Vitamin E and oxidative stability during storage of raw and dry roasted peanuts packaged under air and vacuum

The relationship between vitamin E and the oxidative stability of raw and dry roasted peanuts was studied during storage at 21 degrees C under air and vacuum. Lipid oxidation was monitored by peroxide values (PVs) and :37, conjugated diene values (CDVs). In air, PV (meq/kg) for roasted peanuts reached 47 by 12 wk, whereas that for raw peanuts was below 2 after 38 wk. Under vacuum, lipid oxidation was significantly retarded (P < 0.05). Tocopherols of raw and roasted peanuts exponentially decreased with increasing PV. After 12 wk, about 50% of alpha-tocopherol (alpha-T) was lost for roasted peanuts under vacuum compared with about 90% under air. For raw peanuts, more than 70% of each tocopherol remained after 38 wk under air and vacuum. In general, alpha-T showed the least stability in roasted peanuts compared with other tocopherols under the reported storage conditions.