Table 3. Partial least square regression model-based calibration and cross-validation results of 17 quality parameters of mackerel fillets measured using hyperspectral imaging during six days of storage

Target	N	Calibration		Cross-validation
		R2C	RMSEC	R2CV	RMSECV	RPDCV
pH	11	0.96	0.06	0.86	0.12	2.64
Cohesiveness	18	0.99	0.00	0.69	0.03	1.80
TBARS	11	0.91	0.91	0.64	1.83	1.66
Elasticity	12	0.91	0.00	0.63	0.01	1.64
VBN	10	0.87	0.91	0.57	1.67	1.53
K-value	9	0.85	3.05	0.48	5.73	1.39
Hardness	4	0.57	16.19	0.47	17.89	1.38
Springiness	4	0.55	0.04	0.45	0.05	1.35
Dark muscle CIE a*	8	0.74	1.17	0.36	1.86	1.25
White muscle CIE b*	6	0.55	0.79	0.31	0.98	1.20
Dark muscle H	6	0.53	3.09	0.26	3.89	1.16
White muscle CIE a*	6	0.55	1.25	0.19	1.68	1.11
Gumminess	5	0.61	6.57	0.19	9.44	1.11
White muscle CIE L*	5	0.38	3.44	0.17	3.98	1.09
Adhesiveness	3	0.31	0.13	0.16	0.15	1.09
White muscle H	6	0.54	4.18	0.15	5.66	1.09
Chewiness	5	0.54	4.01	0.10	5.64	1.05

N, latent variables; R²_C, coefficient of calibration; R²_cv, coefficient of cross-validation; RMSEC, root-mean-square errors estimated by calibration; RMSECV, root-mean-square errors estimated by cross-validation; RPD_CV, relative percent difference of cross-validation; TBARS, 2-thioabarbituric acid reactive substances; VBN, volatile basic nitrogen; H, hue angle.