Flour. Technology exists for fortifying cereal flour with vitamin C, but losses during storage, transport and preparation have to be carefully assessed.
Whole grains. Several studies on the fortification of whole grains with vitamin C have been undertaken, e.g. by USAID. The main constraint with this technology-sucrose syrup solutions are sprayed on the surface of the grains-is the product's limited shelf life and the stability of the vitamin after exposure to heat during shipment (heat exposure can be as high as 40-50°C) and during milling and pounding (mechanical heat). Vitamin C losses during exposure to humidity and oxygen, in addition to losses during cooking, could be quite high. An advantage of un-milled cereals is that whole grain can be more easily salvaged when bags break during transportation.
Simulated rice kernels have been developed for rice fortification. Vitamin A and other vitamins can be incorporated into the simulated kernel mix which is added to normal white rice at an appropriate proportion (e.g. 1:200) to provide the proper nutrient level in the fortified rice. During cooking the nutrients are released from the premix kernels and evenly distributed throughout the product. The simulated rice kernels have the same shape and colour as the regular rice and therefore cannot be picked out and discarded as foreign particles before cooking. However, the fortification of rice with vitamin C could be a problem because of the high vitamin losses if the cooking water is discarded.