Combination of PEF and Aureobasidium pullulans treatment on acrylamide mitigation in potato crisps

According to the new EU Regulation (2017/2158), which has established new “mitigation measures and benchmark levels for the reduction of acrylamide in foods”, there is the necessity to adapt different process methods in order to reduce the acrylamide formation in deep-fat fried potato-based products, and at the same time to maintain the quality of final products acceptable. Among strategies suggested for the reduction of acrylamide in potato crisps, pulsed electric fields (PEF) represent a promising innovative technology with the potentiality to remove Maillard reaction substrates, such as reducing sugars and free asparagine, in raw potato tissues. Recently, it has been reported that the strain L1 of the yeast Aureobasidium pullulans has the ability to assimilate asparagine in food systems. On the basis of this consideration, the aim of the study was to evaluate the possibility of the reduction of acrylamide content in potato crisps, pre-treating the raw material using a combination of PEF treatment to enhance the extractability of asparagine and a subsequent treatment with aqueous suspension of the aforementioned yeast. Potato tubers (Solanum tuberosum, var. Lady Claire) were manually peeled and sliced and submitted to PEF pre-treatment using a lab-scale unit delivering rectangular shape pulses. An electric field strength of 1.5 kV/cm and 1000 pulses were used. Consequently, PEF-treated samples were soaked in 250 ml of L1 water suspension (108 cells/ml) for different times at 25 C. A commercial deep-fat fryer was used for the frying tests. Fried potato crisp samples were analysed for moisture, asparagine content, colour, texture, oil uptake and acrylamide content. Results showed a significant reduction of asparagine content and therefore of acrylamide formation after frying. PEF pre-treatment of raw potato slices allowed the cell de- compartmentalisation enhancing the sugars and asparagine availability and so their assimilability from yeasts.