Eugenol treatment delays the flesh browning of fresh-cut water chestnut (Eleocharis tuberosa) through regulating the metabolisms of phenolics and reactive oxygen species

Lijuan Zhu; Wanfeng Hu; Ayesha Murtaza; Aamir Iqbal; Jiaxing Li; Jiao Zhang; Junjie Li; Mengjie Kong; Xiaoyun Xu; Siyi Pan

doi:10.1016/j.fochx.2022.100307

Eugenol treatment delays the flesh browning of fresh-cut water chestnut (Eleocharis tuberosa) through regulating the metabolisms of phenolics and reactive oxygen species

Food Chem X. 2022 Apr 9:14:100307. doi: 10.1016/j.fochx.2022.100307. eCollection 2022 Jun 30.

Authors

Lijuan Zhu^{1

2

3}, Wanfeng Hu^{1

2

3}, Ayesha Murtaza^{1

2

3}, Aamir Iqbal^{1

2

3}, Jiaxing Li^{1

2

3}, Jiao Zhang^{1

2

3}, Junjie Li^{1

2

3}, Mengjie Kong^{1

2

3}, Xiaoyun Xu^{1

2

3}, Siyi Pan^{1

2

3}

Affiliations

¹ College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
² Key Laboratory of Environment Correlative Dietology (Huazhong Agricultural University), Ministry of Education, China.
³ Hubei Key Laboratory of Fruit & Vegetable Processing & Quality Control (Huazhong Agricultural University), Wuhan, Hubei 430070, China.

Abstract

The potential mechanism behind the browning inhibition in fresh-cut water chestnuts (FWC) after eugenol (EUG) treatment was investigated by comparing the difference in browning behavior between surface and inner tissues. EUG treatment was found to inactivate browning-related enzymes and reduce phenolic contents in surface tissue. Molecular docking further confirmed the hydrophobic interactions and hydrogen bonding between EUG and phenylalanine ammonia-lyase (PAL). Moreover, EUG also enhanced reactive oxygen species (ROS)-scavenging enzyme activities, ultimately decreasing the O₂ ^- generation rates. Regarding inner tissue, EUG induced the accumulation of colorless phenolic compounds and increased the antioxidant capacity. In conclusion, 1.5 % EUG exhibited the best inhibitory effect on FWC browning, which partly attribute to the direct inhibitory effects on PAL activity. Furthermore, EUG could also enhance the enzymatic/non-enzymatic antioxidant capacity and alleviate the ROS damage to membranes, thereby, preventing the contact between oxidative enzymes and phenols and indirectly inhibiting the enzymatic browning in FWC.

Keywords: APX, Ascorbate peroxidase; BI, Browning index; Browning; CAT, Catalase; EUG, Eugenol; Eugenol; FWC, Fresh-cut water chestnut; MDA, Malondialdehyde; MIO, 4-methylidene-imidazole-5-one; Molecular docking; PAL, Phenylalanine ammonia-lyase; PBS, Sodium phosphate buffer; POD, Peroxidase; PPO, Polyphenol oxidase; Phenolics metabolism; Phenylalanine ammonia-lyase; ROS, Reactive oxygen species; Reactive oxygen species metabolism; SOD, Superoxide dismutase; T-AOC, Total antioxidant capacities; TPC, Total phenols content; Water chestnut.