Synergistic interaction of ascorbic acid and green tea extract in preventing the browning of fresh cut apple slices

Abstract

A novel combination of ascorbic acid (AA) and green tea extract (GTE) was tested for its ability to prevent browning of fresh cut Red Delicious apple slices. A concentration of 3% AA and 0.1% GTE was selected for definitive studies since it provided an optimum balance of antibrowning efficacy, taste, lack of staining, and cost. This combination prevented the browning of apple slices for up to 14 days; whereas, 3% AA prevented browning for only 4–6 days. In addition, GTE by itself caused noticeable staining of the apple slices; whereas, the combination did not stain the slices. Mechanistic studies demonstrated that the GTE helped to maintain AA levels, likely due to the GTE's own antioxidant and enzyme inhibition properties. In conclusion, AA and GTE exhibited a synergistic interaction in preventing the browning of fresh cut apple slices. Practical applications Fresh cut produce, such as apple slices, require a preservation method to prevent browning and premature degradation during storage. Sulfites are no longer allowed in the United States for this use and ascorbic acid requires very high concentrations for adequate and prolonged preservation. Other methods have been developed; however, they are often too complex for widespread and cost-effective use. The current research demonstrated that green tea extract dramatically potentiates the antibrowning effect of ascorbic acid and allows much lower levels of ascorbic acid to be used to achieve optimum antibrowning efficacy. In addition, complex packaging requirements are not needed to obtain the antibrowning effect. This novel formulation will allow much lower levels of ascorbic acid to be used, which will be a significant cost savings to producers and consumers.