Effects of dried seeds and black olives as enrichment ingredients on acrylamide concentration in savoury biscuits

Seeds and table olives are often processed with heat and chemical treatments to improve sensory and shelf-life. However, this can lead to the presence of acrylamide (AA), a potentially carcinogenic compound regulated by EU Regulation 2017/2158. These foods are often consumed as such and also as ingredients in various products, leading to concerns about human exposure to AA. The aim of this study was to investigate the effects of sesame and sunflower seeds as well as black olives with and without brine as enriching ingredients in savoury biscuits on the final AA concentration. Although these ingredients are known to contain AA and precursors, their contribution to AA formation when added to a complex matrix has not been studied. Factors like moisture, particlesize and the composition of these ingredients can either promote/inhibit AA formation. In this research, biscuits were prepared with 10% of the enrichment ingredients to mimic commercially available recipes. All enrichment ingredients and biscuits were tested for AA and some parameters such as moisture, water activity, weight loss, pH, colour and texture. The results showed that enriched savoury biscuits had significantly higher AA concentrations (+163%) than the control one (198.9 μg/kg). The sunflower seeds enriched biscuits significantly exceeded the established AA benchmark value of 400 μg/kg (EU Reg. 2017/2158). Comparison of the AA concentrations in each ingredient with those in the corresponding biscuits showed that the olives, despite their higher AA content, resulted in a smaller increase in AA (+7%) compared to seeds (+260%). This indicates that olives played a role in attenuating AA formation in biscuits. In summary, it is difficult to predict the AA content in bakery products knowing only the AA concentration in the ingredients used. In complex recipes, other factors must also be taken into account to understand how the components interact during the processing stages.