酸、甜楊桃葉片與果實草酸含量之比較

Comparison of Oxalic acid Content in Leaves and Fruits among Tart and Sweet Lines of Carambola (Averrhoa carambola L.)

楊桃為草酸含量較高的水果，近年來報導對人體健康會成負面的影響，育成高品質且低草酸品種為當前最主要的研究工作，以降低消費者疑慮。分析酸楊桃及甜楊桃品系葉片中草酸含量的差異，以及草酸生合成的關鍵酵素─乙醇酸氧化酶之活性，與楊桃中草酸含量高低之相關性，可作為楊桃育種早期篩選的指標之一。研究發現，在甜楊桃果實中草酸含量隨著成熟度增加而有下降的趨勢，在酸楊桃亦有類似的結果，但酸楊桃果實不論成熟度，其草酸含量皆顯著高於甜楊桃果實；酸楊桃之乙醇酸氧化酶活性在葉片及果實中，皆高於甜楊桃品種。 Recent media reports have warned that carambola with high oxalic acid content has high health risk, therefore, in order to minimize consumer worries, producing high quality and low oxalic acid carambola has become primary work. The oxalic acid content and glycolate oxidase activity were analyzed among the tart and sweet carambola, and they were indicators for breeding screens. Results indicated that the oxalic acid tended to decrease during maturation in both types of carambola. However, regardless of maturity, the oxalic acid content in tart carambola was always higher than that in sweet carambola. Glycolate oxidase activity in leaves and fruits of tart carambola was also higher than that in sweet carambola.