
Pineapple purée is blended, strained pineapple flesh with a thicker, pulpier body than pineapple juice.
Blitz canned or fresh pineapple chunks smooth for a same-measure swap; with juice alone, keep the measure and accept a thinner sour, or shorten the shake. Body is what separates it from juice, and body is what a thinner substitute cannot give — a sour built on it comes out without its weight. Sweetened tubs are common, so taste before you count the syrup.
Sweetened vs unsweetened purée
Commercial purée usually comes with sugar in it, and the recipe does not know that; take one and cut the sugar in the drink, or it goes cloying.
Pineapple juice
Juice is the fruit with the flesh strained out: flavor and acidity, no body at all. It will not stand in one for one: a drink that wanted the purée for texture comes out thin on juice, and thickness was the whole reason the purée was named.
Ferments and separates fast — keep refrigerated and use within a couple of days.