(318c) The Effect of Microwaving and Ultrasonication on the Yield and Product Profile of Jerusalem Artichoke Extracts

Production of fructo-oligosaccharide syrups from jerusalem artichoke tubers was studied at 20 ? 60ºC by determining the yield, degree of polymerization (DP), product profile (DP of up to 6) and prebiotic effect. Citric acid, added in order to minimize browning, and temperature were found to improve functionality. Ultrasonication (US), included for probable improving effect on mass transfer and hydrolysis, decreased the amounts of glucose, fructose and sucrose (DP 1-2), increased the amounts of oligosaccharides with DP 3-6, with some decrease in the yield. The better functionality of US syrups were also indicated by the prebiotic property measurement with Lactobacillus Plantarum 1193. The application of US at 60°C as compared to 20°C almost tripled the amounts of functional sugars. Syrups containing 17% functional sugars were obtained at 60°C. In order to obtain the largest proportion of monosaccharide units as functional sugars, 10 day storage at 4°C after harvest was indicated. It was also seen that ultrasonication did not affect the physical properties, except that the darkness was doubled. Short time (1 min) microwaving and microwaving cooking (20 min) decreased the amount of waste sugars and increased the amount of functional sugars. The color and the darkness of the syrup was tripled via microwaving, but no change in density and viscosity of the syrups were observed.