Title
Detection of soy proteins in processed foods: Literature overview and new experimental work
Author
Koppelman, S.J.
Lakemond, C.M.M.
Vlooswijk, R.
Hefle, S.L.
TNO Voeding Centraal Instituut voor Voedingsonderzoek TNO
Publication year
2004
Abstract
Several tests for the detection of soy proteins in foods have been described in the literature, and some are commercially available. This article gives an overview of these methods and discusses the advantages and disadvantages of each individual method. Based on the conclusions of this inventory, an experimental approach was designed to improve the sensitivity of measuring soy protein in processed foods. The aimed sensitivity is 10 ppm (10 μg soy protein in 1 g solid sample), which is over 100-fold lower than presently available tests. The aimed sensitivity is this low because levels of food allergens at 10 ppm and above may provoke reactions in food allergic persons. Native soybean meal, soy protein isolate, soy protein concentrate, and textured soy flakes were used as test materials. Several extraction procedures were compared and a new method using high pH was selected. Polyclonal antibodies were raised in rabbits and goats, and immunopurified antibodies were used in sandwich and inhibition enzyme-linked immunosorbent assay (ELISA). Extraction at pH 12 resulted in good yields for all tested samples, both quantitatively (Bradford) and qualitatively by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Immunopurified rabbit antibodies against this extract used in a competition ELISA format resulted in a sensitive test with a detection limit of 0.02 μg/mL, corresponding to 0.4 μg/g (0.4 ppm) in food samples. Cross-reactivity with some main food ingredients was measured and appeared to be negative in all cases. The presently developed test is applicable for soy ingredients and soy-containing foods that are processed in different ways. The limit of quantitation is 1 ppm, which is an enormous improvement over earlier described methods.
Subject
Nutrition
Food technology
Chemical reactions
Concentration (process)
Food processing
Heat treatment
pH effects
Sandwich structures
Sensitivity analysis
Enzyme-linked immunosorbent assay (ELISA)
Food ingredients
Processed foods
Soy products
Proteins
Proteinase inhibitor
Soybean protein
Classification
Enzyme linked immunosorbent assay
Food analysis
Human
Immunology
Protein denaturation
Review
Enzyme-Linked Immunosorbent Assay
Food Analysis
Humans
Protease Inhibitors
Protein Denaturation
Soybean Proteins
Capra hircus
Glycine max
Oryctolagus cuniculus
To reference this document use:
http://resolver.tudelft.nl/uuid:208d326b-e4ba-446b-a1e0-be53cbd28326
TNO identifier
238076
ISSN
1060-3271
Source
Journal of AOAC International, 87 (6), 1398-1407
Document type
article