Bioaccessibility of acrylamide in instant soluble coffee and coffee substitutes from cereals and chicory. Study on isolated samples and combined with milk

Resumen del trabajo presentado a la 8th International Conference on Food Digestion, celebrada en Porto (Portugal) del 9 al 11 de abril de 2024.

Acrylamide is a chemical process contaminant generated in foods when exposed to elevated temperatures and low moisture conditions, through the interaction between free amino acid asparagine and reducing sugars. Previous studies focused on potato and cereal-based products have demonstrated the impact of the food matrix and potential interactions between food components on acrylamide bioaccessibility. However, limited information exits for other foods. The objective of this study was to assess the bioaccessibility of acrylamide in different instant soluble coffees as well as coffee substitutes made from cereals and chicory. Additionally, the study aimed to investigate the possible influence of the mixture of coffee or substitutes with milk in the bioaccessibility of the contaminant. Using the INFOGEST protocol, samples were in vitro digested both independently and combined with milk. Acrylamide was determined by LC-ESIMS/MS in initial samples and in the bioaccesible and non-bioaccesible fractions obtained after the digestion, according to the protocol described by González-Mulero et al. Bioaccessibility ranged between 73-90% in soluble coffees and 78-99% in coffee substitutes, with recoveries of 74-99%. Simultaneous digestion of samples with milk exclusively increased acrylamide bioaccessibility and recovery in instant chicory. The high electrophilic property of acrylamide makes it prone to reacting with amino and sulfhydryl groups of different nucleophiles present in the food matrix through Michael addition reactions. Particularly, in coffee samples the interaction between acrylamide and melanoidins has been described, giving place to melanoidin-bound-acrylamide complexes. The occurrence of this phenomenon during the digestive process might account for the observed decreases in acrylamide bioaccessibility after the in vitro digestion. This circumstance did not occur in coffee substitutes containing higher cereal content, as almost all of the acrylamide remained soluble after digestion. In contrast to prior findings with biscuits-milk combinations, where a decline in acrylamide bioaccessibility occurred, the addition of milk had no impact on acrylamide bioaccessibility in instant coffee. Moreover, it even enhanced its bioaccessibility in soluble chicory. This underscores the significance of the food matrix composition in influencing the availability of the contaminant.

Peer reviewed