Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/13/1996
Publication Date: N/A
Citation: Interpretive Summary: Fresh-cut carrots are marketed in sealed film bags and the respiration by the fresh-cut products can deplete the oxygen in the bag to below an acceptable level. Below the acceptable level, anaerobic respiration becomes significant and fermentation is initiated. We lack information on the oxygen level at which anaerobic respiration becomes excessive in fresh-cut carrots. This research showed that fermentation from anaerobic respiration becomes elevated when the oxygen level is depleted down to 0.5 percent. This elevated level was at a threshold level, thus, the oxygen level in film bags should not be allowed to be depleted below 0.5 percent. This information will be useful to the industry in developing films that allows oxygen permeation at 0.5 percent for fresh-cut carrots.
Technical Abstract: Carrot (Daucus carota L.) root shreds were stored under a continuous flow of 0.5 percent and 2 percent O2 (balance N2), or air for 7 days at 5C and 15C to study the regulation of metabolism of ethanolic fermentation. Low O2 atmosphere caused increases in the concentrations of ethanol and acetaldehyde and the activities of alcohol dehydrogenase (ADH) and pyruvate decarboxylase (PDC). By day 3, ethanol increased 38-, 25-, 13- and 9.5-fold, acetaldehyde increased 20-, 13-, 7.7- and 5.6 fold, ADH increased 7.6-, 6.3-, 3.8- and 2.7-fold, and PDC increased 4.2-, 3.9-, 2.3- and 2.2-fold in samples at 0.5 percent O2 at 15C and 5C, 2 percent O2 at 15C and 5C, respectively, compared with corresponding samples in air. These results indicate that the ethanolic fermentation was accelerated more in 0.5 percent ahan 2 percent O2 atmosphere, and at 15C than 5C. The acceleration of ethanolic fermentation may allow glycolysis to proceed because of consumption of pyruvate and allow production of some ATP which may permit the carrot tissues to survive.