Prevention of browning of apples slices has been difficult to achieve because of the rapidity of the enzymatic oxidation of phenolic substrates even under reduced atmospheric pressure storage. Combinations of enzymatic inhibitors, reducing agents, and antimicrobial compounds containing calcium to extend storage life were tested to decrease the browning of Red Delicious apple slices stored at 5 and 10 degrees C under normal atmospheric conditions. Treatments were devised to prevent browning for up to 5 weeks at 5 degrees C with no apparent microbial growth using dipping solutions of compounds derived from natural products consisting of 4-hexylresorcinol, isoascorbic acid, a sulfur-containing amino acid (N-acetylcysteine), and calcium propionate. Analyses of organic acids and the major sugars revealed that the slices treated with the combinations of antibrowning compounds retained higher levels of malic acid and had no deterioration in sugar levels at 5 and 10 degrees C, indicating that higher quality was maintained during storage.

Fresh-cut banana slices were treated with pineapple juice, neutral sugars, isoascorbic acid, citric acid, other organic acids, N-acetylcysteine, 4-hexylresorcinol and mixtures of these compounds and evaluated for browning reaction. A number of other compounds previously reported to be antibrowning agents were also tested. Preliminaly tests revealed that many purported antibrowning agents, including pineapple juice, had only transitory or no effects on browning of banana slices. Subsequent replicated treatments of slices stored at 5C and 15C for 7 days showed that of the several treatments, those using citric acid and N-acetylcysteine were highly effective at reducing browning. Reflectance measurements taken immediately after treatment, after 2 days of storage, and at the end of the 1 week storage period confirmed that a mixture of 0.5 M citric acid and 0.05 M N-acetylcysteine provided the best protection against browning at both temperatures. No microbial decay was observed during the 7 day period studied.Browning can be due to enzymatic activity, oxidation of potentially antimicrobial 'Mention of a trademark, warranty, proprietary product, or vendor does not constitute a guarantee by the U.S. Dept. of Agriculture and does not imply its approval to the exclusion of other products or vendors that also may be suitable. hmoline@asrr.arsusda.gov2Address inquiries to Dr.

During a study of the ameliorative effects of methyl jasmonate (MJ) on chilling injury to vegetables, a decrease in the rate of deterioration of treated fresh-cut segments was noticed, along with an apparent decrease in microbial growth. This study showed that MJ vapor from a 10-4 or 10-5 mol source in a 1 L container retarded deterioration of celery sticks for 2 weeks at 10 °C. The number of bacterial colonies was reduced to 1/1000 of control after 1 week of storage. A MJ emulsion applied as a dip at 10-4 or 10-5 mol/L retarded deterioration of green pepper strips for 2 weeks at 10 °C. The number of bacterial colonies was reduced to 1/1000 of control also after 1 week of storage and, in particular, the appearance of soft rot was retarded by the jasmonate treatment. Measurement of the amount of MJ vaporized during storage was done by use of a [3H]jasmonate internal standard. Less than 1 × 10-6 mol of MJ vapor was necessary to cause the biochemical changes in the stored vegetables resulting in prolonged storage life and decreased microbial growth. Keywords: Celery; green peppers; methyl jasmonate; microbial contamination