Studies of acrylamide level in coffee and coffee substitutes: influence of raw material and manufacturing conditions.

BACKGROUND

Many animal studies have shown that acrylamide is both neurotoxic and carcinogenic. The first reports of acrylamide actually having been found in foodstuffs were published in 2002 by the Swedish National Food Agency in conjunction with scientists from the University of Stockholm. It has since been demonstrated that acrylamide arises in foodstuffs by the Maillard reaction, ie. between free asparagine and reducing sugars at temperatures >120 degrees C. Coffee in fact, forms one of the principal dietary sources of acrylamide, where it is normally drunk in large quantities throughout many countries worldwide that includes Poland. Thus, it constitutes a major dietary component in a wide range of population groups, mainly ranging from late adolescents to the elderly.

OBJECTIVES

To determine the acrylamide level in commercial samples of roasted and instant coffee and in coffee substitutes by LC-MS/MS method. The influence of coffee species and colour intensity of coffee on acrylamide level was also detailed.

MATERIALS AND METHODS

A total of 42 samples of coffee were analysed which included 28 that were ground roasted coffee, 11 instant coffees and 3 coffee substitutes (grain coffee). Analytical separation of acrylamide from coffee was performed by liquid chromatography followed by tandem mass spectrometry (LC-MS/MS). To evaluate the colour intensity of ground roasted coffee and instant coffee we used method of arranging (sequence).

RESULTS

The highest mean acrylamide concentrations were found in coffee substitutes (818 pg/kg) followed by instant coffee (358 microg/kg) and then roasted coffee (179 microg/kg). One single cup of coffee (160 ml) delivered on average from 0.45 microg acrylamide in roasted coffee to 3.21 microg in coffee substitutes. There were no significant differences in acrylamide level between the coffee species ie. Arabica vs Robusta or a mixture thereof. The various methods of coffee manufacture also showed no differences in acrylamide (ie. freeze-dried coffee vs agglomerated coffee). A significant negative correlation was observed between acrylamide levels and the intensity of colour in roasted coffee; this was not the case however for instant coffee.

CONCLUSIONS

It was demonstrated that roasting process had the most significant effect on acrylamide levels in natural coffee, however there were no relationships found with coffee species. Due to the high acrylamide levels demonstrated in coffee substitutes, recommended amounts should be defined and manufacturers should be obliged to reduce such levels in these products.