Effects of processing conditions and formulation on spray drying of sour cherry juice concentrate

BACKGROUND: Sour cherries are rich in phenolic compounds possessing several health-promoting effects. Processing of sour cherry juice into powder form offers additional advantages such as increased utilization, reduced volume, easier handling and transportation. However, spray drying of fruit juices is difficult owing to their low glass transition temperatures (T_g). The aim of this study was to investigate the effects of inlet temperature (130-150°C), feed flow rate in terms of pump setting (30-50%), sour cherry content (25-50% of total dry matter) and carrier type (maltodextrin DE6, maltodextrin DE12, gum arabic) on yield, T_g and total phenolic content (TPC) of spray-dried sour cherry powder. RESULTS: Feed flow rate, sour cherry content and carrier type significantly affected yield and T_g, whereas TPC was affected by sour cherry content and carrier type. The effect of sour cherry content on yield depended on the carrier type. Although gum arabic provided better protection of phenolic content than maltodextrins, it resulted in lower average yield. CONCLUSION: Spray-dried sour cherry powder with high yield (>85%) and high T_g (60°C) was obtained using the following conditions: 150°C inlet temperature, 30% pump setting, 25% sour cherry content and maltodextrin DE12 as carrier.