Fresh-cut apples often undergo browning and lignification during processing, resulting in quality deterioration and a shortened shelf life. In May 2022, a research team from Shanghai Ocean University and the Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences treated fresh-cut apples with 0.8% (v/v) phytic acid to improve their storage quality and extend shelf life.

 

The results showed that phytic acid treatment effectively inhibited browning. On day 2 of storage, the browning index (BI) of the control fruit was 1.62 times that of the phytic acid-treated group. Compared with the control group, the lignin content of the phytic acid-treated fruit was significantly reduced on days 2, 4, and 6 of storage. Meanwhile, phytic acid treatment decreased the contents of hydrogen peroxide (H₂O₂) and malonaldehyde (MDA), indicating slighter damage to the cell membrane of apples.

 

Compared with the control group, the activities of polyphenol oxidase (PPO) and peroxidase (POD) decreased, while the activities of superoxide dismutase (SOD) and catalase (CAT) increased in the phytic acid-treated fruit. Consistent with the change in lignin content, phytic acid treatment also inhibited the activities of phenylpropane metabolism-related enzymes, namely phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H), and 4-coumarate: CoA ligase (4CL).

 

In conclusion, phytic acid alleviated browning and lignification of fresh-cut apples by reducing the activities of PPO and POD, maintaining cell membrane integrity, and inhibiting phenylpropane metabolism.

 

 

 

What is the optimal concentration of phytic acid for treating fresh-cut apples and what is its core preservation effect? Answer: Fresh-cut apples are soaked in 0.8% (v/v) phytic acid for 10 minutes. The core effects are inhibiting browning and lignification, extending the shelf life of fresh-cut apples to 4 days at 4 °C, while maintaining cell membrane integrity and sensory quality.

 

 

What are the molecular and physiological mechanisms by which phytic acid inhibits browning of fresh-cut apples? Answer: ① Directly inhibits the activities of PPO and POD to reduce phenol oxidation; ② Improves the activities of SOD and CAT to scavenge reactive oxygen species such as H₂O₂; ③ Reduces MDA accumulation to protect cell membrane structure and reduce contact between enzymes and substrates.

 

 

How does phytic acid reduce lignification of fresh-cut apples and which key enzymes are involved? Answer: Phytic acid reduces lignification by inhibiting the phenylpropane metabolic pathway. The key target enzymes are PAL, C4H, and 4CL. The decreased activities of these three enzymes reduce the precursors for lignin synthesis, ultimately lowering lignin accumulation and tissue lignification.

 

 

 

Journal: Foods Title: Phytic Acid Treatment Inhibits Browning and Lignification to Promote the Quality of Fresh-Cut Apples during Storage DOI: https://doi.org/10.3390/foods11101470