Enzymatic Browning Science Fair Projects

Food Preservation

Food preservation has always been a concern for humans. Inproper methods make foods spoil or turn toxic.

EDU 7080 Detectolab Kit	EDU 8355 Super Chem Kit	EDU 8350 Super Chem Science Kit	Young Scientists Club Set 4
Ages 8 and up	Ages 10 and up	Ages 8 and up	Ages 9 - 12

Objectives/Goals

I conducted my experiment to determine which acidic fruit juice or tap water would help to best prevent enzymatic browning from occurring on the surfaces of freshly cut apple slices.

Methods/Materials

Apple slices were dipped, one per each of seven juices: apple, pineapple, orange, lemon, lime, white grape, and white grapefruit, along with tap water for five minutes. They were then removed from their respective juices and observed during four intervals occurring at 15 minutes, 3 hours, 6 hours, and 9 hours, to see what antibrowning effects the acidic juice and water had on the cut surfaces of apple slices.I developed and used a browning scale to determine my results.

Results

The apple slices soaked in lime (pH 2.38) and lemon (pH 2.49) juices consistently performed the best, in terms of inhibiting the browning of cut apples at all select intervals, while the slices soaked in less acidic juices were not as good in preventing browning. This was true, but for one exception. Orange juice (pH 3.87) dipped slices performed better than white grape (pH 3.49) and apple juice(pH 3.79) dipped slices, in spite of having a lower pH than orange juice.

Conclusions/Discussion

I have proven my hypothesis such that the acidity of a fruit juice plays an important role in inhibiting enzymatic browning of cut apples, thus apple slices dipped in low pH juices like lemon and lime, will maintain their fresh-cut apple color longer. In the case of the apple slices dipped in orange juice, I can also conclude that they maintain the fresh-cut apple color better than apple and white grape dipped slices due to the fact that orange juice is known to contain high levels of the antioxidant, ascorbic acid (also known as vitamin C), than the other two. Both ascorbic and citric acids are important factors to make note of in juices, since they are antibrowning agents. 3rd party contributor