Date

2006

Author

Yıldız (Yiğitarslan), Sibel

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Extraction of fructo-oligosaccharide syrups from grated jerusalem artichoke (JA) tubers was studied by water at 20-60°C by determining the yield, degree of polymerization (DP), product profile (DP of up to 6) and prebiotic effect using Lactobacillus plantarum on samples harvested between October and April, stored for 0-20 days. The optimum solvent to solid ratio was 4, the duration of shaking water bath extraction was 40 min and yield based on JA were 12-17%. Temperature was found to improve yield and functionality, and citric acid, at 26 mM, improved the color and darkness by 70 and 80%, respectively. Short-time (1 min) microwaving prior to extraction increased the yield by about 20%, decreased the amount of sugars with DP 1 and 2 and increased the amounts of oligosaccharides (OS) with DP 3-6, although the prebiotic effect increased only slightly; while the color and darkness of the syrup were tripled. Ultrasound-assisted-extraction (USE) gave best performance at 3 min duration;decreased the amounts of sugars with DP 1-2, increased the amounts of OS with DP 3-6, with 18% decrease in the yield. The better functionality of USE syrups were also indicated by 2.5 times higher growth rate of L.plantarum. The application of USE at 60°C compared to 20°C almost tripled the amounts of functional sugars. In order to obtain the largest proportion of monosaccharide units as functional sugars, 10 day storage at 4°C after harvest was indicated. Ultrasonication did not affect the color but the darkness was doubled. The density and viscosity of all the syrups were practically the same.

Subject Keywords

Oligosaccharides., Functional foods., Probiotics., Inulin.

URI

http://etd.lib.metu.edu.tr/upload/12607908/index.pdf
https://hdl.handle.net/11511/16484

Collections

Graduate School of Natural and Applied Sciences, Thesis