제주감귤을 이용한 발효주 개발과 바이오에탄올 생산

Abstract

PART I. Development of Wine with Jeju-Citrus Various yeast strains were tested, and the sterilization methods of citrus juice and citrus juice concentrate were optimized for making citrus wine. In addition, changes in the physicochemical characteristics of the wine during its fermentation were analysed. Citrus juice contained 10.53/100g vitamin C and 0.53% titratable acidities. In citrus extract, Concentrations of vitamin C (14.01㎎/100g) and titratable acidities (0.60%) were higher than in citrus juice The yeast strain Saccharomyces cerevisiae WY30 was selected for the fermentation of citrus extract. To find suitable conditions for alcohol fermentation, we attempted various conditions such as sugar concentration, nitrogen source and hesperidin concentration. The sugar concentration of citrus concentrate 10% was adjusted to 25% with sucrose, and 0.1% of (NH₄)H₂PO was added for a nitrogen source. 10-500 ㎍/mL of hesperidin was added to increase the antioxidant activity and to make healthful wine. Hesperidin is a flavanone glycoside found abundantly in citrus fruits and acts as an antioxidant. After 30 days of fermentation at room temperature(℃), the concentration of alcohol was 14.8-15.1% in citrus wine. During fermentation, sugar concentration was decreased to 8.4-8.5%. Vitamin C, total phenol compound content and DPPH radical scavenging activity of citrus wine significantly increased with increasing hesperidin content.

PART II. Ethanol Production from Citrus Peel Waste Approximately 60 thousand metric tons of citrus were processed into citrus juice from farmhouse by-product. During citrus processing, about half of the fruit is expressed as juice with the rest being citrus peel waste (CPW) consisting of peels, seeds, and segment membranes. The citrus peel waste processing residues are rich in both soluble and insoluble carbohydrates which makes them an attractive potential feedstock for biological conversion to value added products. In this study, we measured the pre-treatment effect and different loadings of cellulase, pectinase and beta-glucosidase enzymes to hydrolyze citrus peel waste to produce sugars. When the loadings of commercial cellulase, pectinase and beta-glucosidase enzymes were 40EGU, 400PGU, 15Cbu to 1% peel dry matter with 50mM sodium acetate buffer pH 4.8 at 45℃ for 24h. we can obtained the highest concentration(about 74 % of total solid) of fermentable sugar. The obtain monomeric sugar medium was used for ethanol production by fermentation using a yeast strain, Saccharomyces cerevisiae.