Determination of nut varieties and their detection in festive cookies by MALDI-TOF mass spectrometry

Rationale

Nuts contain a large amount of essential fatty acids, amino acids, and whole range of minerals and vitamins valuable for human health, yet certain risks are associated with their consumption, of which allergic reaction is the most important. Considering the growing number of people suffering from allergies caused by allergens of protein origin, the aim of this work is to find out whether nuts can be distinguished from each other on the basis of contained proteins.

Methods

A total of eleven raw and subsequently heat-treated nuts (almonds, Brazil nuts, cashews, coconuts, hazelnuts, macadamia nuts, peanuts, pecans, pine nuts, pistachios, and walnuts) were analyzed using MALDI-TOF (matrix-assisted laser desorption/ionization time-of-flight) mass spectrometry with the subsequent finding of characteristic m/z values for each analyzed nut. No previous method for protein extraction was used.

Results

The characteristic values were used to verify the composition of seven types of festive cookies – six commercial products and one “unknown” cookie, where it was not known in advance, which nut it was made from.

Conclusions

The procedure, together with the found characteristic m/z values, could serve to rapidly identify the plant origin of nut products.