A simplified UV spectral scan method for the estimation of phenolic acids and antioxidant capacity in eggplant pulp extracts

The objective of this study was to determine if a simple UV spectral analysis method can be used as a screening tool to estimate the amount of phenolic acid and the antioxidant capacity of eggplant pulp extracts. Calibration curves for different concentrations of 5-O-caffeoylquinic acid standards were developed using UV spectral data, HPLC analysis, and ferric reducing antioxidant power (FRAP) assay. Seven different freeze-dried eggplant pulp samples belonging to different cultivars or grown under different environmental conditions along with single peel sample were selected as model substrates for this study. HPLC results, simple UV spectral scan data, and quantification of antioxidant capacity by FRAP assay in seven eggplant pulp extracts showed a strong correlation (R2 > 0.9) between the three methods. These results suggest that the single absorption reading or a simple UV spectral scan can be used to estimate the concentration of phenolic acids and the antioxidant capacity in eggplant pulp extracts without peels. This screening tool can be potentially used to identify cultivars and growing conditions that influence phenolic acid content in eggplant samples.

► Simple UV spectral analysis can be used as a screening tool to estimate phenolic acids content in eggplant pulp extracts.
► Correlation between HPLC analysis, UV spectral scan data, and antioxidant capacity by FRAP assay was evaluated.
► Results with limited number of eggplant pulp extracts showed a strong correlation (R2 > 0.9) between the three methods.