不同套袋處理對‘Ruby’葡萄柚果實顏色與主要果皮色素組成之影響

nfluences of Fruit Bagged Treatments on Fruit Color and Major Peel Pigment Constituents of Grapefruit (Citrus paradisi Macf. ‘Ruby’)

本試驗主要探討不同時期套袋與紙袋顏色對‘Ruby’葡萄柚（Citrus paradise Macf.）果實顏色與主要果皮色素組成之影響，包括早期套黑色袋與白色袋、晚期套黑色袋與不套袋等處理。果皮顏色參數變化，各處理之L*及C*值均隨果實發育而增加，h°則隨發育而減少，且套黑色袋者顏色轉變較快，果皮脫綠明顯，於最後採收時（11月27日）果皮呈紅橙色，而不套袋處理者至採收時果皮仍維持綠色。各處理果肉之L*及C*值均隨果實發育而減少，h°則是稍減少而後增加。最後採收時各處理果肉之L*及C*值均無明顯差異，而h°則以晚期套黑色袋處理者較低，明顯較不套袋者偏紅。色素分析顯示，不論何種處理，果皮葉綠素含量均隨果實發育而減少，以套黑色袋者含量最低，葉綠素a含量減少較快，而不套袋與套白色袋者則以葉綠素b之含量減少較快。套黑袋者果皮類胡蘿蔔素於發育過程中先減少而後增加，其組成以Lycopene為主，僅不套袋者於最後採收時仍有少量α-carotene存在。相關分析顯示，‘Ruby’葡萄柚果皮葉綠素含量與L*值呈負相關，與h°呈正相關；類胡蘿蔔素及Lycopene含量則與h°呈負相關，且Lycopene有較高之相關性（r2＝0.6941**）。 Color is an important fruit characteristic in grapefruit (Citrus paradise Macf.). The experiments investigated the influences of bagging periods and paper color on fruit color and major peel pigment constituents of ‘Ruby’ grapefruit at various stages. The treatments of fruit bagged were bagged with black paper in late May and late June and with white paper in late May, respectively. Control fruit were not bagged. The peel color parameters both L* and C* values increased, but h° value decreased after bagging. Peels of fruits bagged with black paper notably degreened and turned to reddish orange at harvest on 27 November, and that of control was still yellow green. The L* and C* values of flesh decreased after bagging in all of the treatments. The h° value of fruit flesh decreased and then increased with fruit development. There was insignificantly different among treatments in L* and C* values of flesh at each sampling date, but the flesh of fruits bagged in late May with black paper had lower h° and deeper red than those of control at harvest. In all treatments total chlorophyll content in peels decreased with fruit development and fruits bagged with black paper had lower content than the others. Chlorophyll a content in peel of fruits bagged with black paper decreased much rapidly, but chlorophyll b content was lower in those bagged with white paper or control. There was a significant negative correlation between chlorophyll content and L* value and positive correlation with hue angle (h°). Lycopene was main carotenoids of peel, the content decreased slightly at all stage and then increased in the peel of fruits bagged with black paper at harvest. There was a significant correlation between hue angle (h°) and lycopene content (r2 =0.6941**). Small amount of α-carotene (0.51µg/g FW) was found in the peel of control fruits at harvest stage, but it was not detected in those of others.