Effects of variety, agronomic factors, and drying on the amount of free asparagine and crude protein in chicory. Correlation with the acrylamide formation during roasting

Most thermally processed foods are affected by the Maillard reaction which leads to the formation of not only desired flavor and aroma compounds but also neoformed contaminants with probable unwanted biological effects. Among the latter, acrylamide was found to be formed from free asparagine in plant foods such as potatoes, cereals and coffee. Roasted chicory which is used as a common coffee substitute is also known to be high in acrylamide and indicative values have been proposed for this food category by the European Commission. The current study is aimed at understanding the impact of varietal selection and agronomic practices on the concentration of free asparagine, a major acrylamide precursor, in chicory roots, and the effect of these parameters on the amount of acrylamide in roasted chicory. The study showed that the concentration of free asparagine in raw chicory roots was variety- and year-dependent (from 444 to 2786mg/kg). All five varieties tested showed an increase in free asparagine level in response to increased nitrogen application. The duration of chicory cultivation and the date of harvest had limited effects which need to be further understood. The drying process reduced free asparagine concentration in chicory roots without generating acrylamide. Overall the reduction of free asparagine in the raw chicory roots tested in this study led to a significant decrease in acrylamide formation in the roasted chicory (from 11097 to 2249μg/kg). This positive correlation does not exclude the possibility that other factors such as those related to roasting conditions could be involved in the acrylamide formation.