Bamboo leaf extract treatment alleviates the surface browning of fresh-cut apple by regulating membrane lipid metabolism and antioxidant properties.

BACKGROUND: The effect of bamboo leaf extract (BLE) on controlling the browning of fresh-cut apple stored at 4 °C was investigated. Browning index, H2 O2 content, O2 - production rate, malondialdehyde (MDA) contents, total phenolic content (TPC) and soluble quinone content (SQC), the activities of polyphenol oxidase (PPO), peroxidase (POD), lipoxygenase (LOX), superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), DPPH (2,2-diphenyl-2-picryl-hydrazyl) and ABTS [2,2-azinobis(3-ethylbenzothiazoline- 6-sulfonic acid)] radical scavenging activities, and the expression of genes related to browning were all investigated. RESULTS: BLE effectively alleviated the surface browning of fresh-cut apple, accompanied by a reduction in SQC, LOX activity, H2 O2 , O2 - production rate and MDA accumulation. Furthermore, BLE treatment enhanced the TPC, enzymatic (SOD, CAT, APX and POD) and non-enzymatic antioxidant activities. Principal component analysis and Pearson correlation analysis found the browning inhibition by BLE is not through the reduction of phenolic substrates and PPO activity. CONCLUSION: BLE controls the browning of fresh-cut apple by increasing the antioxidant capacity to scavenge ROS, which could alleviate oxidative damage and maintain the membrane integrity. © 2023 Society of Chemical Industry.

Integration of transcriptome, miRNA and degradome sequencing reveals the early browning response in fresh-cut apple.

Surface browning negatively impacts the shelf-life of fresh-cut apple. Herein, we found that the browning of fresh-cut apple aggravated rapidly after 24 h post-cutting, then the transcriptomic and miRNA expression profiles of fresh-cut apple immediately after cutting (T0) and 24 h post-cutting (T24) were analyzed to explore the molecular mechanism of early browning response. A total of 3156 differentially expressed mRNAs (DEGs) and 23 differentially expressed miRNAs (DEmiRNAs) were identified in T24 vs T0. Most DEGs related to respiratory, energy, antioxidant, lipid and secondary metabolism were activated in the early stage of browning. There were 63 target genes of 10 DEmiRNAs validated by degradome sequencing and among them, mdm-miR156aa_L + 1_1 targets 12-oxophytodienoate reductase, ptc-miR6478_R-1 targets patatin-like protein, mdm-miR156aa_L + 1_1 and mdm-miR156aa_L + 1_2 co-target SPLs might participate in the early browning response through regulating antioxidant, lipid and secondary metabolism. Our results will be beneficial for the technological innovation of browning amelioration for fresh-cut apple.