VARIATIONS OF ACIDITY IN THE PEEL OF ACID CITRUS .2. ORGANIC-ACIDS DETECTED IN THE FLAVEDO AND ALBEDO OF ACID CITRUS BY HPLC

To elucidate organic acid(s) responsible for differences in acid accum ulation in the flavedo of Kabosu (C. sphaerocarpa Hort. ex Tanaka), Yu zu (Citrus junos Sieb. ex Tanaka), Lisbon' lemon (C. limen Burm. f. Li sbon), Hanayu (C. hanayu Hort. ex Shirai), and Sudachi (C. sudachi Hor t. ex Shirai), seasonal changes in organic acid composition of their f lavedo and albedo were investigated by a high performance liquid chrom atography (HPLC). While malate was a predominating acid only in the fi rst sampling date (Sep. 16) in the flavedo and albedo of Japanese acid citrus and the albedo of Lisbon as it dropped quickly, malonate incre ased tremendously in the later sampling dates. Oxalate was present in the flavedo and albedo of all citrus investigated, and mostly decrease d slightly. In the flavedo of Lisbon, malate and malonate were relativ ely stable, citrate was barely detected. Citrate increased and was fou nd to be a major acid only in the flavedo of Kabosu and Yuzu.