Non-alcoholic beer production using ohmic heating assisted vacuum distillation method

In this study, non-alcoholic beer was produced with an ohmic heating assisted vacuum distillation system (ODVD) and vacuum rotary distillation (VDD). The process was carried out until the alcohol content reached legal limits (< 0.5% v/v). The processes were carried out at 100, 150 and 200 mbar in both systems and the required processing times were determined. The voltage gradients were examined at 15, 20 and 25 V/cm in the ohmic system. The aroma profile, rheological properties, antioxidant capacity (ABTS, DPPH, FRAP, TAK), total phenolic content, total flavonoid, colour, pH, vicinal diketone (VDK) and bitterness value of the samples were analyzed. Electrical conductivity values for the ohmic system were calculated and the two methods were compared in terms of energy consumption and efficiency. It has been seen that the ODVD system reduced the processing time required for the reaching target alcohol content. It has been observed that ODVD system is more advantageous than the VDD system in terms of energy efficiency and consumption. It has been found that electrical conductivity was increased with temperature increased and the voltage gradient has no effect on the change in electrical conductivity. When compared in terms of antioxidant capacity, total phenolic content, total flavonoid and VDK, it has been seen that ODVD and VDD methods were similar in some conditions. It has been observed that there are no differences in pH value between the samples but pH values were increased compared to the original beer. It has been determined that the colour and bitterness values were increased compared to the original beer and they were determined higher in the VDD compared to the ODVD. In terms of aroma profile, it has been determined that the major substances that form the characteristic aroma of beer were removed end of the process. According to rheological analysis results, it has been seen that the Herschel-Bulkley model was the suitable model for explaining the rheological behaviour. The results obtained within the scope of this study showed that the ODVD system can be used in the production of non-alcoholic beer. Keywords: Ohmic system, Non-alcoholic beer, Energy efficiency, Distillation