Near-Infrared Spectroscopy and Chemometrics for the Routine Detection of Bilberry Extract Adulteration and Quantitative Determination of the Anthocyanins

Table 1

Summary of the NIRS calibration model statistics.

Parameters	ACN content in bilberry extracts
ACN content	% dried matter
SEL	0.31
N	38
Outliers	0
Min	18.8
Mean	24.2
Max	33.2
SD	4.1
RMSEE	0.28
r^2	99.63
RPD	12.5
RANK	8
Segments/range (cm^−1)	2/9400–6096, 5456–4248
Acquisition range (cm^−1)/step	4000–12500/8
Pretreatments tested	NSDPP, CO, MSC, 1stDer, 2ndDer, VN, SLS, MMN, RO, 1stDer + SLS, 1stDer + VN, and 1stDer + MSC
Pretreatments used	SLS
Regression method	PLS
Threshold	0.353
Mahalanobis distance	0.91

N: number of samples; NSDPP: no spectral data preprocessing; CO: constant offset elimination; MSC: multiplicative scatter correction; 1stDer: first derivative; 2ndDer: second derivative; VN: vector normalization; SLS: straight line subtraction; MMN: minimum maximum normalization; RO: rank optimization.