*2.5. Antioxidant Activity*

ABTS and DPPH assays of quercetin-loaded HZ and HZ-chi/pec particles were estimated according to the method of Dong et al. and Pan et al. [24,25]. In brief, equal volumes of potassium persulfate (2.6 mM) and ABTS (7.4 mM) were mixed and allowed to react and generate ABTS+ for 12 h in the dark. After the diluted ABTS+ solution with an absorbance of 0.7 at 734 nm was mixed with samples at a volume ratio of 2:1 in the dark for 6 min, the absorbance was measured at 734 nm on Synergy H1 Microplate Reader (BioTek Instruments, Inc., Winooski, VT, USA). Likewise, after 0.1 mM DPPH in ethanol was added to samples in equal volumes and allowed to react for 30 min in the dark, the absorbance was recorded at 517 nm. The ABTS<sup>+</sup> and DPPH scavenging capacity was calculated with the help of the following equation,

$$\text{Free radical scavering capacity (\%)} = (\text{A}\_{\text{Control}} - \text{A}\_{\text{Sample}}) / \text{A}\_{\text{Control}} \times 100 \tag{3}$$

where AControl and ASample are the absorbances of the free radical solution without and with samples, respectively.
