Table 4.

Effect of photoperiod on instrumental color attributes (CIE L∗ [lightness], CIE a∗ [redness], CIE b∗ [yellowness], hue angle [discoloration], and chroma [color intensity]) and thiol content of ground broiler meat patties during display storage.

Treatment	Instrumental color attribute					Thiol content1
	CIE L∗	CIE a∗	CIE b∗	Hue angle	Chroma
Photoperiod effect (P)
20L:4D	56.5	8.8	11.0a	51.3	14.1a	22.6
18L:6D	55.4	9.0	10.8a	50.1	14.1a	23.0
16L:8D	54.6	9.1	10.2b	47.9	13.7a	22.7
12L:12D	55.1	8.3	9.8b	49.6	12.9b	22.2
SEM	0.8	0.4	0.3	1.0	0.4	0.6
Display period effect (D)
0 D	55.5	10.4x	12.8x	50.9	16.6x	24.7x
1 D	55.6	8.8y	10.4y	49.6	13.6y	-
2 D	55.1	8.6y,z	9.6y	48.3	12.9y	22.6x,y
3 D	55.2	8.2z	9.6y	49.3	12.7y	-
4 D	55.5	8.1z	9.8y	50.7	12.7y	20.5y
SEM	0.8	0.4	0.5	1.1	0.5	0.7
Significance of P-value
P	0.053	0.128	0.009	0.150	0.006	0.490
D	0.869	<0.001	0.003	0.399	<0.001	0.023
P × D	0.889	0.102	0.867	0.801	0.466	0.437

^a,bLeast square means lacking a common superscript within a column are different due to photoperiod effect (P < 0.05).

^x-zLeast square means lacking a common superscript within a column are different due to display period effect (P < 0.05).

¹Thiol content is expressed as nM thiol groups per mg protein.