Influence of Pretreatment and Temperature on Vitamin C Content of Dried African Star Apple Fruit

Abstract

The African star apple (Chrysophyllum africanum), a tropical fruit widely consumed for its sweet pulp has been found to be a rich source of vitamin C. Due to its seasonal nature and high spoilage rate, which contributes to environmental waste, processing is essential to make it available off-season. The fruits were washed, sorted, deseeded, and diced into 2 mm pieces, after which four
selected pretreatment techniques [hot water blanching (80 ℃ for 3 min), steam blanching (100 ℃ for 1 min), salt solution (1:25 w/v), and sugar solution (60 ºBrix)] were applied. Untreated samples were used as control samples. All samples were then dried using an oven dryer and an electric dehydrator at temperatures of 45, 55, 65, and 75 ℃, monitored at intervals until a constant weight
was achieved. Throughout the experiment, the vitamin C content of the samples were measured using standard methods, similarly, the effect of pretreatment and drying temperature on the rate of vitamin C degradation was thoroughly assessed throughout the drying process. Significant differences were noticed in vitamin C retention across all pretreatment techniques employed. The
vitamin C content of the fruit dropped from 56.38 mg/100 g in the fresh fruit to as low as 7.08 and 7.17 mg/100 g after oven drying and electric dehydration, respectively. Steam pretreatment at 55 ℃ yielded the best results in terms of vitamin C retention. Therefore, steam pretreatment has the potential to preserve the quality of dried fruits.