Open the can of pineapple. Drain the pineapple juice into a cup and put the pineapple chunks aside until needed.
Add to the cup of pineapple juice the soy sauce, Chinese rice wine, ketchup, vinegar, and cornstarch. Whisk with a fork until well combined and no lumps of cornstarch remain.
Thinly slice the chicken into bite-sized pieces.
Whisk the egg white until white and fluffy then gently sprinkle in the cornstarch and Chinese Five-spice powder. Whisk again until well combined.
Add the chicken to the egg white mixture and gently combine. Put aside until needed.
Heat the oil in a hot wok.
Add the battered chicken and cook, stirring gently to make sure it doesn’t stick together.
When golden brown, remove the chicken, draining the oil back into the wok. Drain the chicken on a paper towel until needed.
Add to the hot wok the onions and bell peppers; stir fry until the onions are transparent, about 5 minutes.
Add the pineapple chunks and chicken, stirring to combine.
Slowly stir in the pineapple sauce and bring to a gentle simmer. Stir until thickened, about 2 minutes.Tip: If the sauce is not brought to a boil and simmered for 2 minutes it will not thicken correctly and the cornstarch can cause a powdery mouthfeel.