The Effects of Dissolved Table Sugar on the Browning of Apple Slices

Abstract

Sugar has historically been used as a food preservative. Usually, the article of food is covered in sugar either in a solid or liquid form. For example, both Akkadians and ancient Greeks would preserve fruit by mixing it with honey (Nummer, 2002; Chavis, 2019), forming what we know as a jam and/or jelly today. The preservation works because sugar is a humectant (Dowse), reducing the water content inside the food through osmosis, and interferes with enzyme activity (Scientific American, 2006). In this experiment, different concentrations of sugar were tested to see if they reduced polyphenol oxidase (PPO) oxidation - better known as browning - in apple slices. Four treatment groups were used - 250ml of tap water, 250ml of water with 1tbsp of table sugar dissolved, 250ml of water with 3tbsp of sugar dissolved, and 250ml of water with 6tbsp of sugar dissolved. Apple slices were then submerged in the sugar water treatments. The amount of browning was recorded over 24 hours based on percentage cover of browning and darkness of browning. Significant differences were found using an ANOVA test and a post hoc Tukey’s test found that the mean comparisons involving plain tap water were statistically different whereas mean comparisons between the groups with sugar water were not. This suggests that sugar is a preservative in dilute forms and that sugar concentration has little effect on fruit browning.