**7. How does ultrasonic pretreatment affect the performance of pectin from ultrasonic-enzymatic extraction?**

"Studies show that the use of ultrasound before treatment with extraction fluid containing enzymes increases the performance of the extracted pectin and also reduces the extraction time. For example, With ultrasonic pretreatment for

15-45 minutes and then treatment with enzymatic extraction fluid for 60 minutes, the yield of pectin shows an increase of about 84-92%. If the enzyme-containing extraction fluid treatment is applied for 120 minutes and the ultrasonic pretreatment is applied for 15-45 minutes, the yield of pectin increases by 67-95%. In addition, if ultrasonic pretreatment is performed for 15-45 minutes and then treated with enzymatic extraction solution for 240 minutes, the pectin yield will not increase significantly (2-16%). The increase in yield of isolated pectin by the ultrasonic treatment is due to the intensification of mass transfer by sonication due to cavitation bubble collapse, which facilitates penetration of the enzymes into the plant tissue because of the increase in porosity and surface area. Ultrasonic applications cause cell swelling and softening of the walls, and by hydrating the pectin in the inner layer, they break down the walls during the process and facilitate the release of pectin" [4].
