Inhibition of acrylamide in gluten-free quinoa biscuits by supplementation with microbial dextran

Abstract

ABSTRACT The microbial dextran (MD) as a natural bacterial hydrocolloid was used for acrylamide (AA) inhibition in gluten-free quinoa biscuits. The European council approved the use of MD as a safe functional additive in bakery products. AA was spontaneously produced during the baking of 100% quinoa biscuit dough which was quantified at 2142 ± 3 μg kg−1dry biscuit. This amount of AA in quinoa biscuits was about two times higher than the reported highest content of AA in bakery products (1044 μg kg−1) in some previous studies and six times higher than the recommended benchmark level of AA by European commission regulation in biscuits (350 μg kg−1). The effect of MD on the AA inhibition was first studied at four concentration levels (1, 3, 5, and 7%, v/v) in quinoa dough. The Leuconostoc mesenteroides NCIM-2198 synthesized MD was investigated by Fourier Transform Infrared Spectroscopy (FT-IR), 13C Nuclear Magnetic Resonance (13C NMR) and 1H NMR depicting the formation of α-(1-6) glycosidic linear chain without branches. Moreover, MD solution was a high viscous solution at pH 6.8. Interestingly, 5% (v/v) MD solution supplemented in the quinoa dough was successfully applied to inhibition rate 89.1% of AA formation (down to 233 ± 6 μg kg−1dry biscuit) without deteriorating the quality of quinoa biscuits. This is the first AA mitigation approach in quinoa biscuits with an achievable result of about half the recommended EU benchmark level of AA. This AA mitigation could be due to the ability of MD to retain water molecules during baking process. Furthermore, the presence of hydroxyl groups in MD polymer could cross-link AA via hydrogen bonding. Therefore, the MD fortified quinoa biscuits could serve as low-acrylamide and health-promoting food products.