酵母菌共發酵於巨峰葡萄酒類釀造之研究

Abstract

摘要 葡萄種植與釀酒文化在許多國家具有重要的經濟與歷史地位。臺灣是地理獨立的區域，獨特且多元的微生物菌相為酒類釀造提供了良好的基礎。本土菌株的篩選與高品質的葡萄適合進行臺灣在地葡萄酒的研發。本研究的目的為利用臺灣盛產的巨峰葡萄與在地微生物進行酒類釀造。研究方向分為三個階段：(1) 從臺灣篩選酵母菌並探討其釀酒特性與香氣圖譜 (2) 藉由菌株共培養接種策略改善酒類香氣 (3) 使用加烈與熟成技術增進酒類品質。 從臺灣水果中鑑定並篩選出 4 株具有釀酒潛力的菌株，Saccharomyces cerevisiae Gr112、Pichia kluyveri Pe114、Hanseniaspora uvarum Pi235 和Hanseniaspora guilliermondii Ki135。S. cerevisiae Gr112具有優秀的乙醇轉換率與B-葡萄糖苷酶活性，P. kluyveri Pe114 具有良好的二氧化硫耐受性，而所有non-Saccharomyces 酵母菌皆顯示了出色的酯類生產能力。在香氣圖譜分析中，由於 H. uvarum Pi235 和 H. guilliermondii Ki135具有相似的圖譜，釀酒實驗只採用 H. uvarum Pi235 進行。 共培養研究中，使用多種菌株接種策略，包括兩株菌與三株菌的同時接種與順序接種。在巨峰酒的儀器分析與品評結果中，適當的共培養策略可以改善 non-Saccharomyces 酵母菌發酵造成的負面異味與 S. cerevisiae Gr112 生產過量的高級醇，同時提升酒中花香、紅色果香與熱帶果香，使風味層次更加豐富並提升酒類整體品質。 在巨峰加烈酒與熟成實驗中，使用共培養發酵策略，結合加烈技術與90天的橡木熟成。共培養技術為巨峰加烈酒提供了豐富的酯類與萜烯類香氣化合物，使其具有令人愉悅的熱帶水果香氣與花香。加烈與熟成技術突顯巨峰酒的莓果香氣與木質香氣。這些製程都提升了巨峰加烈酒的品質，並在品評結果中獲得了臺灣消費者的青睞。 以上研究說明了臺灣巨峰葡萄與本土酵母菌株具有優秀臺灣風土酒類釀造的潛力，經由菌株篩選、共培養、加烈與熟成技術，使巨峰加烈酒具有突出的風土特徵。總結來說，種菌研發與發酵產品應用的可能性不容小覷，具臺灣風土特徵的發酵產品更是未來趨勢。

ABSTRACT Viticulture and oenology play important economic and historical roles in various regions around the world. In Taiwan, the geographically independent region combined with diverse microorganisms create a good foundation for winemaking. Consequently, it is plausible to produce unique Taiwanese terroir wines with the local microorganisms and high-quality grapes. The purpose of this study is to employ local yeast strains and Kyoho grapes for wine research. This investigation can be divided into 3 stages: First, yeast strains from the natural environment of Taiwan are screened to determine oenological characteristics as well as aroma profile. Second, wine aroma profile is improved through the yeast strains inoculation strategy. Third, wine quality is enhanced through fortification and ageing technology. In the yeast screening process, four yeast strains with winemaking potential were identified and screened from fruits. They were Saccharomyces cerevisiae Gr112, Pichia kluyveri Pe114, Hanseniaspora uvarum Pi235, and Hanseniaspora guilliermondii Ki135. While S. cerevisiae Gr112 had high ethanol conversion rate and B-glucosidase activity, P. kluyveri Pe114 had good sulfur dioxide tolerance; all non-Saccharomyces yeasts showed excellent ester production ability. In the aroma profile analysis result, only H. uvarum Pi235 was chosen in subsequent winemaking experiments because H. uvarum Pi235 and H. guilliermondii Ki135 shared similar profiles. During the co-cultivation study, a variety of yeast strain inoculation strategies were carried out, including simultaneous inoculation and sequential inoculation of two strains and three strains. In sensory evaluation and instrumental analysis results, an appropriate inoculation strategy could remove solvent and undesirable off-odor caused by non-Saccharomyces yeast fermentation, as well as reduce the excessive production of higher alcohol by S. cerevisiae. Furthermore, the technique also enhanced the floral, red fruity, and tropical fruity aromas, which improved the flavor and overall quality of wine. In Kyoho fortified wine making experiment, co-cultivation fermentation was implemented with fortification and 90-day oak ageing. The co-cultivation strategy provides abundant ester and terpene volatile aroma compounds for Kyoho fortified wine which creates pleasant tropical fruity and floral aromas. Additionally, fortification and aging techniques highlight the berry and woody aromas of Kyoho fortified wine. These processes can improve complexity and quality of the fortified wine which contribute to positive evaluation results from Taiwanese consumers. These research investigations indicate that Taiwanese Kyoho grapes and native yeast strains possess excellent potentials to produce Taiwanese terroir wines. Through yeast strains screening, co-cultivation, fortification, and ageing techniques, Kyoho fortified wines have outstanding terroir characteristics. In conclusion, the fermentation technology and research of microorganisms are highly applicable, and the strategies can be utilized to ferment other products.