Pulsed electric field extraction of valuable compounds from white button mushroom (Agaricus bisporus)

• Significant increase in extraction yields of polysaccharides, polyphenols and protein in Agaricus bisporus were observed by using Pulsed Electric Field combined with mild heating when compared to thermal extraction.
• Following PEF extraction of white button mushroom , polysaccharides, polyphenols and protein concentration in the extracts increased with the increase of electric field intensity, temperature and treatment time.
• The extraction studied is energy efficient since the treated suspension of mushroom has low electrical conductivity, which minimised ohmic heating, suggesting that this innovative extraction process could be applied commercially.

The effect of continuous PEF treatment on the extraction of white button mushroom suspension (9% w/w) was studied. Pulsed electric field intensity in the range of 12.4 to 38.4 kV/cm was applied with bipolar square pulses of 2 μs pulse duration. The optimum extraction yields 98% ± 0.10 (7.9 mg/g mushroom) of polysaccharide, 51% ± 0.07 (1.6 mg GAE/g mushroom) total polyphenols, and 49% ± 0.09 (2.7 mg/g of mushroom) proteins were estimated after exposing the mushroom suspension to electric pulses of 38.4 kV/cm field intensity for 272 μs and a treatment temperature of 85 °C. On the other hand, conventional extraction of 9% w/w mushroom suspension at 95 °C for 1 h obtained yield of only 56% ± 0.06 (6.4 mg/g mushroom) polysaccharide, 25% ± 0.03 (1.3 mg GAE/g mushroom) total polyphenols, and 45% ± 0.10 (2.6 mg/g of mushroom) proteins. The yield of conventional extraction operated at the same temperature and for few minutes was negligible for all of these compounds. This concludes that the extraction enhancement of PEF is not exclusively due to the ohmic heat generated during PEF treatment, suggesting a synergistic effect of electric pulses and temperature on the extraction performance.Industrial relevanceExtraction is commonly used in the industry to extract valuable compounds using chemical or thermal methods. Extraction using pulsed electric field has the benefit of minimising any damage to the extracted nutrients from any product.