Quality and Consumer Acceptance in Relation to Post-Harvest Browning of Cultivated Mushrooms

Abstract

Colour of mushroom is the major factor in the decision to purchase fresh mushrooms. Consumer acceptance, preference and pricing of a colour range of mushrooms was established. White, as opposed to brown, mushrooms were preferred, the whiter the higher the price paid. The precropping environmental conditions have been related to post-harvest browning. Climatic cabinets were used as growing units. White strain mushrooms grown in a wet environment (low evaporation 94% RH) significantly browned more on storage compared to mushrooms grown in a dry environment (high evaporation, 83-85.5% RH). Bruising on harvest measured by a bruising comparator indicated the same trends. No significant differences were found between the two environments for an off-white strain except in respect of bruising. Mushrooms from the wet environment bruised more. A significantly higher yield was obtained from the wet environment for the white strain grown. No significant differences were found for the off-white strain. Surface browning was measured using an EEL reflectometer. Percentage reflectance was correlated to subjective gradings (p<0.001) throughout experiments. The surface features of mushrooms were examined using a Scanning Electron Microscope (SEM). The SEM was not satisfactory for determining differences between strains and effect of environment on strains. Structural differences between unblemished, bruised, blotched and scaled tissue were established. The effect of mechanical injury (caused by farm handling procedures) on post-harvest browning was studied. No satisfactory conclusions could be drawn. Mushrooms surface wet and packed into baskets browned more on storage compared to surface dry mushrooms. The effect of electron irradiation (3MeV) on post-harvest browning was examined. Overwrapped and uncovered prepacks of mushrooms were irradiated with 0, 50, 100, 200 and 400 Krad. No differences were found.