Properties and microstructure of blackcurrant powders prepared using a new method of fluidized-bed jet milling and drying versus other drying methods

This study compared the bioactive, physical and microstructural properties of blackcurrant powders prepared by an innovative fluidized-bed jet milling and drying method (FBJD) with those obtained by freeze drying (FD), convective drying (CD) and spray drying (SD). Bioactives such as vitamin C and anthocyanins were measured by HPLC, while antioxidant activity and total content of polyphenols were measured spectrophotometrically. A scanning electron microscope was used to establish the microstructure of both fresh fruits and powders. Water activity, water-holding capacity, water solubility index and pH were also determined. Retention of total polyphenols and vitamin C in FBJD powders was 88% and 79%, respectively, and 80% for both polyphenols and vitamin C in FD powders. Taking the above into account the FBJD method was found to be comparable to the FD method and compared favorably against the commonly used CD and SD methods.