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Title: NOVEL BROWNING INHIBITOR FORMULATION FOR FRESH-CUT APPLES

Author
item PILIZOTA, VLASTA - J.J. STROSSMAYER UNIV.
item Sapers, Gerald

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2004
Publication Date: 4/1/2004
Citation: Pilizota, V., Sapers, G.M. 2004. Novel browning inhibitor formulation for fresh-cut apples. Journal of Food Science. 69(4):140-143.

Interpretive Summary: Fresh-cut apples are subject to browning, especially in residual core tissue on slices, and must be treated with a browning inhibitor to prevent shelf-life limiting discoloration. This product may contain living microorganisms including human pathogens such as Listeria monocytogenes. Preliminary studies indicated that L. innocua, a related species, cannot survive in an acidic browning inhibitor solution. Our objective was to develop an acidic browning inhibitor formulation for fresh-cut apples that was effective in preventing discoloration. Granny Smith and Fuji apple slices were treated with acidic or neutral pH browning inhibitor dips and with an acidic dip containing sodium hexametaphosphate. Samples were packaged in sealed pouches and were observed during storage at 4 and 10 degrees C for the onset of browning. An acidic dip containing ascorbic acid (vitamin C), citric acid and sodium hexametaphosphate was able to suppress such browning for at least 3 weeks at 4 degrees C while comparable neutral and acidic formulations without hexametaphosphate failed within 1 week. Tissue injury, a result of some phosphate-treatments, was observed only at 10 degrees C, coincident with onset of core tissue browning. These results demonstrate that browning in fresh-cut apples can be controlled effectively with a browning inhibitor formulation unlikely to support survival or growth of Listeria.

Technical Abstract: Fresh-cut apples are subject to enzymatic browning, especially in residual core tissue, and must be treated with a browning inhibitor to prevent this shelf-life limiting discoloration. This product does not receive a "kill" step and may contain viable microorganisms including human pathogens such as Listeria monocytogenes. Preliminary studies indicated that L. innocua could survive in a neutral browning inhibitor solution but not when the solution was acidified. Our objective was to develop an acidic browning inhibitor formulation for fresh-cut apples that was effective in preventing core tissue discoloration. Granny Smith and Fuji apples were cored and cut into wedges, treated with acidic or neutral pH browning inhibitor dips, or with an acidic dip containing sodium hexametaphosphate. Samples were packaged in pouches to produce a modified atmosphere and observed during storage at 4 and 10 degrees C for onset of core tissue browning. A pH 2.9 dip containing ascorbic acid, citric acid and sodium hexametaphosphate was able to suppress such browning in both apple varieties for at least 3 weeks at 4 degrees C, while comparable neutral and acidic formulations without hexametaphosphate failed within 1 week. Tissue breakdown, a result of some phosphate-treatments, was observed only at 10 degrees C, coincident with onset of core tissue browning. These results demonstrate that browning in fresh-cut apples can be controlled effectively with a browning inhibitor formulation unlikely to support survival or growth of Listeria.