Background:
Extraction is an important step to obtain phytochemical compounds from natural
materials. Among different extraction techniques, microwave-assisted extraction (MAE) is an advanced
method with high extraction efficiency and low energy consumption.
Objective:
The aim of this study was to optimize the MAE parameters for obtaining the highest levels of
phenolic compounds and antioxidant activity from cacao pod husk (CPH).
Methods:
The dried CPH was prepared using microwave drying method. The CPH extract was prepared
using microwave-assisted extraction method. The powdered CPH extract was prepared using vacuum
evaporation and freeze drying methods. Phytochemical compounds and antioxidant capacity of CPH
extracts were analyzed using spectrophotometric methods.
Results:
The optimal MAE parameters were 600 W microwave power, 5 s/min irradiation time, 30
min extraction time, and 50 mL/g solvent to sample ratio. Under these MAE parameters, total
phenolic content (TPC), phenolic extraction efficiency (PEE), saponin content (SC), and DPPH
radical scavenging capacity (DRSC) were achieved from the CPH to be 10.97 mg GAE/g dried
sample, 76.82%, 70.10 mg EE/g dried sample, and 141.18 mg DPPH/g dried sample, respectively,
which were not significantly different from the predicted values (10.38 mg GAE/g dried sample,
72.68%, 70.09 mg EE/g dried sample, and 121.49 mg DPPH/g dried sample, respectively). The
residual moisture, water activity, density, water soluble index and pH of powdered CPH extract
were 9.72%, 0.38, 0.17 g/ml, 84.93% and 7.68, respectively. TPC, total flavonoid content (TFC)
and SC of powdered CPH extract were 15.75 mg GAE/g dried sample, 27.03 mg CE/g dried sample
and 133.67 mg EE/g dried sample, respectively. DRSC and ferric reducing antioxidant power
(FRAP) of powdered CPH extract were 227.79 mg DPPH/g dried sample and 14.12 mg Fe(II)/g
dried sample, respectively.
Conclusion:
The findings from this study reveal that the powdered extract obtained from the CPH at
the optimal MAE parameters is a rich source of phytochemicals possessing great antioxidant activity.
Therefore, it is a potential candidate to apply in the functional foods.
Technology Optimization for Microwave-assisted Extraction of Water Soluble Dietary Fiber from Peanut Hull and Its Antioxidant Activity