| 摘要： 台灣產之中山月拔成熟後香氣甚佳，爲果汁加工之主要原料。本研究以Hunter's之L、a、b值測量中山月拔果實後熟過程之色澤變化，及利用固相微萃取法(solid-phase microextraction, SPME)結合氣相層析儀(gas chromatography)及氣相層析質譜儀(gas chromatograph-mass spectrometer, GC-MS)進行揮發性成分分析與鑑定。結果顯示，未後熟果其Hunter's之L值與b值隨後熟時間的增加而提高；熟果與過熟果其Hunter's之L值與b值有先上升後下降趨勢；Hunter's之a值部份，未後熟果與過熟果隨不同後熟時間的增加，呈現先上升後下降再上升的趨勢。未後熟果之主要揮發性酯類成分爲(Z)-3-hexenyl acetate，熟果與過熟果主要酯類成分則爲(Z)-3-hexenyl acetate、hexyl acetate及ethyl hexanoate，而cinnamyl acteate只在過熟果中檢測出。成熟時以(Z)-3-hexenyl acetate最先生成，methyl butanoate及ethyl acetate在後熟晚期生成。本研究也對中山月拔（未後熟果、熟果及過熟果）全果及切塊之揮發性成分加以比較分析，並因而推測未後熟果之 1,8-cineole、monoterpenes及sesquiterpenes是其所含青香之貢獻成分。'Chung-Shan-Yueh-Pa' is a guava (Psidium guajava L.) cultivar used for juice processing in Taiwan because of its aroma. In this research, we examined the composition changes in color and volatile compounds of 'Chung-Shan-Yueh-Pa' guava fruit during ripening. The volatile compounds were isolated from guava fruits by solidphase microextraction (SPME) then identified qualitatively and quantitatively by GC and GCMS analysis. Changes of Hunter's L, a, b values of the fruits were studied and found L and b values of the unripe fruit's were increased during maturation. The ripe and overripe fruits' L and b values were increased first and then decreased during ripening. The major volatile compound identified in the unripe fruit was (Z)-3-hexenyl acetate. On the other hand, the main volatile compounds identified in the ripe and overripe fruits were (Z)-3-hexenyl acetate, hexyl acetate and ethyl hexanoate. Regarding changes of esters in fruits during ripening, (Z)-3-hexenyl acetate was produced first, then methyl butanoate and ethyl acetate increased in later periods. Volatile compounds of Chung-Shan-Yen-Pa guavas (unripe fruit, ripe fruit and overripe fruit) between different types of whole fruits and cubes were also compared and it was postulated that 1,8-cineole, monoterpene and sesquiterpene contribute the green note of unripe guava. |
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