Date of Award:

1960

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Nutrition, Dietetics, and Food Sciences

Department name when degree awarded

Nutrition and Biochemistry

Abstract

Levulose (D-fructose, fruit sugar), C6H12O6 is a white crystalline ketohexose. This sugar has distinctive properties which make it of commercial interest. It is more costly than ordinary table sugar (sucrose). Levulose is characterized by a high degree of sweetness (6), great solubility (20), and medical usefulness when administered intravenously. Joslin (21) and Root and Baker (32) found levulose to be of great value in the treatment of diabetes. According to Daniel (8), it is assimilated and oxidized more quickly than sucrose, supplying the necessary energy requirements for the human system. Additional uses of levulose have been reported by McGlumphy and Eichinger (27), which include its application to improve the quality and the flavor of jams, jellies, marmalades, canned fruits, carbonated beverages, and corn sugar.

Plants of the family compositae contain large amounts of levulose polymers, but the dahlia, chicory, and Jerusalem artichoke are the most promising sources because of the high levulose content and the ease of production (13). The tubers of Jerusalem artichoke were used in this study because they offer an inexpensive and prolific source from which levulose can be extracted.

Since most of the levulose units in the artichoke tubers are linked together to form inulin or carbohydrate intermediate compounds between inulin and levulose, it is necessary to hydrolyze the material in order to free the levulose. Several investigators have reported the use of acid compounds. Anderson and Greaves (1) used H2SO4 for hydrolysis, while Yamasaki (41) used HC1 for the same purpose. Kleiderer and Englis (23) obtained complete hydrolysis of inulin by use of CO2 and SO2 at a pressure of 1000 pounds per square inch at 150o C. for 60 minutes.

As fare as can be determined from the literature, little work was done prior to 1953 using radioactive material to study peaceful uses of atomic energy. Since that time, a law was passed by the United States Congress authorizing the use of radioactive material for peaceful purposes, thereby making it possible to use atomic energy for this study. Since previous work has shown that gamma rays can convert starch to simple sugar (33), it was therefore, assumed that the inulin and other carbohydrate intermediates of Jerusalem artichoke upon hydrolysis by beta or gamma rays might yield fructose (35).

The primary purpose of this study was to determine the effects of beta and gamma rays on inulin and other carbohydrate intermediate compounds present in the Jerusalem artichoke tubers and to compare the results with those obtained by hydrolysis with radiation plus hydrochloric acid.

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