Changes in postharvest quality of Swiss chard grown using 3 organic preharvest treatments

Using storage conditions recommended for conventional chard (4 degrees C, 90% RH and 7 d), the chard treated with some organic preharvest treatments [effective microorganisms, a fermented mixture of effective microorganisms with organic matter (EM-Bokashi + EM), and an auxillary soil product) lost considerable water (> 2%) and weight (> 25%). These results indicate that organic methods tested produce a vegetable that can not sustain its quality when commercialized through the conventional supply chain. Nevertheless, respiration, color, pH, and titratable acidity practically remained constant during conservation. Ascorbic acid content was constant in chard treated with the different preharvest treatments and collected at 8 wk after sowing (normal harvest). However, the ascorbic acid content of the control chard decreased 60% after 7 d of storage. This vitamin diminished (35%) in chard collected after 19 wk after sowing (late harvest) during the postharvest conservation. The greatest difference in chard quality was registered between sampling dates since chard collected during the late harvest had higher levels of dry matter, sugars, acids, proteins, and ascorbic acid than chard collected during the normal harvest.