Changes in total phenolic and flavonoid content and antioxidative activities during production of juice concentrate from Asian pears (Pyrus pyrifolia Nakai)

• Published in: Food science and biotechnology Vol. 25; no. Suppl 1; pp. 47 - 51
• Main Authors: Jiang, Gui-Hun, Nam, Seung-Hee, Yim, Sun-Hee, Kim, Young-Min, Gwak, Hyun Jung, Eun, Jong-Bang
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Society of Food Science and Technology 01.03.2016; 한국식품과학회
• Subjects: 2,2-diphenyl-1-picrylhydrazyl; antioxidant activity; antioxidants; Chemistry; Chemistry and Materials Science; cultivars; evaporation; filtration; flavonoids; Food Science; nitrates; Nutrition; packaging; pasteurization; pear juice; pears; pressing; Pyrus pyrifolia; raw fruit; seeds; washing; wastes; 식품과학; press cake; pear juice concentrate; Niitaka and Hwasan; antioxidant activity
• ISSN: 1226-7708; 2092-6456; 2092-6456
• DOI: 10.1007/s10068-016-0097-4

The total phenolic and flavonoid content and antioxidative activities during production of pear juice concentrate (PJC) from two cultivars, Hwasan and Niitaka, were investigated. The main processing steps in PJC production are washing, pressing, pasteurization, clarification, filtration, evaporation, and packaging. Total phenolic and flavonoid content of end-product PJC from Niitaka decreased by 53.11 and 46.47%, respectively, while those from Hwasan decreased by 55.46 and 36.09%, respectively, compared to the phenolic and flavonoid content of original fresh fruit. DPPH radical-scavenging activities, reducing power and nitrate radical-scavenging activities showed a similar tendency as total phenolic and flavonoid content; that is, they decreased in juice concentrate made from both cultivars. Also, antioxidant activities of press cake waste (skin and seeds) from Niitaka and Hwasan pears were higher than fresh pears. In conclusion, antioxidant levels were significantly affected during processing of PJC, especially during the pressing step in which press cake waste retains the seeds and skin.