Nitric Oxide Inhibition of Alcohol Dehydrogenase in Fresh-Cut Apples (Malus domestica Borkh)

The effects of nitric oxide (NO) and nitrite treatment on alcohol dehydrogenase activity and the shelf life of apple tissue were investigated. Fresh-cut apple slices were stored for 2 days at 6 degrees C in 0.25-1% NO (v/v, balance N-2) or 100% N-2 atmospheres. Slices were also treated with 1% NO or 2 mM sodium nitrite (NaNO2) for 20 min, stored for 6 weeks in 100% N-2 at 6 degrees C, and analyzed for acetaldehyde, ethanol, and ethyl acetate accumulation, firmness, and color. Compared with N-2 or deionized water controls, treatment with 1% NO or 2 mM NaNO2 inhibited ethanol accumulation, whereas that of acetaldehyde increased. Ethyl acetate accumulation was inhibited only by NO. Slice firmness was not affected by NO or NaNO2 treatment, but slices were darker than the untreated controls. NO and nitrite may extend the shelf life of fresh-cut produce with low concentrations of phenolic compounds.