Non-thermal treatments for the control of endogenous formaldehyde from Auricularia auricula and their effects on its nutritional characteristics

Abstract

To control endogenous formaldehyde (EFA) from Auricularia auricula and preserve its nutritional properties, we selected various non-thermal treatments and evaluated their effects on the removal of EFA, inhibition of γ-glutamyl transpeptidase and l -cysteine sulfoxide lyase activities, and bioactive ingredients (i.e., principal nutrients, including vitamins and taste substances). The results showed that single and co-non-thermal treatments (US-EW, IPL-EW) reduced the EFA content of A. auricula to varying degrees. Correlation and principal component analyses showed that synergistic treatment with ultrasound and electrolyzed water (US-EW) significantly reduced EFA (removal rate = 40.54%), with relatively small losses of other chemical components. The second best was treatment with intense pulsed light and electrolyzed water (IPL-EW) (removal rate = 36.27%). We constructed and validated a kinetic model for EFA removal using the US–EW treatment, and fitted a second-order kinetic equation. The optimal process parameters were as follows: ultrasound (US) frequency: 50 kHz, US power: 100 W, and available chlorine concentration of EW: 35 mg/L. These results were verified and can serve as a reliable technical reference to improve safety during the processing and preservation of edible fungi. • US-EW has the highest removal rate of EFA (40.54%). • The removal of EFA via US-EW confirmed the second-order reaction kinetic. • The optimal processing parameters for US-EW removal of EFA have been obtained. • US-EW causes the least loss in nutritional quality of A. auricula .