Use of gamma Radiation as a Form of Preservation of Sweet Potatoes: Phase 2: Final Report for Period January 1, 1986-December 31, 1986

摘要

Effects of gamma radiation and storage time on storage roots of 'Georgia Jet' and 'Jewel' sweet potatoes and on the sweetpotato weevil Cylas formicarius elegantulus (Summers) were studied. The storage roots were irradiated: immediately after harvest and before curing immediately after curing, or after curing plus three months of storage. Storage was at 14 to 16 sup 0 C with 85 to 90% relative humidity. Sweet potatoes were examined at different stages of storage over nine months for sprouting, storage rot development, flesh color, texture, moisture, carbohydrates, starch granules - cell ultrastructure, ascorbic acid, enzyme activity, peroxidase and polyphenol oxidase, protein and organoleptic properties. It was found that sweet potatoes should never be irradiated prior to curing since increased rotting results. No significant difference was found in storage rot development between control and irradiated after curing at doses up to 0.20 kGy. Nutritive components were in most cases not significantly affected by radiation at the four doses studies. Nutritive qualities of moisture, texture, starch, ascorbic acid, sugar, color and enzymes all changed to one extent or another with increased storage time. Irradiation speeds up the process of cell wall collapse and accumulation of cytoplasmic debris, but this also occurs later in the control. Isoelectric focusing results demonstrate that radiation effects on proteins are very small up to a dose of 0.20 kGy. HPLC results indicated that irradiation of the roots caused accumulation of new proteins while impairing the formation of others. Fecundity of the sweetpotato weevil was reduced at 15 sup 0 C compared to 28 sup 0 C. (ERA citation 12:035812)