荔枝氣泡酒製程之研究

Abstract

荔枝為我國重要經濟果樹之ㄧ，由於產期短且不易保鮮，常造成產銷問題，故研製新產品以增加荔枝的加工利用有其必要。本研究以黑葉種荔枝為原料，探討荔枝氣泡酒之最適製程。 傳統氣泡酒製程為兩段式發酵，先經一次發酵(主發酵)製得基酒，再以二次發酵產生二氧化碳，使酒中富有細緻而持久之氣泡。主發酵條件經試驗後確認為荔枝原汁調糖至22 ºBrix，添加檸檬酸 (l.0 g/L) 及亞硫酸鹽(使游離二氧化硫濃度達200 ppm)，並接種Danstil D (Saccharomyces cerevisiae)，於25 ºC下發酵七天，製得荔枝發酵基酒。荔枝基酒再分別以傳統法，即添加25 g/L蔗糖及100 ppm亞硫酸鹽，並接種Fermivin PDM (Saccharomyces bayanus) 於15 ºC下進行二次發酵；或固定化酵母發酵法，即接種經3 %褐藻酸鈉固定化之酵母細胞進行二次發酵；或直接充填高壓二氧化碳使其最終壓力達5 kg/cm²，製成荔枝氣泡酒。 三種不同製程所得之成品經熟成六個月後分析比較，高壓氣體充填法所製得之荔枝氣泡酒氣泡粒徑較大；於濁度方面，以高壓氣體充填法及固定化酵母發酵法所製得之荔枝氣泡酒皆低於傳統發酵法；經喜好性品評試驗結果得知，在外觀方面，固定化酵母發酵法及高壓氣體充填法皆優於傳統法，在風味及口感方面，固定化酵母發酵法與傳統發酵法並無顯著差異，皆優於高壓氣體充填法。整體喜好性上，以固定化酵母發酵法有最高之接受度，其次為傳統法。確認二次發酵最適製程為荔枝基酒添加25 g/L蔗糖及100 ppm亞硫酸鹽，並接種經3 %褐藻酸鈉固定化之酵母Fermivin PDM ( Saccharomyces bayanus ) (膠體起始菌數：108 cells/mL，顆粒大小：2~3 mm) 8 g/每瓶600 mL於 15 ºC下進行發酵。以固定化酵母發酵法所製造之荔枝氣泡酒能免除傳統製程中的轉瓶步驟，縮短製程時間，並保有良好之風味口感。

Lychee is an important fruit in Taiwan. There are some problems in production and marketing because lychee has a short harvesting period and difficult to store. So it is justified to improve its utilization by making new product. The project was to establish a suitable process for making sparkling lychee wine. Traditional method for the making of sparkling wine involves two steps of fermentation. The base wine is produced in the first step, called the primary fermentation. The secondary fermentation follows, and generates fine, sustainable bubbles in the wine. An adequate procedure for the primary fermentation was found to be adding sucrose, citric acid and sulfite to lychee juice to reach 22 ºBrix, 1.0 g/L and 200 ppm SO2 concentration, respectively, inoculating Saccharomyces cerevisiae Danstil D, and then incubating at 25 ºC for 7 days to obtain lychee base wine. The base wine can be added with 25 g/L sucrose and 100 ppm sulfite, then inoculated with Saccharomyces bayanus “Fermivin PDM” and held at 16 ºC for the traditional secondary fermentation, or inoculated with yeast cells bound in 3 % sodium alginate for the immobilized secondary fermentation. The base wine can also be infused with carbon dioxide to reach 5 kg/cm² pressure level in the production of sparkling wine in an alternative way. Both of the sparking wines produced by the carbon dioxide infusion method and by the immobilized yeast fermentation method have a lower turbidity than the one produced by the conventional fermentation method. There is no significant difference in flavor and mouth feel between the products from the immobilized yeast fermentation and from the conventional fermentation. However, both of the bubble stability and the acceptance of the sparkling wine produced by the carbon dioxide infusion method are inferior to those of the products produced by the other two methods. We concluded that to produce sparkling lychee wine by immobilized yeasts enjoys the advantage of being exempted from the tedious riddling operation in the conventional method, shortening the process time, yet retaining good flavor and taste; and therefore is worth to be recommended.