*4.1.1 General procedure*

The orange wastes were treated with sulfuric acid (1% w/v) at 94, 100, 140, and 180°C for 60, 30, and 0 min in order to extract pectin from the hydrolysate. The highest yield of pectin extraction was 24.7% (w/w) and 23.7% (w/w) in orange peel and pulp, respectively, in the supernatants at 94°C for 60 min. The results of FT-IR confirmed that the characteristics of the extracted pectin were similar to the commercial product. Regarding the pectin purity, the GalA content was 70.2 and 69.9% in orange peel and pulp, respectively. The acid treatment (94°C, 60 min; 140°C, 30 min) showed a DE being higher than 69% and less than 45%, respectively. At the optimal conditions, high production of pectin was 244 kg/t of orange wastes without enzyme procedure.
