| Abstract: | 北蟲草(Cordyceps militaris)是著名的食藥用菇，因人工培育相較於冬蟲夏草(Cordyceps sinensis)容易，故佔有一席之地。其中機能性成分包括腺苷、蟲草素及麥角固醇等；具有抗氧化、抗腫瘤和調節免疫等功能，故目前常經由固態發酵、萃取及純化等技術運用於藥品和保健食品之開發。豆科(Legume)則是近年固態發酵技術中利用的基質之一，豆類中的抗氧化物質包括生育酚、類胡蘿蔔素及酚類化合物等；已被證實具有降高血脂、減少血栓形成和抗癌等功能。固態發酵技術不僅成本低、所需設備較少，亦可於低水活性下進行發酵，可提供一個與菇類自然生長相近的環境，在適當的人工培育下，可獲得豐富的二次代謝產物。目前以豆類作為基質進行菇類固態發酵之研究相對較少；故本論文主要利用固態發酵之技術，使北蟲草利用不同豆類基質生長並進行篩選、機能性成分及呈味性質分析。本研究首先探討不同豆類(紅豆、綠豆、花豆、鷹嘴豆、黑豆和黃豆)之北蟲草固態發酵最適水分添加量，以此探討結果進行後續8 週培養並每週採樣，同時加入糙米基質作為對照，而後第一階段以產品中機能性成分的含量來篩選各基質最佳培養天數；第二階段以產品中抗氧化物質含量評估最佳之豆類基質。另瞭解發酵前後之一般成分，並以固態發酵較佳之北蟲草豆類產品進行呈味特性分析。固態發酵培養結果，豆類之最適水分添加量為50%，且菌絲體有深入基質之情況，以此結果進行後續北蟲草豆類固態發酵。培養完成之產品進行第一階段篩選，評估項目主要以發酵基質中最高蟲草素生成量來判斷不同北蟲草發酵基質之最佳培養天數，分別為42 天(糙米)、49 天(紅豆)、21 天(綠豆)、35 天(花豆)、14天 (鷹嘴豆)、21 天 (黑豆)、14 天 (黃豆)，而蟲草素含量最高者為北蟲草紅豆(5.99 mg/g)、綠豆(2.52 mg/g)為第二、糙米(1.90 mg/g)為第三。上述7 種北蟲草發酵物進行第二階段抗氧化物質含量之篩選，結果顯示發酵後之總生育酚含量，以北蟲草黑豆中含量最多(99.63 μg/g)、次之為黃豆(62.47 μg/g)、再者為紅豆(44.53 μg/g)；總類胡蘿蔔素與葉綠素含量部分，總類胡蘿蔔素含量最高之前三者為北蟲草黑豆(29.57 μg/g)、綠豆(9.82 μg/g)、鷹嘴豆(9.08 μg/g)，葉綠素含量以北蟲草黑豆(青仁)為多(10.21 μg/g)；總酚含量以北蟲草紅豆(226.94 mg/g)、綠豆(235.79 mg/g)、黑豆(230.34 mg/g)和黃豆(267.83 mg/g)之含量無顯著差異並列最多。將這些抗氧化物質含量經加總統計分析後，第二階段評估之結果，北蟲草紅豆、綠豆、黑豆和黃豆無顯著差異為最佳。綜兩階段篩選，得知北蟲草紅豆為7 種基質中最佳，次之為北蟲草綠豆。在一般成分方面，蛋白質含量部分，除北蟲草鷹嘴豆外其他於發酵後提升；脂肪含量部分，發酵後含量皆提高；碳水化合物部分，北蟲草花豆及鷹嘴豆含量增多、其他則減少；粗纖維含量部分，北蟲草糙米、黃豆及黑豆含量提高，其他為降低。在呈味性質方面，紅豆與綠豆經北蟲草固態發酵後其總可溶性糖醇、總游離胺基酸和總核苷酸含量增加，此結果表示呈味價值提升。綜上所述，7 種基質中最佳的北蟲草基質為紅豆、次之為綠豆，另紅豆與綠豆經北蟲草固態發酵後其呈味特增加。本研究結果可作為開發具保健功效北蟲草相關產品之應用參考。
Cordyceps militaris is a famous edible medicinal mushroom species that gainedtheir popularity in recent years to replaced the use of Cordyceps sinensis owing to its ease of cultivation property. The functional components of C. militaris including adenosine, cordycepin and ergosterol etc., which obtained through solid-state fermentation, extraction, purification and other technologies, showed great activities in anti-oxidation, anti-tumor and immune regulation and had currently been applied to medicinal and functional food industries. Legume is one of the substrates that used in the solid-state fermentation technology in recent years for the cultivation of C. militaris.It contains tocopherols, carotenoids phenolic compounds and has been confirmed to have activities in hypolipidemic regulation, thrombosis attenuation and anti-cancer. Solid-state fermentation is a cost effective method when it comes to mushroom cultivation. It can be operated in low water conditions that resembles to the natural growth condition of mushrooms, which under proper operation large amounts of secondary metabolites can be obtained. Unfortunately, there were relatively few studies regarding to the solid-state cultivation of mushrooms using legume as substrates. Therefore, the purpose of this study is to use legume as a substrate for C. militaris cultivation and to analyze the functional components and the taste characteristics of legume after the cultivation process.We first optimize the optimum water content for the growth of C. militaris in azuki bean, mung bean, speckled kidney bean, chickpea, black bean, and soy bean. Meanwhile, the amount of antioxidative compounds, biomass, adenosine, and cordycepin produced during 8 weeks of cultivation were also analyzed. Finally, the tasting characteristics of the fermented legume with the first two highest polyphenol were analyzed.Results showed that the optimum moisture content of the beans to promote the best growth of C. militaris was 50%, which showed deep penetration of the mycelium into the matrix. The cordycepin contents peaks at 42, 49, 21, 35, 14, 21, and 14 days of C. militaris cultivation in brown rice, azuki bean, mung bean, speckled kidney bean, chickpea, black bean, and soy bean respectively. The hightest cordycepin content was the C. militaris cultivated in azuki bean (5.99 mg/g), followed by mung bean (2.52 mg/g), and brown rice (1.90 mg/g). The total tocopherols content after fermentation were 99.63, 62.47, and 44.53 μg/g for the black bean matrix, soybean, and azuki bean respectively; the total carotenoids content after fermentation were 29.57, 9.82, and 9.08 μg/g for black beans, mung beans, and chickpeas respectively. Myceliums which werecultivated in black bean matrix produce highest amount of chlorophyll (10.21 μg/g) compared to other matrix. However, there were no significant difference in the total phenolic content among different cultivation matrix including azuki bean (226.94 mg/g), mung bean (235.79 mg/g), black beans (230.34 mg/g) and soybean (267.83 mg/g). Our results showed that the best matrix for the cultivation of C. militaris was azuki bean, followed by mung bean.For the results of general composition analysis. We found that there weresignificant increase of the protein content in all groups of matrix except chickpea. However, fat content increased in all fermentation groups; the carbohydrate contents decreased except speckled kidney bean and chickpea; the crude fiber content decreased in all groups except brown rice, black soybean, and soybean. For the results of taste characteristic analysis, the taste of C. militaris which cultivated in azuki bean and mung bean had improved owing to the significant increase of total soluble sugar alcohol, total free amino acids, and total 5’-nucleotide.In conclusion, the solid-state fermentation of azuki bean by C. militaris is the best among the other bean, followed by the mung bean. Furthermore, the C. militaris fermented azuki bean and mung bean improved their taste after fermentation. The results of this study can be used as a reference for the development of health-care products related to C. militaris. |
