Evaluation of drying technologies for muscadine pomace to produce an antioxidant-rich functional food ingredient
MetadataShow full item record
Vacuum belt drying (VBD), freeze drying (FD) and hot air drying (HA) for dehydration of muscadine pomace were evaluated. The criteria of comparison were total phenolic content (TPC), antioxidant activity (AA), water activity and moisture content. The effect of sample thickness on the drying time was also investigated. The pomace discs of two thicknesses (4±0.5 and 2±0.3 mm) were dried for 16 time-temperature combinations for VBD (60 and 90 min; 60-120°C), 12 time-temperature and air velocity combinations for air dying (180 and 240 min; 70 and 80°C; 0.2, 0.4 and 0.6 m/s) and one for freeze drying. In lyophilized samples, TPC and AA were found to be 582.52 and 607.53 μmolGAE/g extract and 2.21 and 2.29 mmol Fe2+eq/g extract for 2±0.3 and 4±0.5 mm thickness, respectively. TPC and AA of TV1, TV2, and TH2 for 2 mm thickness and TV9, TV1, TV8, TV7, TV3, and TV15 for 4 mm thickness were found to be not significantly different (p > 0.05) from lyophilized samples. These results indicate that VBD is a promising drying technique.