|關鍵字： ‘牛心柿’；真空脫澀；褐化；澀柿；甜柿；‘Bull Heart’ persimmon；vacuum deastringency；browning；astrigent persimmon；non-astrigent persimmon
|摘要： 本試驗以17個品種之柿葉為材料，期能尋求果實是否具澀味相關指標，比較澀柿與甜柿葉片礦物元素濃度差異，鐵元素為甜柿高於澀柿；錳元素為澀柿高於甜柿，其他元素則沒有顯著性差異。柿品種間的差異性大，澀柿品種有的可溶性單寧濃度高，有些濃度偏低；甜柿也有相同的情形。因此無法以葉片單一個指標，作為判斷果實是澀柿或甜柿。‘富有’與‘蜂屋’柿果生長期間可溶性單寧濃度變化，澀柿之可溶性單寧濃度高於甜柿，隨著生長期間增加可溶性單寧濃度逐漸下降。‘蜂屋’果實總酚類化合物濃度、銅元素與氮元素濃度在生長期間皆高於‘富有’柿果。鋅元素與鈣元素則是‘富有’高於‘蜂屋’。果實生長後期之鐵元素濃度‘富有’高於‘蜂屋’；錳元素濃度則為‘蜂屋’高於‘富有’。可溶性單寧濃度與銅元素之間可能相互影響，曾有研究指出單寧會吸附銅離子，因此澀柿的銅元素高，可能受到單寧細胞之影響。 ‘牛心柿’真空脫澀後，果皮會出現褐化的情形，因此分析不同園區之無機營養元素濃度，2016觀察到B園區的錳元素濃度偏低，且褐化指數低，但是2017年試驗卻發現錳元素可能非影響褐化之原因。真空處理之脫澀時間與溫度，影響果實脫澀程度，真空24小時，柿果無法脫澀，至少需要真空處理48小時才可以脫澀。脫澀溫度為20℃或40℃下柿果無法脫澀，脫澀最佳溫度為30℃或33℃。延遲時間脫澀與熱處理可以降低果實褐化之發生，但是延遲時間脫澀會造成果實硬度下降；而溫湯處理50℃15分鐘與30分鐘，熱風處理50℃3小時，果實會受到熱傷害。真空脫澀與乙烯抑制劑1-MCP複合處理，可以維持柿果之硬度，減緩果實硬度下降，使風味與口感較佳，延長柿果之貯藏時間。果實脫澀後丙二醛之濃度會上升，有膜脂過氧化的現象，進而導致柿果褐化。溫湯處理50℃15與30分鐘，可降低丙二醛之濃度，褐化指數也較低。苯丙胺酸裂解酶活性與褐化指數呈負相關，當苯丙胺酸裂解酶活性高時，褐化指數較低。褐化指數會受到溫度之影響，在38℃脫澀後果實貯藏在25℃，褐化指數最高，但是多酚氧化酶、總酚類化合物、丙二醛濃度卻較其他處理組低。真空脫澀與乙烯抑制劑1-MCP共同處理，使柿果脫澀後，維持果實之硬度與可溶性固形物。果實脫澀處於低氧環境，使柿果容易受到損傷，放置在空氣中時間越長，果皮之褐化情形即越嚴重，因此透過1-MCP處理可以延緩果實軟化，延遲時間脫澀也可以降低果皮之褐化指數，柿果可以維持較佳之品質。The experiment used 17 cultivars of persimmon leaves as materials. Expect to find out whether the fruit has astringency related indicators. Comparison between the mineral elements concentration of astrigent persimmon to non-astrigent persimmon leaves. Non-astrigent persimmon has higher the iron element than the astrigent persimmon, but no significant difference in other elements. Persimmon cultivars vary widely, but different properties are observed even with the same variety, for example, some astringent persimmon cultivars have high concentrations of soluble tannins while others have low concentrations; the same observation can be made on non-astrigent persimmon as well. Therefore, it is impossible to directly determine base on the leaves whether the plant was astringent or non-astringent persimmon with a single trait. Change of soluble tannin content during persimmon fruit growth in ‘Fuyu’ and ‘Hachiyagaki’, the soluble tannin concentration of astringent persimmon is higher than that of non-astringent persimmon. The concentration of soluble tannins gradually decreased as the growth of fruits. The content of total phenolic compounds, copper, and nitrogen in the ‘Hachiyagaki’ are higher than ‘Fuyu’ persimmon fruits during growth. The element of zinc and calcium in ‘Fuyu’ is higher than ‘Hachiyagaki’. The element of iron in the late fruit stage was higher in ‘Fuyu’ than that of ‘Hachiyagaki’; the element of manganese in ‘Hachiyagaki’ was higher than ‘Fuyu’. The soluble tannin concentration may interact with the element of copper. It has been reported that tannins adsorb copper ions, therefore the astringent persimmon was high in copper ions and may be affected by tannins. After the vacuum deastringency treatment of ‘Bull Heart’ persimmon, the peel will appear brown, so the concentration of essential plant nutrients in different orchards was analyzed. The content of manganese in B orchards was observed to be low, which may be related to the browning index of persimmon fruits in 2016. However, repeated test in 2017 found that manganese content and browning of peel may not be directly correlated. Vacuum treatment of time and temperature will affect, the degree of fruit deastringency. When vacuumed for 24 hours, persimmon fruit would not be deastringent. However, with at least 48 hours of vacuum time, the persimmon fruits will become deastringent. If the deastringent temperature was 20°C or 40°C, deastringent will not occur, and the optimal temperature was 30°C or 33°C. Delaying time deastringent and heat treatment could reduce the occurrence of fruit browning, but delayed deastringent time would cause the softening of the fruit. However, when the hot water was treated at 50°C for 15 and 30 minutes or the hot air was treated at 50°C for 3 hours, the fruit would be damaged by heat injury. Vacuum treatment and ethylene inhibitor 1-MCP complex treatment could maintain the firmness of persimmon fruits if slow down the decrease firmness of fruit would have better the flavor and taste and persimmon fruits to be stored longer. The content of malondialdehyde increased after the fruit was deastringent, and malondialdehyde caused membrane lipid peroxidation induced browning of persimmon fruits. Hot water treatment by 50°C for 15 and 30 minutes was able to reduce browning index and the content of malondialdehyde. The phenylalanine lyase activity was negatively correlated with the browning index. When the phenylalanine lyase activity was high, the browning index was lower. The browning index was affected by temperature, as the fruit was stored at 25°C after being vacuum deastringent at 38°C caused the browning index of fruits to be the highest, but the content of polyphenol oxidase, total phenolic compounds, and malondialdehyde was lower than that of other treatments. Vacuum deastringency and ethylene inhibitor 1-MCP composite treatment can be combined to maintain firmness and soluble solids of the persimmon fruits. The persimmon fruits were in a low oxygen environment, which made them prone to bruising. When they were placed in ambient temperature for longer period of time, the more severe the browning of the persimmon peel, so that the treatment of 1-MCP could delay the softening of the fruits. Delay time treatment could reduce the browning index of persimmon fruits can maintain better quality.