Comparison of different drying technologies for brocade orange (Citrus sinensis) peels: Changes in color, phytochemical profile, volatile, and biological availability and activity of bioactive compounds

This study evaluated the effects of freeze drying (FD), heat pump drying (HPD), microwave drying (MD), and far -infrared drying (FID) on the quality of brocade orange peels (BOPs). Although the most attractive appearance, maximum levels of ascorbic acid (0.46 mg/g dry weight (DW)), carotenoids (total 16.34 & mu;g/g DW), synephrine (15.58 mg/g DW), limonoids (total 4.60 mg/g DW), phenols (total 9142.80 & mu;g/g DW), and antioxidant activity were observed in FD-BOPs, many aroma components in FD-BOPs were in the minimum levels. HPD-, and MD-BOPs depicted similar trends to FD-BOPs, but they contained the highest concentrations of limonene and & beta;-myrcene. Phenols and ascorbic acid in MD-BOPs generally featured the highest levels of bioavailability, being to 15.99% and 63.94%, respectively. In comparison, FID was not beneficial for the preservation of bioactive compounds and volatile. Therefore, considering time and energy costs, HPD and particularly MD are more appropriate for the commercial production of dried BOPs.

Automated summary

This study evaluated the effects of different drying methods on the quality of brocade orange peels (BOPs). Freeze drying (FD), heat pump drying (HPD), microwave drying (MD), and far-infrared drying (FID) were compared. The results showed that FD-BOPs had the best appearance and highest levels of certain compounds, while HPD and MD-BOPs had the highest concentrations of limonene and β-myrcene. MD-BOPs also had the highest bioavailability of phenols and ascorbic acid.