Marinate pork with egg white, salt, pepper, cornstarch, oil, and shaoxing wine
Mix cornflour, potato starch, and salt to create flour mixture
Coat marinated pork in flour mixture
Prepare sweet and sour sauce by combining tomato sauce, sugar, apple vinegar, and oyster sauce
Cook pork until crispy and golden
Add bell pepper and pineapple cubes to the cooked pork
Pour sweet and sour sauce over the pork and vegetables
Toss everything together until well coated and serve
