Portal de Periódicos da CAPES

In vitro digestibility of β-casein and β-lactoglobulin under simulated human gastric and duodenal conditions: A multi-laboratory evaluation

2009; Elsevier BV; Volume: 55; Issue: 3 Linguagem: Inglês

10.1016/j.yrtph.2009.08.010

1096-0295

Giuseppina Mandalari, Karine Adel‐Patient, Vibeke Barkholt, Cristina Baró, L Bennett, Merima Bublin, S. Gaier, Gerson Graser, Gregory S. Ladics, Dagmara Mierzejewska, Εmilia Vassilopoulou, Yvonne M. Vissers, Laurian Zuidmeer, Neil M. Rigby, Louise J. Salt, Marianne Defernez, Fran Mulholland, Alan R. Mackie, Martin Wickham, E. N. Clare Mills,

Allergic Rhinitis and Sensitization

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.