Ultrasonication – A complementary ‘green chemistry’ tool to biocatalysis: A laboratory-scale study of lycopene extraction

Lycopene is bequeathed with multiple bio-protective roles, primarily attributed to its unique molecular structure. The concomitant exploitation of two of the green chemistry tools viz., sonication and biocatalysis is reported here for the laboratory scale extraction of lycopene from tomato peel. The coupled system improved the extraction by 662%, 225% and 150% times over the unaided, only cellulase ‘Onozuka R-10’ treated and only sonication treated samples respectively. The sonication parameters (duration, cycle and amplitude) during the coupled operation were optimized using response surface methodology (RSM). Derivative UV–visible spectra (i.e., dA/dλ and d2A/dλ2 against λ), FTIR analysis, and DPPH scavenging test suggested that the reported extraction protocol did not affect the molecular structure and bioactivity of the extracted lycopene. The influence of sonication on the probable structural modulation (through UV–visible spectral analysis) and activity of the enzyme were also analyzed. A plausible mechanism is proposed for the enhanced extraction achieved via the coupled system.

► Sonication significantly enhances biocatalytic extraction of tomato-peel lycopene.
► Duration, cycle and percent amplitude of sonication profoundly affects extraction.
► Sonication reduces the amount of enzyme used and incubation time.
► Extracted lycopene retains the structural integrity and DPPH scavenging potency.