Metabolite profiling of sugar and phenolics provide clues for postharvest anthocyanin accumulation in detached leaves of lemon balm for possible utilization in food products

Abstract

Melissa officinalis L., an aromatic herb is commonly known as lemon balm for its lemon fragrance. This study reports the outcome of simulation experiment conducted inside the plant growth chamber followed by conducting the same experiment in realtime condition in open environment for 21 days to see the response of postharvest lemon balm leaves in accumulating anthocyanin pigments. Detached leaves were found to accumulate anthocyanin up to 21 days in both the cases. Simulation experiment showed cyanidin concentration of 2.36 ± 0.37 g Kg-1 whereas it was 1.78 ± 0.49 g Kg-1 in realtime experiment. The accumulated anthocyanin appeared stable in different buffer solutions with variable pH ranges. Further, degradation of the major internal pool of volatile was observed in both the cases. However, rosmarinic acid content was found to be increased in realtime experiment in comparison to simulation experiment which was just unlike of cyanidin. Several primary metabolites mostly sugars were found to be varied between the detached leaves generated from the two experiments. Sucrose was found to be the highest contributors among all the primary metabolites detected in red leaves from simulation experiment whereas it is talose in the case of realtime experiment. Various food products were also prepared from these value-added leaves to demonstrate its immediate application potential.