Preparation of Pear Wines and Analysis of Their Functionality

• Main Authors: Hsiang-Yun Chan, 詹湘澐
• Other Authors: Wen-Ching Ke
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/67156844673802484413

碩士 === 大葉大學 === 生物科技碩士在職學位學程 === 102 === Xinxing pear, one kind of sandy pears (Pyrus pyrifolia Nakai ), abound in Cholan town in Miaoli County were prepared as (1) peeled and cored, (2) leaved peel but cored, (3) cooked pulp adjusted soluble solid at 40OBrix, (4) cooked pulp adjusted soluble solid at 70OBrix. Four materials were individually fermented, and the quality of the brewed alcoholic beverages was determined. The results were as follows: 1. The basic processes for making brewed alcoholic beverages from four forms of pear materials were established. Through the processes as adjusting soluble solid at 25OBrix, stewing 2 hours after adding potassium metabisulfite (as 100 ppm sulfur dioxide), fermenting 14 days by adding 0.03% commercial yeast, final products in 13-16% alcohol could be obtained. 2. Products made from pear leaved peel but cored showed the highest level of reducing activity 0.911, while the lowest for that from peeled and cored pear (0.76). This phenomenon possibly resulted from the ingredients contained in pear peel. On DPPH scacenging effect, the highest level was found for the product made from 40˚Brix pulp, equivalent to about 0.575 mg/mL of ascorbic acid. Total phenols gradually increased during fermentation period. Of the highest level 2.72 mg/dL (as gallic acid) for the product made from 70˚Brix pulp at 14th day. Cooking process for preparation of the material resulted in release of phenol compounds by inference. 3. The browning of the brewed alcoholic beverages could not be effectively prevented by addition of potassium metabisulfite (as 100 ppm sulfur dioxide). Combination of 0.04% sodium citrate showed marked improvement. Especially the Hunter a and b values obviously decreased and transparency increased for the products made from both 40˚Brix and 70˚Brix pulps that heat-treatment was included in the process of materials preparation.