Effect of pretreatments and drying methods on the quality of dried mango (Mangifera Indica L.) slices

Abstract

The present study was conducted to assess the effect of some pretreatments and drying methods on the qualities of dried mango slices. Four pretreatments (lemon juice, salt solution dips, hot water blanching and control) and four drying methods (solar, tray, freeze and fluidized bed drying) were considered and arranged in factorial experimental design. The proximate composition, physicochemical properties, antioxidants and colour were evaluated. The result showed that the pretreatments and drying methods showed significant effects on the proximate composition, physicochemical properties, and color, antioxidants of the dried mango slices. The nutrient analysis showed that mango slices had respective ranges for moisture, protein, fat, fibre, ash and carbohydrate contents (5.63–9.91%, 2.49–2.71%, 2.89–3.16%, 6.51–6.56%, 2.66–2.73% and 75.51–79.35%). The pH, TSS, TA, and hardness of the dried mango slices, respectively were 3.17–3.68, 69.36–86.29ºBrix, 2.20–2.54 g/100 g and 7.27–15.63 N. The ascorbic acid and phenol contents were affected by drying methods and had respective values of 33.18–41.24 mg/100 g and 131.13–251.12 mg/100 g; these indicate all dried mango slices were good source of nutrition and antioxidants. These findings suggest the freeze and fluidized bed driers after subjected to the pretreatments as the best method for the drying of mango in terms of ascorbic acid and colour preservation. In conclusion, these results indicate that drying technology has an enormous potential to reduce the postharvest of mango in Ethiopia that is estimated between 25-40%.