Effect of Asparaginase Treatment on Biscuit Volatile Compounds

Among the strategies proposed to reduce the formation of acrylamide in bakery products, the use of asparaginase is considered one of the most promising, also due to its limited impact on the sensory quality of the final product. Asparagine, the key precursor of acrylamide that is selectively hydrolysed by the asparaginase treatment, is generally not considered a major contributor to the overall flavour and colour of baked foods. This study investigates the effect of three addition levels of the enzyme asparaginase (500, 750, 1000 ASNU compared to a not added control) and three different preparation conditions (without resting time and with 15 min resting time at 20 °C or 50 °C) on asparagine content in the dough and on the formation of Volatile Organic Compounds (VOCs) and colour of shortbread biscuits. Results showed that the addition of asparaginase, at all levels, markedly reduced the asparagine content in the dough, with limited effects on the VOC profile and colour. The examined preparation conditions significantly affected the VOC profile: the application of a resting time at 20 °C tended to promote the formation of VOCs through lipid oxidation while reducing the level of many MR-related VOCs. This last effect seemed to parallel the slight reduction of the browning index observed when the resting time was applied. Results suggest that the use of asparaginase does not markedly affect the VOC profile of shortbread biscuits, thus confirming its limited effects on sensory-related quality attributes of baked foods.