Reduction of browning in minimally processed lettuce ( Lactuca sativa L.)

Abstract

The investigation was carried out to assess the effect of post-harvest dip treatment of melatonin (10, 100 and 1000 μmol L-1) on shelf life and sensory qualities of minimally processed fresh cut lettuce, kept at 6±2ºC for 8 days. Melatonin treatment was found effective in maintaining freshness and sensory qualities of lettuce during storage. Browning was reduced by 45% with 44.10% higher visual quality index in 100 μmol L-1 melatonin treated samples than control at the 6th day of storage. Maximum total chlorophyll, phenol and antioxidants, with least activity of browning related enzyme i.e. peroxidase (POD) was also observed in 100 μmol L-1 melatonin treated samples during the course of storage duration. No significant variation was observed between melatonin @ 10 μmol L-1 treated and control samples. Browning index value had significant negative correlation with total chlorophyll, phenol and antioxidants whereas POD activity had significant positive correlation. It can be inferred from the present investigation that post harvest treatment of 100 μmol L-1 melatonin maintained the quality of minimally processed lettuce for 6 days storage at 6±2ºC temperature.