hanges in Contents of Sugars, Starch, Organic Acids and Free Amino Acids in Kiwi Fruit during Growth and after Ripening

Studies on Constituent in Kiwi Fruit Cultured in Japan Part I

Abstract

Content of sugars, starch, organic acids and free amino acids in kiwi fruits (Actinidia chinensis PLANCH. cv. Hayward and cv. Bruno) were determined in growing during June to November and after ripening at 15°C. The following results were obtained. (1) Total sugar content in Hayward and Bruno were low, approximately 0.5% in both cultivars until four months from pollination and gradually increased with fruit enlargement. Total sugar content of Hayward and Bruno harvested at final sampling day was 1.8% and 5.2%, respectively, and those after ripening was 6.4% and 6.3%, respectively. (2) Amounts of glucose and fructose in after-ripened fruit were almost the same, about 3.0%, and occupied 90% of total sugar. (3) Hayward and Bruno fruit obtained at ten days before final sampling day contained 6.5% and 6.0% starch, respectively. At final sampling day starch decreased 4.5% in Hayward and 2.3% in Bruno and 0.3% in both cultivars after ripening. (4) Quinic, citric and malic acids were estimated as major organic acids in growing and after-ripened fruit. Although changes of quinic and malic acids content during growth were slight, considerable increase was shown in citric acid content. Content ratio of quinic, citric and malic acids in after-ripened fruit was nearly 1:1:0.2. (5) Total amounts of free amino acids in fruit showed a little change during growth and after ripening. Free amino acids contained in after-ripened fruit at comparatively higher amounts were arginine, alanine, γ-amino butyric acid, glutamic acid and threonine.