Comparison of the biochemical properties and thermal inactivation of polyphenol oxidase from three lily bulb cultivars

Xinyu Wang; Lvzhu Yang; Jie Liu; Rongrong Wang; Qun Zhang; Yang Shan; Shenghua Ding

doi:10.1111/jfbc.13431

Comparison of the biochemical properties and thermal inactivation of polyphenol oxidase from three lily bulb cultivars

J Food Biochem. 2020 Oct;44(10):e13431. doi: 10.1111/jfbc.13431. Epub 2020 Aug 17.

Authors

Xinyu Wang^{1

2}, Lvzhu Yang^{1

2}, Jie Liu^{1

2}, Rongrong Wang³, Qun Zhang^{1

2

4}, Yang Shan^{1

2

4}, Shenghua Ding^{1

2

4}

Affiliations

¹ Longping Branch Graduate School, Hunan University, Changsha, China.
² Hunan Agricultural Product Processing Institute, Hunan Academy of Agricultural Science, Hunan Provincial Key Laboratory for Fruits and Vegetables Storage Processing and Quality Safety, Changsha, China.
³ College of Food Science and Technology, Hunan Agricultural University, Changsha, China.
⁴ Hunan Province International Joint Lab on Fruits & Vegetables Processing, Quality and Safety, Changsha, China.

PMID: 33090543
DOI: 10.1111/jfbc.13431

Abstract

The biochemical properties and thermal inactivation of polyphenol oxidase (PPO) from three main planted lily cultivars in China, namely, Lilium lancifolium Thunb, Lilium brownie var. viridulum, and Lilium davidii var. unicolor cotton were evaluated. Data indicate that the PPO from three cultivars showed two optimum pH levels of 4.0 and 6.5-7.0 and temperature of 15°C and exhibited the highest affinity toward 4-methylcatechol. However, this enzyme did not exhibit monophenolase activity. Thiourea and L-cysteine were more effective than other inhibitors. The enzymatic activity of L. lancifolium Thunb PPO crude extract was higher than that of L. brownie var. viridulum and L. davidii var. unicolor cotton. For thermal inactivation, L. davidii var. unicolor cotton PPO showed the best thermal resistance at 65-75°C, and L. lancifolium Thunb showed stability at 45°C. The deactivation of the three types of PPO followed the first-order reaction kinetics, and the activation energy (E_a) was 144.28, 138.00, and 107.12 kJ/mol for L. lancifolium Thunb PPO, L. brownie var. viridulum PPO, and L. davidii var. unicolor cotton PPO, respectively. PRACTICAL APPLICATIONS: Lilium is an ornamental and edible plant typically used for food and traditional Chinese medicine. Its flowers are used for decoration, and its underground bulbs are rich in various bioactive substances. Fresh lily bulbs easily turn brown and lose economic value during storage and processing. Polyphenol oxidase (PPO) is a crucial molecule involved in the enzymatic browning of fruit and vegetables. In this study, PPO was extracted from three main planted lily cultivars in China. Namely, Lilium lancifolium Thunb, Lilium brownie var. viridulum, Lilium davidii var. unicolor cotton and was partially characterized. The results are of considerable importance to further understand the PPO of lily bulbs and provide guidance for the inactivation of enzymes and the processing of lily bulb juice.

Keywords: inhibitor; lily bulbs; polyphenol oxidase; substrate specificity; thermal inactivation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Catechol Oxidase
China
Lilium*
Oxidation-Reduction
Plant Roots

Substances

Catechol Oxidase