MICROENCAPSULATION OF CHESTNUT SEEDCOAT’S WATER EXTRACT BY SPRAY DRYING

Chestnut seedcoats were extracted per the extraction conditions defined by Central Composite Design which was considering extraction temperature (65-95°C) and time (15-90 min). Total phenolic content (TPC) of the extracts was used as response to determine optimum extraction condition(s), estimated as 95C for 65 min with the maximum TPC of 357.7 mg/g. The Box-Behnken response surface methodology was used to optimize the processing of spray drying. The independent variables used were the wall material ratio (5-20 %), MD:AG ratio and the inlet temperature (150-180 °C) whereas the responses were the product yield (PY) and the TPC of the microcapsules. The optimum spray drying conditions, simultaneously maximized the PY (69.62%) and TPC (272.52 mg/g), were determined as the wall material ratio of 12.5%, MD:AG ratio of 75:25 and the inlet temperature of 164C. The microcapsules, produced at optimum conditions, were also analyzed for their moisture content (3.2%), water activity (0.255), bulk density (0.32 g/cm3), color (Hunter L=58.72, a=11.27, b=22.94), hygroscopicity (10.92%), solubility (79.88%), particle size (6.52 μm), total antioxidant activity (0.46 g/mg DPPH) and total flavonoid content (39.99 g/mg DPPH).