Flesh properties of the edible and peel portions of watermelon (Citrullus lanatus, (THUMB.) MATSUM.) were studied in connection with the pectic substances during maturation from considerable unripe to overripe stages. The effects of pectins, hemicellulose and cellulose components on the watermelon tissues were also investigated on the four kinds of rootstocks; white-flowered gourd (Logenaria siceraria (MOE.) STANDL.) ; squash (Cucubita moschata, POIR.) ; wax gaurd (Benincasa hispida, COGN.) ; one seeded bur cucumber (Sicyos angulatus, L.). Total amount of solube pectins in edible portions was about 20-40mg% in the raw flesh during maturation, which consist of about 75-85% of hydrochloric acid-soluble pectin and 11-14% of water-soluble pectin. It was found that the soluble pectins among the four kinds of rootstocks. In the peel portions, the total amount of soluble pectins was about 150-250mg% in the fresh material, which consist of about 35-40% of water-soluble pectin and about 50-55% of hydrochloric acid-soluble pectin. The total amount of hemicellulose A and B was 47-61 mg% in the edible portions and 65-142 mg% in the peel portions for the four kinds of rootstocks. Similary, the amount of α-cellulose was 63-126 mg% in the edible portions and 339-544 mg% in the peel portions in the fresh materials, respectively. From these results, it appears that the effect of their components on the flesh qualities of edible portions was greater in α-cellulose than in both pectic substance and hemicellulose.

スイカ果実の成熟中の肉質の状態および台木の種類の異なる果実の肉質の状態とペクチン質, ヘミセルロースおよびセルロースとの関連性について, 主として日章レッドを中心に調べた. 果肉部の全ペクチンは新鮮果重当たり約20?40mg%であり, そのうち, 塩酸可溶性ペクチンの占める割合は75?85%, 水可溶性ペクチンは約10?20%であった. この可溶性ペクチン含量と組成比は熟度や台木の種類による差異はあまり認められなかった. 果皮部(表皮を除く)では熟度がすすむにつれて可溶性ペクチンはいずれも増加した. 全ペクチンは新鮮果重当たり約150?250mg%であり, そのうち, 水可溶性ペクチンの占める割合は約35?40%, 塩酸可溶性ペクチンは約50?55%であった. ヘミセルロースAおよびBの合計値は新鮮果重当たり47?61mg%であり, 使用した4種類の台木の間であまり差異は認められなかった. しかし, α-セルロースはユウガオやアレチウリの台木では63mg%と65mg%であまり変わらないが, カボチャ台木ではその約1.5倍, トウガンでは約2倍の高い値であった. 果肉の性状に及ぼす影響はペクチン質やヘミセルロースは比較的少なく, それに比べてα-セルロースの影響が大きいと思われる. しかし, 肉質の緻密性や歯切れとの関係については明らかではない.