Prepare an ice bath.
To make the sorbet syrup, mix 35 g of the castor sugar with the stabiliser. Place the remaining 315 g castor sugar with the water and glucose powder in a pot and heat to 40°C, stirring continuously using a whisk. Slowly pour in the sugar/stabiliser mixture, stirring all the time. Continue stirring until the mixture reaches 85°C.
Remove from the heat and transfer the mixture to an ice bath. Allow the mixture to cool completely.
To make the sorbet, add the 320 g cooled sorbet syrup to the pineapple purée and water and mix. Once combined, allow the mixture to mature for at least 3 hours, to give the stabilisers and sugars time to bind. Churn the sorbet in an ice cream machine. Store at –10°C in the freezer.