The Quality and Nutrition Laboratory supports research-for-development projects that aim to reduce malnutrition or promote health by improving the nutritional quality of potato and sweetpotato.
The Quality and Nutrition Laboratory evaluates the micronutrient content of potato and sweetpotato cultivars. Iron, zinc, and provitamin A carotenoids are evaluated for projects that aim to reduce malnutrition by improving the nutritional quality of potato and sweetpotato. Antioxidant concentrations are evaluated projects that seek to promote health through the improvement of the antioxidant concentration of these crops.
Fresh or dried samples of unpeeled raw potato tubers and sweetpotato roots are evaluated for carotenoid, polyphenol, ascorbic acid, and mineral content. A selected group of varieties or clones is also analyzed in cooked form.
Chemical analyses are carried out using spectrophotometry, high-performance liquid chromatography (HPLC), and inductively coupled plasma optical emission spectroscopy (ICP-OES) mass spectrometry. Since 2005, more than 500 potato varieties and more than 1,000 sweetpotato genotypes have been analyzed.
Near-infrared reflectance spectroscopy (NIRS) analysis
Although chemical methods are very accurate, the high costs of these methods and the time required for analysis limits their use to small numbers of samples relative to those required in extensive screening and breeding programs.
NIRS is a rapid and relatively inexpensive technique that facilitates analysis of several traits simultaneously. It does not need chemical reagents and avoids contamination with chemical waste.
NIRS calibrations have been developed to estimate the carotenoid and phenolic content of freeze-dried and milled potato and sweetpotato samples. These calibrations are precise and useful for selecting varieties with high, medium, or low concentrations of micronutrients and selecting varieties for starch, protein, and individual sugars.
To date more than 100,000 sweetpotato samples and more than 10,000 potato samples from different breeding programs have been analyzed by NIRS, facilitating the breeding progress for nutritional improvement of potato and sweetpotato.