Purpose This study aims to investigate the effect of spray drying temperature and maltodextrin addition on the contents of phenolics, flavonoids, anthocyanins and antioxidant activities (2,2-diphenyl-1-picrylhydrazyl [DPPH] radical scavenging activity, ferric reducing antioxidant power and reducing power) of karonda powder. Design/methodology/approach Over the past few decades, the demands for application of natural colorants in food production have been attracting the attention of academic research and food industry. Anthocyanins, a red pigment commonly found on plants, show high potentials in the preparation of spray-dried pigment powder. This study, therefore, was conducted using full factorial design with two factors, namely, inlet temperature (150°C and 160°C) and soluble solid concentration (10, 15 and 20°Brix) with maltodextrin as carrier to produce pigment powder from karonda, an anthocyanin-rich fruit which is native to southeast Asia. Findings Increasing soluble solid content from 10 to 15°Brix resulted in a 42%–57% reduction in phenolic, flavonoid and anthocyanin contents. However, when increasing the amount of maltodextrin from 15 to 20°Brix, a lower reduction (approximately 11%–19%) was observed. In samples with the same °Brix, there was no significant variation in antioxidant contents and activities, especially at high maltodextrin ratios. In addition, the reducing power of samples dried at higher temperature (160°C) was higher than that of samples dried at lower temperature. Karonda spray-dried powder showed a good positive correlation (p < 0.01) between antioxidant contents and DPPH• activity. Originality/value To the best of the authors’ knowledge, in this study, for the first time, the effect of spray drying conditions on the quality of karonda powder was investigated.

Lime (Citrus latifolia) juice concentrate is rich in vitamin C and phenolic compounds exerting a range of health benefits. Spray drying converts fruit juice into powder and offers convenience for industrial applications. The appropriate spray drying conditions for lime juice prepared by freeze concentration are rarely reported. Thus, this study aimed to investigate the effects of inlet temperature (130-170°C) and feed flow rate (20-40 mL/min) on drying yield, total ascorbic and phenolic contents (TPC) of the dried lime powder from spray drying of freeze-concentrate lime juice (containing 22% solid). The inlet drying temperature influenced the yield, total ascorbic acid and phenolic contents of the lime powders. The drying using an inlet temperature of 130°C resulted in the dried lime powder with ascorbic acid and phenolic contents of 113.1 mg/100 g and 1268 mgGAE/100 g, respectively and an acceptable yield (90.1%). The most appropriate feed flow rate was 30 mL/min which resulted in lime powder with high yield, total ascorbic acid and phenolic content. In conclusion, the high-quality spray-dried powder can be processed at the 130°C inlet temperature and 30 mL/min of feed flow rate. At these conditions, the obtained powder had a 45% lime solid and suitable moisture content (4.5%) and water activity (< 0.25) that would be stable for storage.