Cod peptides inhibit browning in fresh-cut potato slices: A potential anti-browning agent of random peptides for regulating food properties

Enzymatic browning is a major industrial problem of fresh-cut vegetables and fruits. Bioactive peptides are safe, nutritive and low-cost sources of antioxidant and antimicrobial agents. However, there has been little research on the effect of random peptides on anti-browning of fresh-cut food. For developing more natural and nutritive anti-browning agents, the effect of the enzymatic hydrolysis of random peptides from cod fish skin on polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia-lyase (PAL), total phenolic content, membrane permeability, malondialdehyde (MDA) content and color changes were investigated during fresh-cut potato storage. The results showed that 0.1% (w/w) cod peptides efficiently blocked enzymatic browning by inhibiting PPO, POD and PAL activities, reducing the total phenol accumulation during the entire 8 d storage at 4 °C. Furthermore, the membrane permeability and MDA content increases were delayed in 0.1% cod peptides treatment compared with the control. Oddly, the browning of fresh-cut potato was aggravated in 1.0% cod peptides treatment, which expressed higher POD and PAL activities. Meanwhile, the functional composition of cod peptides was a random component, which total 1765 peptides were identified by LC-MS/MS and the amino acids length of peptides were 4∼57 in the cod peptides. All the results showed that random peptides might be promising candidates as anti-browning agents for fresh-cut potato slices.