Application of Mid-Infrared Spectroscopy for Determination of Insoluble Dietary Fiber Content in Moso Bamboo Shoot

Mid-infrared (MIR) spectroscopy was used to measure insoluble dietary fiber content (IDFC) in moso bamboo shoot. A total of 140 moso bamboo shoot samples with various IDFC levels between 0.46% and 0.213% were separated into two groups, as calibration and validation sets. Reference IDFC in moso bamboo shoot was verified using AOAC 991.43 method. MIR absorbance spectra from 400 cm(-1) to 4000 cm(-1) were collected using the calibration and validation sets. Partial least squares (PLS) analysis was performed on the calibration set, and calibration models were developed using original MIR absorbance spectra and its Savitzky-Golay first derivative spectra. Standard error of calibration (SEC) and coefficient of multiple determinations (R-2) of the calibration models were calculated to select the best model. Savitzky-Golay first derivative spectra calibration model was found to be the best, with the lowest SEC of 0.007 and highest R-2 of 0.968. This calibration model was then used to predict IDFC in moso bamboo shoots from the validation set. Predicted and reference IDFC values were compared. Relative percent deviation (RPD) and standard error of prediction (SEP) were calculated to validate the goodness of fit of the model. The Savitzky-Golay first derivative spectra calibration model gave an RPD of 3.710 with a corresponding SEP of 0.011, which indicated that MIR spectroscopy technique coupled with PLS was a rapid and accurate way for determination of IDFC in moso bamboo shoot.