金棗酒香氣品質之改善

Abstract

雖然坊間有部分業者嘗試以金棗為原料釀製成酒，然其香氣不若新鮮金棗甚至帶有異味（off-odor）。本研究將目前市售金棗酒香氣品質不佳問題重新界定為異味分子濃度過高，以及成品香氣接受度過低兩部分，以宜蘭產之長實金棗（Fortunella margarita Swingle），分別從發酵過程、香氣回添以及成品儲藏條件三個層面針對現存金棗酒香氣品質進行改善。發酵實驗結果顯示，相較於以原果汁在25°C下發酵者、分離果汁皮油並在16°C下發酵者、和原果汁在16°C下發酵者，分離果汁皮油並在25°C下發酵者較快達到發酵終點。此外，以氣相層析儀分析在25°C下發酵後成品，發現無論發酵前是否分離皮油，成品香氣成分與其相對濃度並無太大差異。消費者品評結果顯示，於25°C下發酵的兩個處理組經香氣回添後有較高的香氣接受度。在香氣成分方面，分離果汁皮油並在25°C下發酵者在回添皮油後有較高的金棗指標香氣化合物citronellyl acetate。儲藏實驗中，由limonene以及α-terpinol儲藏八週後的相對含量變化可知，添加150ppm二氧化硫對於防止香氣降解與劣變的效果不若降低儲藏溫度來的有效。然而，由儲藏後品評結果可知，以本研究所述條件所得之產品無論添加二氧化硫與否、儲藏於25°C或4°C下，經八週後之香氣變化仍不為一般民眾所察覺。

Although there has been a small amount of wine made by kumquat in Taiwan, the aroma of these kumquat wines does not receive positive respond from the consumer. In this study, the problem was further defined as the higher concentration of the off-odor compound and the lack of aroma acceptability in wine. The kumquat (Fortunella margarita Swingle) produced in I-lan was used as the material in this study. The processes charged for aroma improvement involved fermentation, aroma recovery, and storage condition of the final product. Firstly, the results from fermentation experiment indicate that the juice, which fermented at 25°C after removing peel oil, had the process completed most rapidly than the juice containing peel oil fermented at 25°C, the juice fermented at 16°C after removing peel oil and the juice containing peel oil fermented at 16°C. In addition, the aroma and its relative concentration had little difference between the wine which peel oil was removed or not before fermenting at 25°C. Secondly, the results from consumer''s sensory evaluation show that both the treatment fermented at 25°C received higher aroma acceptability after aroma recovery. In aroma components, the wine fermented at 25°C after removing peel oil has higher concentration of citronellyl acetate, the characteristic odor compound in kumquat. Thirdly, the changes of limonene and α-terpinol contents during 8-week storage indicate that SO2 had an insignificant effect on preventing aroma degradation; instead, to use low temperature for preventing aroma degradation was more effective. However, according to the outcome of consumer’s sensory evaluation, there was neither significant difference between the wines stored at 25°C and 4°C, nor between those added with SO2 or not.