2019 ASHS Annual Conference

Hana Jeong¹, Ha Kyeong Yoon¹, Bo-Bae Lee ², Hye-Sung Cho², Youn-Sup Cho³, Seung Hee Nam^{1, 4*}

¹ Department of Food Science & Technology, Chonnam National University, Gwangju

² Fruit Research Institute, Jellanamdo Agricultural Research and Extension Services, Chonnam, Hanam

³ Horticulture Research Institute, Jellanamdo Agricultural Research and Extension Services, Chonnam, Naju,

⁴ Institute of Agricultural and Life Science Technology, Chonnam National University, Gwangju

Yuzu is mostly consumed as traditional Korean herbal tea, preserved yuzu which is made from sliced yuzu peel and combined with sugar prepared as fruit preserves or marmalade. Yuzu is effective in preventing certain diseases owing to its anti-inflammatory, antioxidant, and anti-cancer function. In this study, we compared free sugar content, dietary fiber profiles, and phenolic contents of the fresh and preserved yuzu to find out the nutritional or functional changes by preservation. Here, preserved yuzu is produced by addition of 40% sugar (w/w) and keep at 4℃ for 6 months. Preserved yuzu contained 5~18 times higher free sugar than fresh yuzu. Fructose was 2 times higher than glucose or sucrose at fresh yuzu but not in preserved yuzu due to sucrose added for storage. For dietary fiber profiles of fresh and preserved yuzu pulp, preserved yuzu contained a fifth of dietary fiber content (7.3%) compared to that of fresh yuzu (38.2%). Interestingly, 70% of yuzu dietary fiber was transferred from pulp part to juice during sugar preservation. Dietary fiber composition was studied to measure cellulose, hemicellulose, pectin, and lignin contents. Preserved pulp had more soluble fibers like pectin or hemicellulose, instead of insoluble fiber like lignin. Fresh yuzu pulp composed of mostly pectin and lignin, meanwhile, preserved pulp had mainly hemicellulose and pectin. For functional properties, ABTS and DPPH radical scavenging activities were higher at fresh yuzu (49 µM vit C eq.) than preserved yuzu (9.1 µM vit C eq.). Total phenolic contents was 4 times higher at fresh yuzu, compared to preserved yuzu but flavonoids content (hesperinidin and naringin) by HPLC analysis was 3 times higher at preserved yuzu than fresh yuzu. Those results indicated that preserved yuzu could be a potential nutritional food source with higher soluble dietary fibers and flavonoids contents in food industry.±This study was financially supported by Rural Development Administration (Project No. PJ013826).

Keywords: Fresh yuzu, preserved yuzu, dietary fibers, antioxidant activity