Table 3. Changes in Hunter color values of heat-treated (HT) and non-heat-treated (NHT) PVA/PAA/NR@TOCNF colorimetric indicator films (CIFs) during storage with pork at room temperature (25±2°C)

Sample	Storage period (days)	Hunter color value
Sample	Storage period (days)	L^*1)	a^*2)	b^*3)	ΔE⁴⁾
WHT-PVA/PAA/NR@TOCNF	0	40.52±2.37^5)a6)	41.06±1.08^a	−5.05±1.63^a	-
	2	51.46±4.94^c	38.21±2.35^b	−4.01±0.78^b	10.22±2.85^a
	4	47.19±1.31^b	40.67±0.49^a	−1.68±0.77^c	8.52±0.35^a
	6	51.47±0.00^c	25.85±0.00^c	29.33±0.00^d	38.94±0.00^b
HT-PVA/PAA/NR@TOCNF	0	37.09±2.38^a	31.38±2.67^b	6.61±1.22^b	-
	2	36.38±2.60^a	33.50±3.54^b	3.66±0.42^a	4.98±1.10^a
	4	35.19±0.79^a	32.93±0.40^b	2.90±0.52^a	4.03±0.01^a
	6	46.74±0.00^b	25.99±0.00^a	23.10±0.00^c	19.72±0.00^b

L^*, degree of lightness (+100=white, 0=black).
a^*, degree of redness (+100=red, −80=green).
b^*, degree of yellowness (+70=yellow, −70=blue).
ΔE^*, total color difference ([(L^*_n − L^*₀)² + (a^*_n − a^*₀)² + (b^*_n − b^*₀)²]^1/2).
All values are mean±SD (n=3).
Values with different superscript letters (^a-c) in the same column are significantly different at p<0.05 by Duncan’s multiple range test.