Involved in the biosynthesis of volatile esters which confer ripe apple fruit flavor (By similarity). Alcohol acyl transferase that can use a wide range of alcohols as substrate to produce esters (By similarity). Expressed at very low levels in the cortex and skin of ripe fruit. Accumulates progressively at very low levels during fruit development, and fades out in ripe fruit. The fruit of cv. Royal Gala exhibits a high ester accumulation, whereas the cv. Granny Smith contains low ester levels; this influences strongly the ripe apple fruit aroma. Belongs to the plant acyltransferase family.