CHARACTERISTICS OF PEANUT KERNELS ROASTED UNDER VARIOUS ATMOSPHERIC ENVIRONMENTS

Peanut kernels (Tainan 9, a Spanish cultivar) were roasted in a stainless steel vessel (600 mL) at 210-degrees-C under a continuous flow of air, N2, CO2, and O2 at 1.3 L/min (LPM) and without aeration as a control, for 0, 10, 18, and 25 min. Hunter L values of the deskinned kernels decreased while a and b values increased with roasting time. The most and the least significant changes in color of peanuts occurred under O2 and CO2 atmospheres, respectively. The best flavor was obtained by roasting peanuts under N2 or CO2 for 18 min. Decreases of total alpha-amino nitrogen, glucose, sucrose, and conarachin contents and specific lipoxygenase activity were dependent on the extent of heat treatment (roasting time) rather than on atmospheric gas composition. Peanuts roasted under O2 for 25 min were more stable during initial stages of an oven test at 62-degrees-C compared to peanuts roasted under other types of atmospheric gas.