EXTENDING STORAGE LIFE OF FRESH-CUT APPLES USING NATURAL PRODUCTS AND THEIRDERIVATIVES

Authors: Buta, Joseph - George; Moline, Harold; Spaulding, David; Wang, Chien

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Fresh-cut produce is a growth industry, responding to increasing consumer demand for an ever greater and more diverse supply of salad bar and other fresh-cut items. Like other segments of the fresh fruit and vegetable industry, companies involved in the preparation and marketing of fresh-cut items are concerned about producing new items for this expanding market. A major limiting factor to accomplishing increased product diversity is the need for development of methods to eliminate browning of products after they are cut. We have shown that apple slices can be held for as long as 5 weeks at cool temperatures after being treated with combinations of nontoxic common food additives. This simple treatment provides a means to add sliced apples and possibly other highly perishable fruits to the growing fresh-cut market without using special packaging technology. Fresh-cut apple slices were treated with mixtures of isoascorbic acid, amino acids, 4-hexylresorcinol, calcium chloride and other calcium salts. A number of other compounds previously reported to be antibrowning agents were also tested. Preliminary tests revealed that many purported antibrowning agents had only transitory or no effects on browning of apple slices. Subsequent replicated treatments of slices stored at 5C and 15C showed that of the several treatments, those using isoascorbic acid, 4-hexylresorcinol and N-acetylcysteine were highly effective at reducing browning. Reflectance measurements taken immediately after treatment, after 2 days of storage, and weekly until the end of the storage period confirmed these observations.

Technical Abstract: 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 10C under normal atmospheric conditions. Treatments were devised to prevent browning for up to 5 weeks at 5C 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 no deterioration in sugar levels at 5 and 10C, indicating that higher quality was maintained during storage.