Masters Theses

Date of Award

12-1979

Degree Type

Thesis

Degree Name

Master of Science

Major

Food Science and Technology

Major Professor

Sharon L. Melton

Committee Members

H. O. Jaynes, J. L. Collins

Abstract

The triglyceride (TG) structure of naked-seeded pumpkin seed oil (Cucurbita pepo, var. Lady Godiva) was determined. Crude oil of naked-seeded pumpkin seed was extracted from dried, ground whole seeds, alkali refined, bleached and deodorized. The oil was separated into four fractions by low temperature crystallization at 10 degree intervals from -30 to 0°C. The refined oil and oil in each fraction were hydrolyzed by pancreatic lipase, and the 2-monoglyceride was isolated by thin layer chromatography. Fatty acid composition of the refined oil, the oil in each fraction and the respective 2-monoglyceride were determined by gas chromatography. The fatty acid composition in the refined oil was 14.96% palmitic, 4.78% stearic, 49.11% oleic, 30.87% linoleic and 0.28% linolenic. Percentages of alignment structure of the triglycerides molecules (ASTM) of the oil from the naked-seeded pumpkin seed were calculated to be; SSS = 0.28, SSU = 1.63, SUS = 6.42, USU = 2.32, SUU = 36.75 and UUU = 52.88; where S = saturated fatty acid and U = unsaturated fatty acid. The main glycerides of the oil where S = saturated, 0 = oleic and U = linoleic plus linolenic were found to be SOO = 13.82%, OOU = 13.32%, 000 = 12.38%, OUU = 10.59% and OUS = 10.99%. The oil on fractionation by low temperature crystallization yielded two major fractions, C fraction at -10°C representing 27.95% of total oil, and D fraction, liquid at 0°C representing 44.4% of the total oil. In ASTM, fraction C had larger amounts of UUU, USU and SSU, and fraction D had larger amounts of SUU, SUS and SSS. The triglyceride composition was confirmed by quantitative fractional crystallization of the refined oil and by triglyceride determination in each fraction and calculation of the original triglycerides from the triglycerides of each fraction.

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