Optimization of Immunoglobulin (IGY) Extraction from Selected Avian Eggs Using Potato and Wheat Starches

Lim, Yu Rong (2025) Optimization of Immunoglobulin (IGY) Extraction from Selected Avian Eggs Using Potato and Wheat Starches. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

Text LIM YU RONG_Full Text.pdf Restricted to Registered users only Download (1MB)

Abstract

Immunoglobulin Y (IgY) is the predominant antibody in avian species, providing a non-invasive, ethical alternative to mammalian antibodies for diagnostic, therapeutic, and food safety applications. The extraction of IgY from egg yolks is challenging due to the high lipid content, which makes up 33% of the whole egg yolk. Conventional methods often use harsh chemicals such as chloroform or polyethylene glycol, posing environmental and safety concerns. This study aimed to optimize IgY extraction by using potato and wheat starches as biodegradable delipidation agents, comparing their efficacy across chicken, duck, and quail egg yolks at 0.01% and 0.2% concentrations. Egg yolks were diluted with starch suspensions for lipid removal, followed by centrifugation and salt precipitation to isolate IgY. Concentrations were measured using NanoDrop spectrophotometry at 280nm with an extinction coefficient of 1.33. Purity of samples containing IgY was assessed via SDS-PAGE, with band intensities semi-quantified using ImageJ software. Analysis revealed that extraction using wheat starch at 0.01% concentration resulted in the highest overall mean IgY yield among the tested egg types. Chicken eggs exhibited the greatest mean concentration (9.4 mg/mL), while quail and duck eggs showed comparatively lower mean values of 3.2 mg/mL and 3.1 mg/mL, respectively. SDS-PAGE confirmed IgY bands at ~65-70 kDa (heavy chain) and ~20-25 kDa (light chain), alongside a ~45 kDa band (truncated heavy chain) in duck samples. ImageJ analysis revealed integrated densities reflecting relative IgY abundance, with the highest overall mean integrated density for chicken using potato starch 0.01% (combined heavy and light chain density: 7.7 × 104) and wheat starch 0.01% (combined density: 5.1 × 104). The results suggest that a 0.01% starch concentration enhances IgY yield across species. However, while chicken and duck egg yolks exhibited higher yields at 0.01% concentration across both starches, quail egg yolk demonstrated a slightly higher yield at 0.2% concentration using wheat starch. These findings indicate that while both potato and wheat starches are effective delipidation agents for IgY extraction, IgY yield varies by species, with chicken eggs exhibiting the highest yield, followed by quail and duck eggs.