INHIBITION OF MUSHROOM BROWNING

Postharvest browning of mushrooms is a rapid process, resulting in decreased commercial value.
The process may be initiated by enzymatic oxidation of phenols such as tyrosine, to form brown pigments (melanin) or by non-enzymatic phenol oxidation induced by different factors, including bacteria.
Plant extracts and their active constituents, possessing potent tyrosinase inhibitory activities, previously isolated in our group, were tested for their ability to inhibit mushroom browning.
Sliced mushroom caps were treated with different concentrations of licorice root extract, or with 3-(2,4-dihydroxyphenyl propionic acid) -DPPacid (isolated from fig leaves), with or without pretreatment with H₂O₂, and then stored at 20°C for two days.
Browning was inhibited with an IC50 of 0.1 ppm for licorice extract and 0.18 ppm for DPPacid, without H₂O₂ pre-treatment.
Treatment of whole mushrooms with either licorice or DPPacid did not prevent browning, whereas treatment with 5% H₂O₂ prevented intact cap browning for 10 days at 4°C. This treatment caused an immediate decrease by three orders of magnitude in the number of colony forming units (CFU), from 491 to 0.37 CFU/Cm². In conclusion, increased shelf life of intact mushrooms might be achieved by treatment with H₂O₂ followed by DPPacid or for cut mushrooms by licorice extract or DPPacid alone.

V International Postharvest Symposium

O. Nerya, R. Ben-Arie, O. Danai, S. Tamir, J. Vaya

Agaricus bisporus, post-harvest treatments, polyphenol-oxidase inhibitors, hydrogen peroxide, Glycyrrhiza glabra, Ficus carica

https://doi.org/10.17660/ActaHortic.2005.682.253