Controlled Heat Processing of Jewel Sweet Potatoes for Puree Production1

ABSTRACT ‘Jewel’ sweet‐potato slices 0.5 cm thick were precooked at 100, 125 and 150C for varying periods of time, finish‐cooked for 15 min at 150C, and pureed. Selected chemical and physical properties of the purees were compared to a puree prepared from conventionally baked sweet potatoes (1.25 h at 195C). Purees from the controlled heat process were also compared to the baked puree by a sensory panel. Of all the treatments, puree from the 100C, 6‐min precook treatment was the most silimar to puree from baked sweet potatoes with respect to chemical and physical characteristics. The sensory panel found the two purees to be different, but were equally divided when asked to express a preference. Subsequent analysis showed that the starch of the baked control had been more completely hydrolyzed than the starch of the other treatments. This was reflected by higher maltose, lower starch content and by decreased starch molecular size and viscosity of the control compared with the other treatments.