Title page for ETD etd-0711103-093202


Type of Document Master's Thesis
Author Khachatryan, Armen
Author's Email Address akhach1@lsu.edu
URN etd-0711103-093202
Title Random Centroid Optimization of Lutein-Enriched Oil in Water Emulsion at Acidic PH
Degree Master of Science (M.S.)
Department Food Science
Advisory Committee
Advisor Name Title
Jack Losso Committee Chair
Fred Shih Committee Member
Samuel Godber Committee Member
Keywords
  • random centroid optimization
  • emulsion
  • lutein
Date of Defense 2003-07-08
Availability unrestricted
Abstract
Age-related macular degeneration (AMD) is a physiological condition that affects the elderly, diabetic patients, and leads to loss of vision. There are no effective therapies for AMD. The role of nutrition in preventing AMD is receiving strong scientific scrutiny. Lutein and zeaxanthin have been identified as dietary strategies that can delay the onset of AMD. Consumption of at least six milligrams of lutein per day has been reported to delay the onset of AMD by as much as 43%. However, most available food sources contain such low levels of lutein that it would be difficult to meet the daily requirement. It would require 2 lbs of corn, 16 lbs of tomatoes, or one salad bowl of kale to meet the minimum daily requirement. As a result, food fortification with lutein extract is appealing to health conscious consumers.

The objective of this study was to prepare an oil in water emulsion containing at least 6 mg of lutein per serving size (one tablespoon) as a daily source of lutein. Random Centroid Optimization was applied to find the best conditions for preparing a stable emulsion. Experimental parameters included: lutein concentration (0.010-0.020 %w/w); pH (3.5-4.7); phosphatidylglycerol (0.018-0.1 %w/w); whey protein (1.5-3.5 %w/w); and corn oil (15-25 %w/w). Emulsions were prepared and turbidity measurements were determined as a function of half-life stability in minutes. Absorbance was measured at 500 nm for 10 min. The same measurements were carried out using the best values for four factors obtained from the RCO program.

Emulsion stability was evaluated by heating samples at 90 oC from 5 to 30 min to check for oil separation. Emulsion samples were also shaken at 700 rpm for 30 min. Size distribution and zeta potential of emulsion droplets were measured, using zetameter.

After 9 experiments in the first cycle and 4 experiments in centroid cycle, optimal conditions for the preparation of a stable lutein-enriched emulsion were: corn oil: 20 %, phosphatidylglycerol (0.018 %w/w), pH: 4.55, lutein concentration: (0.015 %w/w), and whey proteins concentration 2%.

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