不同生長條件對台灣藜幼苗機能性成分之影響

Abstract

台灣藜 (Chenopodium formosanum Koidz.)，傳統稱為紅藜、赤藜，為台灣原生作物，除了當作台灣原住民釀小米酒的酒麴原料以外，本身亦具有豐富的營養價值，高量的膳食纖維及蛋白質，多種人體必需胺基酸如離胺酸、纈胺酸等，以及微量元素鋅、硒及鍺等。機能性成分方面，種子的抗氧化能力十分優秀，其主要來源是甜菜色素及酚類化合物，對於預防人類慢性疾病發生極具潛力，甜菜色素同時也是其果穗色彩豔麗的主因。台灣藜種子含有高量的γ-胺基丁酸 (γ-Aminobutyric Acid, GABA)，為一種游離胺基酸，在人類中樞神經系統內是十分重要的抑制性神經傳遞物質，具鎮定、助眠、預防憂鬱及其他如高血壓、糖尿病等疾病的發生。基於以上種種優良效用，台灣藜近年逐漸受到矚目，惟大多數人幾乎只食用種子的部分，有多項研究指出，種子發芽後其機能性成分及抗氧化能力會大幅增加，特別是GABA含量；逆境也是誘導GABA含量增加的因子之一。本研究依序從溫度 (18 ℃、24 ℃及30 ℃)、種植天數 (1~7天) 及鹽份逆境處理 (50、100、150及200 mM) 三個試驗，探討不同環境因子對於台灣藜幼苗機能性成分及抗氧化能力之影響。結果顯示台灣藜幼苗在高溫下，次級代謝物含量最高；低溫時其抗氧化潛力最大，且發現台灣藜幼苗保健功效與總酚含量為正相關。在種植5-6天時，具有最高的次級代謝物含量及抗氧化能力，且所有機能性成分皆與抗氧化能力相關。鹽分逆境試驗結果顯示適度的鹽分濃度可有效增加作物生理表現、機能性成分含量及抗氧化能力，在鹽分逆境下外加鈣離子處理會促進GABA含量增加。總結上述結果，台灣藜幼苗具優良保健功效，未來能應用於芽菜等機能性食品系統之建立。

Djulis (Chenopodium formosanum Koidz.) is an native crop in Taiwan. It has been called “Hung Li” in Chinese because of its bright and red colour. Djulis is famous for being the ingredients of the kavava wine (a local wine). In addition, it contains richness nutritional contents such as high levels of dietary fiber, proteins, people-limited essential amino acids (e.g., lysine and valine) and microelement (e.g., zinc, selenium and germanium). Besides, djulis’s seed is abundant with functional components and great antioxidant activity, from betalains, which is the main source of the color in djulis and phenolic compounds. Djulis is potential for improving or preventing human’s chronic disease. Moreover, djulis’s seed also has γ-aminobutyric acid (GABA) , a free amino acids, which is the major inhibitory neurotransmitter in the mammalian central nervous system. The GABA is helpful for the central nervous system to regulate physiological function such as controlling stress, transquilizer effects, induction of anti-hypertensive, prevention of diabetes, etc. Due to djulis’s extraordinary values, it has become more and more popular. However, most people just eat seed. Studies show that seed germination induce its functional components and antioxidant activity, which means more effective. Especially, the content of GABA also been induced after germination. The stress is also a factor of GABA increasing. The object of this study is to investigate the effects of temperature, seeding days and salt stress treatment on djulis functional components and antioxidants capacities. The study is divided into three parts. First of all, growth temperature treatment with 18, 24 and 30℃. Secondly, seeding days, which ranges from 1-7 days. The final treatment is salt stress, with four concentrations (50, 100, 150 and 200 mM). Results revealed that djulis sprouts in high temperature (30℃) had the highest amounts of secondary metabolites and in low temperature (18℃) had the highest antioxidant capacities. The antioxidants capacities of djulis sprouts in temperature treatment might be constituted by phenolic compound due to significant positive correlation. When seeding days was up to fifth or sixth days, the sprouts turned out to have the highest functional components and antioxidant capacities. At that time, all of the functional components were correlated to djulis sprouts’ antioxidant capacities. The salt stress treatment revealed that moderate salinity could increase physiological performance, the amounts of functional components and antioxidants capacities. Exogenous calcium when application of salt stress could induce GABA content. To sum up, djulis sprouts have great health benefits. The results can be applied to establish the djulis sprout production system.