Peel removal improves quality without antioxidant loss, through wound-induced phenolic biosynthesis in shredded carrot

• Peeling improves carrot shreds health benefits while preventing discoloration.
• Most carrot phenolics are concentrated in cortical and vascular tissues.
• Carrot tissues have distinct phenolic biosynthesis under wounding stress.
• Browning reactions occur mostly in peel tissues due to high PPO activity.
• Peel removal does not affect the overall phenolic synthesis of shredded carrots.

In this study we evaluated the effect of abiotic stresses, peeling and shredding, in different carrot tissues as a phenolic synthesis elicitor to improve bioactive quality of shredded carrot as a fresh-cut. The phenolic content (TPC) present in carrot peels (2954 mg kg−1) is up to ∼6 times higher than that of inner tissues (762 and 510 mg kg−1 for cortical parenchyma and vascular tissues, respectively). However, the effect of peel removal is mitigated by the respective tissue proportion in the root (∼11% for peel and ∼89% for inner tissues). Phenolic biosynthesis was verified in all carrot tissues and even when peel was removed, inner tissues were able to significantly accumulate phenolics during low temperature storage (5 °C, 10 d), with increases of 155% (compared to day 0). As key enzyme of the phenylpropanoid pathway, phenolic biosynthesis, in inner tissues, was confirmed by the phenylalanine-ammonia lyase (PAL) activity increase (p < 0.05) after wounding (peeling and shredding). It was also shown that color changes in carrot peel tissues (browning), with high polyphenoloxidase activity levels (up to 2 times regarding inner tissues), were more pronounced than in inner tissues under a high intensity wounding (shredding), showing that carrot fresh-cut production can benefit from peel removal. The use of controlled wound stresses, by increasing pre-existing raw material antioxidants, creates an opportunity to guarantee the bioactive fresh-like quality, a major challenge for fresh-cuts.