Walter et al. (1982) used the different treatments of peeling sweet potatoes in a boiling, NaOH solution. The different treatments were: 6 minute peel (6p), 20 minute pre-soak in water (55องศา) followed by a 6 minute peel (20S), 30 minute pre-soak in water (80องศา), followed by a 6 minute peel (30S), 15 minute peel (15p). The area of tissue which was affected by heat was excited and analysed for odihydroxyphenols (DP0 and carotene destruction and sugar formation. the data showed that roots peeled by 6P or20S treatments could discolour as a result of the PPO-DP reaction. 15P and 30S did not show discoloration because both treatments are vigorous enough to inactive the PPO system. All treatment except 6P caused the inactivation of amylolytic enzymes. Carotenoid destruction was not detected,