Starch iodine pattern as a maturity index for Granny Smith apples

Abstract Maturation of Granny Smith apples was followed in four Hawkes Bay orchards during March and April in 1976 and in one Auckland orchard from March to June in 1978 and 1979. During maturation the flesh firmness declined whereas the soluble solids content and starch pattern index increased, but the overall change in flesh firmness and soluble solids was small compared to that of the starch pattern index. Regression analyses indicated that the starch pattern provides the least variable mdex and thus could be a reliable parameter for predicting harvest dates and for assessing maturity at harvest.