*2.6. Antioxidant and Antibacterial Assays*

Antibacterial properties of chitin suspensions were tested on treated tissues according to the BS ISO 8784-1:2014 Standard for determining the total number of colony-forming units of bacteria on disintegration on at least 5 plates.

The measurement of the radical scavenging activity (RSA) of polyphenols was performed according to the DPPH assay, as a simple and widely used method to determine the antioxidant properties of active molecules [73]. The analysis was conducted on an aqueous solution of polyphenols at concentrations of 0.07 wt%, 0.3 wt%, and 3 wt% to verify their antioxidant activity. The analysis was performed on three samples for each concentration. The absorbance of reference and sample solutions was measured with a UV-VIS spectrophotometer Perkin Elmer L60000B (Perkin Elmer, Waltham, MA, USA). The RSA was calculated as reported in Equation (1):

$$\text{RSA(\%)} = \left[ (\text{A}\_{\text{reference}} - \text{A}\_{\text{sample}}) / \text{A}\_{\text{reference}} \right] \times 100 \tag{1}$$
