Effect of Fruit Size on the Quality of White-fleshed Peach Cultivars

doi:10.3969/j.issn.1009-9980.2003.06.004

Abstract：The skin color and juice chemical composition in large (L), medium (M), and small (S) fruit of four peach cultivars, Hashiba-hakuho (early season cultivar), Hakuho (early-medium season), Shimizu-hakuto (medium season), and Hakurei (late season) were observed and analyzed. The fruit containing soluble solids higher than 12 Brix were sampled at a commercial packinghouse located in the southern part of Okayama prefecture of Japan, then were stored at 25℃ until fully ripened. The skin color on the cheek (yellowish) was dark in S fruit of Hashiba-hakuho and the color at the fruit top (reddish) was dull and dark yellowish in L fruit of Shimizu-hakuto and Hakurei, compared to the fruit of other sized. The sucrose and fructose contents in juice, the major source of the sweetness, were higher in S and M fruit in Hakuho, Shimizu-hakuto, and Hakurei,while the malic and citric acid contents, the major sour constituents, were lower in L fruit in those cultivars. Asparagine, the biggest amino acid fraction and thought to deteriorate the fruit taste at high levels, was higher in L fruit than in S fruit in Hashiba-hakuho and Hakuho. The content in Shimizu-hakuto and Hakurei fruit was generally low and not affected by fruit size. The content of γ-decalactone, a major peachy aromatic substance, was higher in L fruit of Hashiba-hakuho, in M fruit of Hakuho and Shimizu-hakuto, and in S fruit in Hakurei, than those of other sized. Sensory tests revealed that flavor of the L fruit in Hakuho and S fruit in Hakurei were poor. These results indicated that the larger fruit of Hakuho, Shimizuhakuto, and Hakurei, the representative white-fleshed peach cultivars grown in Okayama of Japan, have rather flat tastes than the medium sized fruit because of their lower sweetness and sourness and weaker aroma, as well as a poorer texture.