紅龍果果實生長期間果實和肉質莖組成分之變化

Compositional Changes in the Fruit and Cladode of Hylocereus undatus During Fruit Growth and Maturation

本研究分析紅龍果果實生長期間各階段，果肉、果皮和肉質莖之成分變化。結果果肉在轉色期間全可溶性固形物及全可溶性糖隨果實生長迅速增加，澱粉則迅速減少，直至果實完全成熟。果皮全可溶性糖含量在果實生長期間維持穩定，但澱粉含量則在生長後期下降。果肉可溶性糖主要為葡萄糖和果糖，另有少量蔗糖。肉質莖各成分含量在果實生長期間維持穩定。蘋果酸是果皮中主要的有機酸，在果實生長期間緩慢的增加。果肉可滴定酸在果實轉色前出現短暫的高峰。果肉有機酸以蘋果酸最多，其含量變化與可滴定酸變化相似。有機酸增加後，果皮隨即進入轉色階段。果肉中的有機酸除蘋果酸外還有少量的檸檬酸、抗壞血酸和草酸。 Compositional changes in the pulp, peel and cladode of Hylocereus undatus during fruit growth and maturation were studied. After the onset of peel color change, from green to red, the concentration of total soluble solids and total soluble sugars in the pulp increased rapidly, while starch decreased. The changes continued until the fruit was fully ripe. Total soluble sugars content in the peel remained stable throughout fruit growth. Starch concentration declined at the later stage of fruit growth, however. Sugars in the pulp were mainly glucose and fructose, and a small amount of sucrose. Soluble sugars in the cladode remained constant throughout fruit growth. Malic acid as the predominant organic acid in the peel gradually increased during fruit growth. Titratable acidity in the pulp showed a peak surge at the beginning of color change. Malic acid, the main organic acid in the pulp, changed in a similar pattern as titratable acidity. Other minor organic acids found in the pulp were citric acid, ascorbic acid and oxalic acid.