cryst (version 0.1.0)

fitFTIRc: Relative Crystallinity Calculation of FTIR Spectrum of Starch by SUN Method

Description

Allow to calculate the relative crystallinity of starch by FTIR. The basic concept of SUN approach involves obtaining a gaussian holocrystalline-peak in the 800-1300 cm-1 region of FTIR spectrum of starch which is divided into amorphous region and crystalline region.

Usage

fitFTIRc(spectrum, mu = 1180, sigma = 60, k = 1, lim = c(1190, 1160, 985, 950))

Arguments

spectrum

matrix. The matrix of FTIR spectrum baseline-corrected by drawing a tangentline in the 800-1300 cm-1 region. The first row corresponds to wavelength; the second row corresponds to intensity.

mu

numeric. Gaussian mean of holocrystalline-peak. Defaults to 1180.

sigma

numeric. Standard deviation of holocrystalline-peak. Defaults to 60.

k

numeric. Arbitrary scaling parameter. Defaults to 1.

lim

vector. Fitting points of holocrystalline-peak. Defaults to c(1190, 1160, 985, 950).

Value

An object of class fitFTIRc, which is a list with the following components:

Details

Calculate the relative starch crystallinity of FTIR spectrum by SUN method.

References

Sun, Y., et al. (2014). "A new method for determining the relative crystallinity of chickpea starch by Fourier-transform infrared spectroscopy." Carbohydrate Polymers 108: 153-158.

Examples

# Convert data frame to matrix, select A-type starch
spectrum <- as.matrix(t(FTIR[, c('wavelength','A')]))
# List of crystallinity components
crs <- fitFTIRc(spectrum = spectrum, mu = 1180, sigma = 60, k = 1, lim = c(1190, 1160, 985, 955))
# Original matrix
original <- crs$original
# Gaussian curve fit
gauss <- crs$gauss
# Summary of Non-Linear Least-Squares Model Fits
fit <- crs$fit
# Summary calculation of crystallinity
summary <- crs$summary