Degree Type

Thesis

Date of Award

2011

Degree Name

Master of Science

Department

Food Science and Human Nutrition

First Advisor

Tong Wang

Abstract

Abstract: Feeding Study

Adding supplements to hen feed can increase egg nutritional value. Research on astaxanthin, tocotrienols, and tocopherols indicates this compound is a potent antioxidants and provides health benefits to humans. We hypothesized that the addition of these nutrients to hen feed will result in egg yolks with increased nutrient content with minimum change in functional properties. Laying hens (W-36 breed) were fed four diets with different supplementation levels of palm toco concentrate and algae (Haematococcus pluvial is) biomass containing astaxanthin for eight weeks. Egg yolks were analyzed for physical (color and Haugh unit), chemical (fatty acid composition, phospholipids by 31P NMR, quantification of tocotrienols, tocopherols, and astaxanthin by HPLC), and functional properties (texture, emulsification, viscosity, and sensory evaluation). Feed with the highest nutrient concentration was also studied for stability of these antioxidants using the Arrhenius approach. No significant differences were observed among functional properties, except emulsification capacity and sensory characteristics among eggs from different diet treatments. Emulsification capacity decreased as the concentration of feed additives increased. Changes in egg yolk color achieved maximum values at day 8. Incorporation of tocopherols and tocotrienols increased until day 8 and astaxanthin incorporation increased until day 10, then decreased slightly thereafter. Feed nutrients resulted in a dose-response relationship of these in the egg yolk. Transfer efficiency ranged from 0-9.9% for tocotrienols and tocopherols and 7.6-14.9% for astaxanthin for their peak values. Sensory evaluation of cooked eggs showed a significant difference in perceived sulfur, fishy flavor, astringency, and lumpy levels. No significant difference was shown with dryness and hardness characteristics. Results from the Arrhenius accelerated stability study showed significant differences in shelf-life of various nutrients and such results can be used to properly formulate the feed materials.

Abstract: Artificial Oil Body Study

Egg yolk protein is a co-product from egg lecithin isolation. We hypothesize egg yolk protein and egg lecithin can be used to make artificial oil bodies (AOB) mimicking the naturally occurring oleosomes with similar stability and oil protection from oxidation. Egg yolk protein, soy protein isolate, and naturally occurring oleosomes were used for a 30-day oxidation study. Egg yolk protein and soy oleosin were also used for a 2-week accelerated oxidation test with fish oil to determine the effect of environment (pH 3 and 7) and in the presence of a pro-oxidant (0 and 50 ppm CuSO4) on lipid oxidation. Both experiments were evaluated for primary oxidation (peroxide value), secondary oxidation TBARS (2-thiobarbituric acid-reactive substances), particle size, and turbidity. Native soy oleosomes had lowest primary and secondary oil oxidation. Yolk protein created more stable AOB than soy protein isolate. All three oil bodies were not significantly different for turbidity. pH and pro-oxidant had effects on the particle size and turbidity of the accelerated 2-week oxidation, but was unable to determine statistical significance because the AOB were not stable and oil was separated from the system.

Copyright Owner

Laurie Ann Walker

Language

en

Date Available

2012-04-28

File Format

application/pdf

File Size

159 pages

Included in

Nutrition Commons

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