Sweet & sour chicken & veg

Name: Sweet & sour chicken & veg
Prep time: 20 min
Cook time: 20 min
Total time: 40 min
Cuisine: Chinese
Ingredients: 425g can pineapple chunks, drained, juice reserved; 2 tbsp each tomato ketchup , malt vinegar and cornflour; 1 tbsp vegetable oil; 1 onion , chopped; 1 red chilli , deseeded and sliced; 1 red and green pepper , chopped; 2 carrots , sliced on the diagonal; 2 skinless chicken breasts , thinly sliced; 125g packs baby corn , sliced lengthways; 2 tomatoes , quartered; cooked rice , to serve