Standard Reference Material (SRM) 2385 consists of small jars of slurried spinach--pure spinach that's been blanched, pureed and passed through filter screens. The concentrations of vitamins and other constituents have been measured and certified, so that the food industry can use the SRM to validate analytical methods and provide accurate nutritional information for its products. An analytical method is evaluated by using it to measure constituents in the SRM and then comparing the results to the NIST-certified values.
The NIST values confirm that spinach is rich in antioxidants--both beta-carotene and lutein. Although the actual amounts look small (the antioxidants constitute 0.0019 percent and 0.0033 percent of the spinach by mass, respectively), spinach contains far more of the two combined than most other fruits or vegetables. Antioxidants help fight formation of free radicals, highly reactive molecules that can damage DNA and are implicated in the development of certain diseases. Beta-carotene converts to vitamin A in the body and is needed for healthy vision, skin and hair. Lutein is a pigment found in the retina and may help guard against eye diseases such as age-related macular degeneration. Among its other attributes, spinach also contains 1.55 percent dietary fiber by weight.
The new SRM was developed at the request of the food industry and with the help of more than 10 food manufacturers. NIST now supplies 37 different food SRMs to the industry, one or more for each of the nine sectors of the Association of Analytical Communities' food triangle, which categorizes food based on its fat, carbohydrate or protein content. The food triangle helps to assure the availability of validated analytical methods for all types of foods.