EFFECT OF HEATING TEMPERATURE AND MICROWAVE PRETREATMENT ON THE FORMATION OF SUGARS AND VOLATILES IN JEWEL SWEETPOTATO

Experiments investigating changes in the concentration of individual sugars in sweetpotato storage roots with cooking and their relationship to the formation of volatile compounds were conducted. During heat treatment maltose concentration increased from 0.03% fresh weight at 25C to 4.33% at 80C, at which temperature maximum synthesis occurred. Microwave pretreatment (2 or 4 min) resulted in a significant decrease in amounts of maltose and volatiles formed. At 80C, approximately 80% of maltose synthesis was inhibited when pretreated With microwaves. Adding maltose into microwave pretreated samples and then cooking in a convection oven restored most of the volatile profile with the exception of phenylacetadelhyde. It was concluded that maltose represents a primary precursor for many of the volatile compounds emanating from baked ‘Jewel’ sweetpotatoes and the formation of these volatiles appears to involve both enzymatic and thermal reactions.