EFFECTS OF LOW-OXYGEN ATMOSPHERE ON ETHANOLIC FERMENTATION IN FRESH-CUT CARROTS

Carrot (Daucus carota L.) root shreds were stored under a continuous f low of 0.5% and 2% O-2 (balance N-2) or in air for 7 days at 5 and 15 degrees C to study the regulation of ethanolic fermentation metabolism . Low-O-2 atmospheres of 0.5% and 2% caused increases in ethanol and a cetaldehyde concentrations and the activities of alcohol dehydrogenase (ADH) and pyruvate decarboxylase (PDC) compared to air. By day 3, eth anol 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-fol d; and PDC increased 4.2-, 3.9-, 2.3-, and 2.2-fold in samples at 0.5% O-2 at 15 or 5 degrees C and at 2% O-2 at 15 or 5 degrees C, respecti vely, compared with corresponding samples in air. These results indica te that ethanolic fermentation was accelerated more in the 0.5% than i n the 2% O-2 atmosphere and more at 15 degrees C than at 5 degrees C. The acceleration of ethanolic fermentation may allow production of som e ATP, which may permit the carrot tissues to survive.