Study on the Characteristics and Quality of Hot Air Drying of Prune

Abstract

In order to study the characteristics and quality changes of hot air drying (HAD) of prune, fresh prunes were used as raw material to investigate the quality changes under five different blanching conditions, and to investigate the changes of colour and aroma of prune during the hot-air drying process with different temperatures and air speeds. The results showed that the blanching temperature of 90 ℃ and the blanching time of 90 s could maintain better VC and anthocyanin contents (1.13, 12.42 mg/100 g) and inhibit peroxidase (POD) activity and polyphenol oxidase (PPO) activity (0.99 ∆OD470/min·mg, 0.57 ∆OD420/min·mg). The effect of drying temperature on time was more significant than that of air speed on time (P<0.05). The effect of drying temperature on time was more significant than that of air speed on time (P<0.05). The Page equation fitting revealed that 75 ℃ and 3 m/s were more suitable for hot air drying of prunes, the colour change of prunes was significantly affected by drying temperature (P<0.05), the ester content of prunes decreased and the aldehyde content increased after hot air drying, and GC-IMS showed 55 fingerprint signals. As summary, prunes were blanched at 90 ℃ and 90 s. The best quality of dried prunes was obtained under 75 ℃ and 3 m/s hot air conditions.

Keywords

• prune
• blanching
• hot air drying
• quality