“…Peel was the most used by-product (Ahmad et al, 2013;Muhtadi et al, 2015;Liu et al, 2016;Ahmed et al, 2017;Ashraf et al, 2017;Fayek et al, 2017;Luka et al, 2017;Gosslau et al, 2018;Sathiyabama et al, 2018;Srivastava, 2018;Mayneris-Perxachs et al, 2019;Rekha et al, 2019), and some studies also used seed (Chilaka et al, 2015) and bagasse (Macagnan et al, 2015). In most research studies, an extract from the by-product was used, including methanolic, alcoholic, hexane, hydroethanolic, and aqueous extracts, whereas in other studies, a part of the by-product was obtained, for example, pectin from orange peel.…”