| Abstract
| - The low prices of some nonmilk proteins make them attractive as potential adulterants in dairyproducts. An optical biosensor (BIACORE 3000) was used to develop a direct and combined biosensorimmunoassay (BIA) for the simultaneous detection of soy, pea, and soluble wheat proteins in milkpowders. Affinity-purified polyclonal antibodies raised against the three protein sources wereimmobilized in different flow channels (Fcs) on the biosensor chip (CM5). Dissolved milk powderswere injected (20 μL injections at 20 μL min-1) through the serially connected Fcs, and the antibody-bound plant proteins were detected directly. The total run time between samples, including aregeneration step with 5 μL of 10 mM HCl, was 5 min. The limits of detection in milk powder werebelow 0.1% of plant protein in the total milk protein content. The antibodies also recognized someproteins from other plant sources, which made this BIA even more suitable as a broad screeningassay for nonmilk proteins. Keywords: Plant proteins; soy; pea; soluble wheat proteins; milk powder; direct biosensorimmunoassay; surface plasmon resonance; BIACORE
|
