MICROSTRUCTURES OF OIL ROASTED PEANUTS (ARACHIS HYPOGAEA L. CV. VA 98R) AS AFFECTED BY RAW MOISTURE CONTENT

Raw runner type peanuts were dried to moisture levels of 4.24 and 6.62 g/100g. Each batch was oil roasted at 160°C in pure peanut oil for the amount of time determined to produce a surface color of 48 on the Hunter L scale. The surfaces of the cotyledons were examined by scanning electron microscopy. Escaping steam caused ruptures in the surfaces during the roasting process. The principal differences found were that the higher moisture samples had more complex tears to the outer surface as a result of higher amounts of steam escaping from the interior. The interior cell components were found to be more distorted and compacted at the lower moisture. Although it was found that in peanuts, shorter heating times were required to reach the desired color at the higher moisture, the large amount of escaping steam resulted in more surface cell destruction than at the lower moisture, where as the lower moisture samples appeared to have more interior cell damage. This may have an effect on the retention of oil by the peanuts during storage.