Abstract: The effects of methyl jasmonate (MeJA) on the quality and antioxidant activity of fresh-cut pineapples during storage were investigated. Intact pineapples were fumigated with 0, 1, 10 or 100 μmol/L MeJA at 20 ℃ for 12 h, then cut into pieces and stored at 15 ℃ for 48 h. The results indicated that MeJA treatment promoted the increases of total phenol content and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, inhibited the decrease of total soluble solid and titratable acid content, but had no significant effect on color or total plate count (P > 0.05). Moreover, treatment with 10 μmol/L MeJA was the most effective in improving the activities of phenylalanine ammonia-lyase and cinnamate- 4-hydroxylase, delaying the decrease of 4-coumarate-CoA ligase, thereby promoting the accumulation of total phenols and total flavonoids and enhancing the DPPH radical scavenging activity of fresh-cut pineapples during storage. These results suggest that MeJA treatment can maintain the quality and improve the antioxidant activity of fresh-cut pineapples.

Key words: methyl jasmonate, fresh-cut pineapples, phenylalnine ammonialyase, cinnamate-4-hydroxylase, 4-coumarate-CoA ligase, antioxidant activity