ANAEROBIC METABOLISM OF STRAWBERRIES UNDER ELEVATED CO₂ AND REDUCED O₂ ATMOSPHERES

Changes in anaerobic products and enzymes were studied in Selva strawberries kept in air, 20% CO₂ + 80% air, 50% CO₂ + 50% air, and 0.25% O₂ + 99.75% N₂ at 5C for 1 to 9 days.
The 20% CO₂ treatment slightly increased concentrations of acetaldehyde, ethanol, and ethyl acetate.
Exposure to 50% CO₂ or 0.25% O₂ resulted in greater accumulation of the anaerobic volatiles, which was associated with a reduction in fruit flavor.
Activities of pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) were slightly increased by the elevated CO₂ and reduced O₂ atmospheres in the first 5 days.
The 0.25% O₂ treatment caused a much greater increase in ADH activity after 7 and 9 days.
Results from this research and previous studies indicate that induction of alcoholic fermentation in strawberries could be due to 1) increased synthesis of PDC and ADH; 2) activation of PDC and ADH by a decrease in cytoplasmic pH; and/or 3) increased substrate concentrations of pyruvate, acetaldehyde, and NADH.

Physiological Basis of Postharvest Technologies

D. Ke, T. El-Sheikh, M. Mateos, A.A. Kader

https://doi.org/10.17660/ActaHortic.1993.343.23