Rapid Fruit Extracts Antioxidant Capacity Determination by Fourier Transform Infrared Spectroscopy

om 5 blueberry, 5 grape, and 6 blackberry genotypes were obtained by methanol-water-formic acid (60:37:3, v/v/v) solvent. The grape, and 6 blackberry genotypes were obtained by methanol-water-formic acid (60:37:3, v/v/v) solvent. The grape, and 6 blackberry genotypes were obtained by methanol-water-formic acid (60:37:3, v/v/v) solvent. The grape, and 6 blackberry genotypes were obtained by methanol-water-formic acid (60:37:3, v/v/v) solvent. The grape, and 6 blackberry genotypes were obtained by methanol-water-formic acid (60:37:3, v/v/v) solvent. The total antio total antio total antio total antio total antioxidant capacities of the fr xidant capacities of the fr xidant capacities of the fr xidant capacities of the fr xidant capacities of the fruit extr uit extr uit extr uit extr uit extracts w acts w acts w acts w acts wer er er er ere determined b mined b mined b mined b mined by the ORA y the ORA y the ORA y the ORA y the ORAC FL FL FL FL assay, and the FTIR spectr , and the FTIR spectr , and the FTIR spectr , and the FTIR spectr , and the FTIR spectra of the a of the a of the a of the a of the fruit extracts were collected. Partial least squares (PLS) regressions with cross-validation was conducted on 128 fruit extracts were collected. Partial least squares (PLS) regressions with cross-validation was conducted on 128 fruit extracts were collected. Partial least squares (PLS) regressions with cross-validation was conducted on 128 fruit extracts were collected. Partial least squares (PLS) regressions with cross-validation was conducted on 128 fruit extracts were collected. Partial least squares (PLS) regressions with cross-validation was conducted on 128 spectra of extracts and their corresponding ORAC spectra of extracts and their corresponding ORAC spectra of extracts and their corresponding ORAC spectra of extracts and their corresponding ORAC spectra of extracts and their corresponding ORAC FL values to obtain a calibration model for predicting the values to obtain a calibration model for predicting the values to obtain a calibration model for predicting the values to obtain a calibration model for predicting the values to obtain a calibration model for predicting the antioxidant activity of the extracts. Spectra from an additional 16 extracts were used as an external validation set antioxidant activity of the extracts. Spectra from an additional 16 extracts were used as an external validation set antioxidant activity of the extracts. Spectra from an additional 16 extracts were used as an external validation set antioxidant activity of the extracts. Spectra from an additional 16 extracts were used as an external validation set antioxidant activity of the extracts. Spectra from an additional 16 extracts were used as an external validation set for the model. A good calibration model ( for the model. A good calibration model ( for the model. A good calibration model ( for the model. A good calibration model ( for the model. A good calibration model (R 2 = 0.97) for antioxidant activity was obtained with satisfactory predic- = 0.97) for antioxidant activity was obtained with satisfactory predic- = 0.97) for antioxidant activity was obtained with satisfactory predic- = 0.97) for antioxidant activity was obtained with satisfactory predic- = 0.97) for antioxidant activity was obtained with satisfactory predic- tive ability (root mean standard error (RMSE) = 5.35) using the spectral region 2000/cm to 900/cm. Cross- tive ability (root mean standard error (RMSE) = 5.35) using the spectral region 2000/cm to 900/cm. Cross- tive ability (root mean standard error (RMSE) = 5.35) using the spectral region 2000/cm to 900/cm. Cross- tive ability (root mean standard error (RMSE) = 5.35) using the spectral region 2000/cm to 900/cm. Cross- tive ability (root mean standard error (RMSE) = 5.35) using the spectral region 2000/cm to 900/cm. Cross- validation procedures indicated good correlations ( validation procedures indicated good correlations ( validation procedures indicated good correlations ( validation procedures indicated good correlations ( validation procedures indicated good correlations (R 2 = 0.94) between ORAC = 0.94) between ORAC = 0.94) between ORAC = 0.94) between ORAC = 0.94) between ORAC FL FL FL FL assay values and FTIR estimates. assay values and FTIR estimates. assay values and FTIR estimates. assay values and FTIR estimates. assay values and FTIR estimates. The ratio of the standard deviation of the data to the standard error of validation (RPD) values were above 5.0 for The ratio of the standard deviation of the data to the standard error of validation (RPD) values were above 5.0 for The ratio of the standard deviation of the data to the standard error of validation (RPD) values were above 5.0 for The ratio of the standard deviation of the data to the standard error of validation (RPD) values were above 5.0 for The ratio of the standard deviation of the data to the standard error of validation (RPD) values were above 5.0 for blueberr blueberr blueberr blueberry, grapes, and the combined extr , and the combined extr , and the combined extr , and the combined extr , and the combined extracts in the exter acts in the exter acts in the exter acts in the exter acts in the external v nal v nal v nal v nal validation set indicating that the calibr alidation set indicating that the calibr alidation set indicating that the calibr alidation set indicating that the calibr alidation set indicating that the calibration model ation model ation model ation model ation model was suitable for quantifying fruit extracts antioxidant activities. This study shows that an FTIR technique would was suitable for quantifying fruit extracts antioxidant activities. This study shows that an FTIR technique would was suitable for quantifying fruit extracts antioxidant activities. This study shows that an FTIR technique would was suitable for quantifying fruit extracts antioxidant activities. This study shows that an FTIR technique would was suitable for quantifying fruit extracts antioxidant activities. This study shows that an FTIR technique would be suitable for r be suitable for r be suitable for r be suitable for r be suitable for rapidly measur apidly measur apidly measur apidly measur apidly measuring fr ing fr ing fr ing fr ing fruit extr uit extr uit extr uit extr uit extract antio act antio act antio act antio act antioxidant activity xidant activity xidant activity xidant activity xidant activity. K K K Keywor eywor eywor eywords: FTIR, antio ds: FTIR, antio ds: FTIR, antio ds: FTIR, antio ds: FTIR, antioxidant capacity xidant capacity xidant capacity xidant capacity xidant capacity, fr , fr , fr , fruit extr uit extr uit extr uit extr uit extracts