乾燥方法對臺灣山胡椒總酚含量、抗氧化力及氣味組成的影響

Effects of Drying Methods on Total Phenolic Content, Antioxidant Activity and Volatile Composition of Litsea cubeba (Lour.) Pers. in Taiwan

譚國鋈(Kwok-Yuk Tam) ； 林書妍(Shu-Yen Lin)

《臺灣園藝》 66卷4期 (2020/12) Pp. 181-194

摘要

原民香料「馬告」為山胡椒（Litsea cubeba（Lour.）Pers.）樹之果實，通常在採收果實後日曬乾燥以保存。由於日曬操作需要經驗、不穩定性高，且未有相關研究說明乾燥對果實成分的影響，因此本研究將探討不同乾燥方法的乾燥效率。試驗材料為花蓮縣瑞穗鄉的新鮮山胡椒果實，果實分三批次分別進行40℃、60℃、80℃烘乾及-50℃冷凍乾燥，另以日曬乾燥為對照組，乾燥過程記錄水分含量變化，至恆重為乾燥結束。乾燥果實經磨粉及甲醇萃取後，以Folin-Ciocalteu法分析總酚含量、以DPPH（1,1-diphenyl-2-picrylhydrazyl）、ABTS（2,2'-azino-bis（3-ethylbenzthiazoline-6-sulphonicacid）法分析抗氧化能力，並以SPME-GC-MS分析氣味組成。分析結果顯示，冷凍乾燥的果實具有最高的總酚含量（17.95mg．g^(-1)）、DPPH及ABTS自由基清除能力；80℃熱風烘乾有最好的乾燥效率（9小時達恆重），果實的總酚含量、自由基清除能力皆高於其他熱風乾燥處理。乾燥方式明顯影響氣味特徵，冷凍乾燥及80℃熱風烘乾的果實中，有較高比例的檸檬醛及β-石竹烯，此二者貢獻了山胡椒果實的檸檬香及胡椒香。40℃烘乾與冷凍乾燥果實氣味則有較多的單萜類。以感官品評嗅聞，60℃烘乾組與日曬乾燥組有較明顯的薑氣味。總和分析結果及感官品評評估，冷凍乾燥為最能有效保留高機能性成分、多氣味組成成分的乾燥方式，若考慮乾燥效率及成本，則以60至80℃熱風乾燥為維持山胡椒果實品質較佳的乾燥條件。

關鍵字

馬告 ； 香料作物 ； 原民文化 ； 初級加工

並列摘要

Litsea cubeba (Lour.) Pers., also called 'Maqaw', is a traditional spice used by the Taiwan indigenous race Tayal. The fresh fruit of L. cubea is sun-dried after harvest for long-term storage. The operation of sun-drying depends highly on weather and it is hard to manage well, so that makes the quality of 'Maqaw' products inconsistent. Since there is no relevant research showing the effect of drying on the composition of the fruit, this study explores the drying efficiency and the effects on the fruit quality. Fresh fruits of L. cubeba from Hualien county were conducted by 5 drying methods respectively, which were 40℃ , 60℃, 80℃ oven-drying, -50℃ free-drying, and sun-drying. The moisture content was recorded during the drying process until the weight was constant, which was also defined as the end of drying. After the dried fruits were grounded and extracted by methanol, the total phenol content (TPC) was analyzed by Folin-Ciocalteu method, the antioxidant capacity was analyzed by DPPH (1,1 -diphenyl-2-picrylhydrazyl) and ABTS (2,2'- azino-bis(3-ethylbenz thiazoline-6-sulphonic acid), and the volatile composition was analyzed by SPME - GC-MS. The results showed that the fruits processed by freeze -drying had the most TPC (17.95 mg．g^(-1)), which was the highest DPPH and ABTS performance. The 80℃ oven drying was the most effective drying method, as it took only 9 hours to make the fruits reaching the weight constant. Fruits of 80ºC oven drying treatment had a higher TPC and antioxidant capacity than other oven drying methods. Drying methods affected the aroma characters of fruits. As the fruits from freeze -drying and 80ºC oven-drying treatments had higher composition ratio of limonene and β-caryophyllene, and these two compounds contributes most to the lemon and pepper scent of L. cubeba. More monoterpene volatile compounds were detected in fruits of freeze-drying and 40℃ oven drying. By sensory evaluation, the obvious ginger scent could be detected from fruits of 60℃ oven drying and sun-drying treatments. Judging from both results, fruits using freeze - drying retain the most functional compositions and the aroma characteristic compositions. Considering the drying efficiency and cost, 60℃ and 80℃ oven -drying are the recommended drying method for fruits of L. cubeba.

並列關鍵字

maqaw ； spice crop ； indigenous culture ； primary processing