Suitable extractants crucial to reliable test results

An important requirement for accurate food allergen analysis is to obtain complete and unaltered protein extracts from the sample under investigation. Scientists at the University of Hamburg in Germany have compared the efficacy of 11 different extractants for the recovery of protein from milk and egg powders. Their results highlight the importance of selecting the most suitable extractant when analysing the allergenic potential of foods.

Compared with the other extraction solutions investigated in the study, the authors report that '1% Tween 20® and 0.4% Triton X-100®' and '4% SDS' are the most suitable extractants to isolate proteins of hen's egg or milk. Variation of extraction temperature did not appear to cause any changes to the efficacy of the extractants studied.

Further work carried out in the study showed significant impacts on extraction depending on the type of food matrix. While the addition of wheat starch to the sample did not influence the extraction results, using fat powder and dry cake mix led to different results. Depending on the sample, some protein recovery rates decreased and some increased when fat powder and dry cake mix were added prior to extraction.

The authors concluded the suitability of the extractant not only depends on the properties of the allergen but also on the type of matrix containing the allergen.

Reference: Steinhoff et al. 2011. Food Additives and Contaminants. Part A, Chemistry, analysis, control, exposure and risk assessment. DOI: 10.1080/19440049.2010.545957