,050) of increasing the nutritional value of spinach for human consumption. Spinach contains significant amounts of an anti-nutritive calcium-binding component, oxalic acid. Over 30 years ago, an enzyme that breaks down oxalic acid into CO2 and H2O2 was discovered and determined to be present in spinach leaves. However, this naturally occurring enzyme is inactive in spinach leaves because of the presence of nitrate, a common form of nitrogen-fertilizer. The CEA technique invented to improve the nutritional quality of spinach provides the precise environment allowing the oxidase enzyme to naturally break down oxalate. The technique reduces oxalate by 2/3rd in one week, by cutting off the nitrate supply prior to harvest.

In another study, it was determined that pre-harvest light quality (color or wavelength) influenced the nitrate content of spinach. Spinach grown in the presence of supplemental far-red light had 10 times more nitrate than spinach grown in the presence of supplemental red light. Light-emitting diodes (LEDs) were used in the study. (Johnson et al., 1999, SAE 1999-01-2107).

This research project was funded by NASA GSRP (NGT10-52607).

Array of LEDs

Light-emitting diodes (LEDs) are used to determine the influence of light-wavelength (color) on foods grown in controlled environments.

Spinach plants Spinach plants

Research at Cornell University CEA showed that anti-nutritive oxalate levels in spinach can be reduced by two-thirds through control of the environment prior to harvest.