Published online by Cambridge University Press: 15 October 2005
Introduction. Dried mango slices are a common snack product in Southeast Asian countries. Mashing the carotenoid-containing mango flesh and drying the puree to mango leather is a promising alternative to utilise even over-mature or small fruits and fruits with irregular size as low-cost raw materials. Within the study, the impact of blanching and air temperature (40–90 °C) on drying time and quality was investigated. Materials and methods. Drying tests were conducted using a laboratory dryer, which allowed continuous measurement of the drying rate. The quality of the mango leather was evaluated in terms of colour (CIE-Lab) and β-carotene content (HPLC). The formation of 13-cis-β-carotene isomer was used to indicate thermal β-carotene degradation. Results and discussion. Blanching degraded the β-carotene content, reduced drying time (–20%) and decreased browning reactions. Optimum drying conditions in terms of drying time, colour and β-carotene retention were determined at 80 °C. The all-trans-β-carotene content was maintained at 75% and no decrease in colour saturation (C*) was observed. As a result, it is expected that 80 °C is sufficient to inactivate carotenoid oxidising enzymes without showing significant negative thermal effects on β-carotene degradation. Higher temperatures led to severe β-carotene losses. Lower temperatures increased drying times, caused discolouration and decreased the β-carotene retention. Conclusion. With a provitamin A activity of (600 to 650) retinol equivalents (RE), mango leather is a promising source of provitamin.