Abstract
Initially the resistance to digestion of two cow's milk allergens, β-casein, and β-lactoglobulin (β-Lg), was compared using a "high-protease assay" and a "low-protease assay" in a single laboratory. The low-protease assay represents an alternative standardised protocol mimicking conditions found in the gastrointestinal tract. For the high-protease assay, both proteins were incubated with either pepsin or pancreatin and digestion monitored by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and reverse phase-high performance liquid chromatography. The low-protease assay involved gastroduodenal digestion in the presence or absence of phosphatidylcholine (PC). Both β-casein and β-Lg were susceptible to hydrolysis by pepsin and pancreatin in the high-protease assay. In contrast, the kinetics of β-casein digestion in the low-protease assay were slower, β-Lg being pepsin resistant. During duodenal digestion, β-Lg was gradually degraded and addition of PC slowed digestion. Subsequently, the reproducibility of the low-protease assay was assessed in 12 independent laboratories by visual assessment of the gels and densitometric analysis: the inter- and intra-laboratory variability was affected by sampling and electrophoresis method employed. The low-protease assay was shown to be reproducible. Future studies will extend these findings using a broader panel of proteins.
Original language | English |
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Pages (from-to) | 372-381 |
Number of pages | 10 |
Journal | Regulatory Toxicology and Pharmacology |
Volume | 55 |
Issue number | 3 |
DOIs | |
Publication status | Published - Dec 2009 |
Keywords
- β-Casein
- β-Lactoglobulin
- Allergy
- In vitro digestion
- Physiological protocol