| Abstract: | 食用菇菌含有許多生理活性物質，這些生理活性物質同時也是此類食物美味的來源之一。主要是因食用菇菌擁有大量的鮮味成分，當中包括多種核苷酸及游離胺基酸，其中的核苷酸類5´-GMP、5´-IMP、5´-XMP 和5´-AMP 等，以及胺基酸類的L-glutamic acid 和L-aspartic acid，這兩類物質同時存在時，會產生加乘作用而提供出更濃郁的鮮味。以往的鮮味劑多數是利用化學合成或運用強酸分解而得到，由於化學合成或酸水解會有殘留及污染環境等疑慮，較不具健康天然的訴求，而且由水產品水解生產，將無法提供素食者食用。
菇類基底大多為肥料或廢棄物，而基底佔菇類總重量越10~20%，若能有效利用將會是一大利益，在眾多基底中，僅杏鮑菇基底受消費者所接受為食材，因此本研究採用杏鮑菇的基底。杏鮑菇（Pleurotus eryngii）為側耳屬的一種菇類，作為台灣早期發展的菇類之一，在2013年之產量已達22,000 公噸，產值約為17 億元，在台灣菇類中產值排行第三。
杏鮑菇內含豐富的鮮味物質和機能性成分，只要運用生物轉化技術，就可得到更多鮮味物質及機能性成分。本研究將以多種方式水解杏鮑菇的基底，產生鮮味加乘的胺基酸和核苷酸，過程中將探討轉化出鮮味成分的適化條件，開發具機能性之鮮味調味劑。結果顯示杏鮑菇基底水解後的溶解度，分別以均質90秒( 55.37% )、超音波震盪15分鐘( 51.28% )、熱水萃取150分鐘( 53.53% )、反覆凍融4次( 56.95% )、 蛋白酶 (pH6, Aspergillus oryzae) (65.30%) 及 (pH7 Bacillus amyloliquefaciens) (63.75% )水解1小時之水解物溶解度最佳；核苷酸含量則以熱水萃取150分鐘效果最好 (12.62 mg/g)，而胺基酸含量則以兩種酵素混合法之含量最高 (62.73及61.25 mg/g)。
考量到時間及效率，故最終水解條件為均質90秒、反覆凍融2次，加入蒸餾水並超音波震盪15分鐘後，再加入兩種酵素以40℃分解60分鐘做第一道萃取，離心後沉澱物再以80℃ 熱水萃取150分鐘作為最終水解條件。
水解後將萃取液以麥芽糊精作為賦形劑，進行冷凍乾燥並磨粉製成成品，其中加入0及2.5 g 的麥芽糊精的成品粉末容易吸濕結塊不易保存，不適合作為產品，故在此之外以鮮味值最高，以添加5 g 麥芽糊精之粉末最好。
Edible mushrooms contain many physiologically active substances, and also delicious food sources. Because of edible mushrooms contain higher amounts of umami components, including umami 5'-nucleotides (5'-GMP, 5'-IMP, 5'-XMP and 5'-AMP) and MSG-like amino acid (L-glutamic acid and L-aspartic acid), etc. It can be created the synergistic effect to provide the efficient flavor enhancers and positive flavor modulators, when the MSG-like amino acids and the umami 5'-nucleotides were existed at the same time. In the past, the MSG was obtained by chemical synthesis or hydrolysis, which caused the chemical residues and environmental pollution that cannot provide the demand of health and natural. Additional, the product of from aquatic by hydrolysis, which are unable to provide for vegetarians.
Most of the mushroom base is use as fertilizer or waste, and it is 10-20% of the total weight of the mushroom. If it can be effectively utilized, it will be a big benefit. Among many type of mushroom base, only the base of Pleurotus eryngii is accepted by consumers as ingredients of food. So this study used the base of Pleurotus eryngii as material. Pleurotus eryngii is a kind of mushroom of Pleurotus. As one of the earliest developed mushrooms in Taiwan, its output in 2013 has reached 22,000 tons, with an output value of about 1.7 billion. The output value of mushrooms is ranked third in Taiwan.
Pleurotus eryngii contained lot of umami substances and functional components, which could be transformed into the flavor substances and functional ingredients by biotransformation technology. Meanwhile, we will conduct various hydrolysis method to acquire the umami ingredients of flavor and functional components from the base of mushrooms.
The results showed that the solubility of Pleurotus eryngii after homogeneous 90 seconds (55.37%), ultrasonic shock (51.28%), hot water extraction for 150 minutes (53.53%), repeated freezing and thawing 4 times (56.95%), hydrolysis with pH7 protease from Aspergillus oryzae (65.30%) and pH7 Protease from Bacillus amyloliquefaciens (63.75%) for 1 hour with the best solubility. The content of nucleotides was the highest after extracted with 80℃ hot water for 150 min (12.62 mg/g). While the content of amino acids was the highest with hydrolysis with each kind of enzyme (62.73, 61.25 mg/g).
Taking into account the time and efficiency, the final hydrolysis conditions is homogenization of 90 seconds, repeated freezing and melting 2 times, adding water then ultrasonic shock for 9 minutes, then adding two enzymes hydrolysis at 40℃ 1 hour as first extraction. After centrifugation, the precipitate was extracted with hot water at 80 ° C for 150 minutes for final hydrolysis. After the hydrolysis, the extract is freeze-dried with maltodextrin as an excipient and then ground into a product. The powder added with 0, 2.5 g maltodextrin is easily hygroscopic and agglomerate. It’s not easy to preserve and is not suitable as a product. It is best to add 5 g of maltodextrin powder with the highest umami taste. |
