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Advisor(s)
Abstract(s)
Since vegetable proteins are considerably cheaper than muscle proteins, they are frequently
used as meat extenders in order to reduce the cost of the final product. Due to several
interesting characteristics, soybean is reported to be the most widely used vegetable protein in
the meat industry. Nevertheless, soybean is included in the group of 12 ingredients potentially
allergenic, which should therefore be labelled according to the Codex Alimentarius FAO/WHO
and the European Commission (Directive 2003/89/EC). In fact, it has been described that
amounts of soy bellow 0.1% and 1% (w/w) can lead to allergic reactions in sensitive consumers
(1 ).
The analytical methods used for soybean detection in foods rely mainly on protein and DNA
analysis. However, it has been referred that protein-based methods can be significantly less
sensitive in the evaluation of thermally processed foods because of protein denaturation.
Recently, the analysis of DNA coupled with polymerase chain reaction (PCR) presents a fast,
sensitive and highly specific alternative to protein-based methods.
The aim of the present work was to develop PCR techniques able to identify soybean in highly
processed meat products. Specific primers designed for soybean detection based on the lectin
gene were used. The methodology was optimized using reference binary samples with different
known percentages of pork meat and soybean protein, prepared in the laboratory. To evaluate
the effect of thermal treatment, identical binary mixtures were submitted to heat treatment in an
autoclave at 121°C for 5 min.
Results showed that detection of soybean was successful in all raw mixtures until the level of
0.1 %. Regarding the autoclaved samples, detection was only achieved for levels ~ 0.5% of
soybean, probably due to thermally induced DNA degradation. Several commercial samples of
Frankfurt or Frankfurt like sausages were tested to detect the presence of soybean in
compliance with the label statements.
Description
Keywords
PCR Soybean Meat products
Pedagogical Context
Citation
Soares, SĂłnia; Amaral, Joana S.; Mafra, Isabel; Oliveira, M. Beatriz P.P. (2008). Polymerase chain reaction for soybean detection in heat processed meat products. In First European Food Congress. Ljubljana, Slovenia.