Table 3. Physico-chemical traits and residual nitrite of cooked pork sausages containing two different percentages of purple sweet potato combined with nitrite during storage

Items	Treatments¹⁾	Storage (days)
Items	Treatments¹⁾	0	5	10	15	20
pH	CON	6.06±0.01^A^d	6.07 ± 0.00^D^d	6.16 ± 0.02^A^b	6.26 ± 0.02^A^a	6.10 ± 0.01^C^c
	CON1	6.03 ± 0.01^AB^d	6.12 ± 0.01^B^b	6.16 ± 0.01^A^a	6.12 ± 0.00^D^b	6.10 ± 0.01^C^c
	PP1	6.01 ± 0.01^B^c	6.05 ± 0.01^E^b	6.08 ± 0.01^C^a	6.08 ± 0.01^E^a	6.08 ± 0.01^D^a
	PP2	6.01 ± 0.01^B^c	6.04 ± 0.00^E^c	6.09 ± 0.01^C^a	6.09 ± 0.01^D^a	6.09 ± 0.01^D^a
	SP1	6.04 ± 0.02^AB^c	6.17 ± 0.01^A^a	6.11 ± 0.01^B^b	6.11 ± 0.01^D^b	6.18 ± 0.02^A^a
	SP2	6.05 ± 0.04^A^c	6.10 ± 0.01^C^b	6.15 ± 0.00^A^a	6.14 ± 0.00^C^a	6.12 ± 0.02^B^ab
WHC (%)	CON	79.04 ± 2.39^A^a	68.84 ± 0.05^D^b	70.95 ± 2.10^B^b	52.87 ± 0.62^C^c	71.68 ± 1.52^B
	CON1	74.99 ± 0.44^BC^a	70.48 ± 0.96^CD^b	71.04 ± 2.20^B^b	61.74 ± 1.59^A^c	72.58 ± 0.54^A^b
	PP1	68.90 ± 2.34^D^b	72.17 ± 0.98^BC^a	74.48 ± 2.36^AB^a	56.24 ± 1.34^B^c	72.52 ± 0.42^A
	PP2	72.32 ± 0.88^C^b	73.67 ± 0.71^AB^ab	75.78 ± 1.79^A^a	57.17 ± 2.06^B^c	73.66 ± 1.00^A^b
	SP1	73.80 ± 0.76^BC^a	70.55 ± 1.40^CD^b	71.82 ± 1.74^B^ab	58.77 ± 1.15^B^c	71.78 ± 0.61^A^b
	SP2	75.75 ± 0.70^B^a	75.43 ± 1.40^A^a	73.95 ± 0.52^AB^ab	58.24 ± 1.60^B^c	72.16 ± 0.45^B
Shear force (kg/cm²)	CON	1.34 ± 0.04^bc	1.27 ± 0.14^C	1.25 ± 0.02^D^c	1.47 ± 0.04^C^ab	1.50 ± 0.10^C^a
	CON1	1.36 ± 0.12^C	1.36 ± 0.04^C	1.64 ± 0.04^A^b	1.43 ± 0.05^C^c	1.91 ± 0.08^A^a
	PP1	1.47 ± 0.06^bc	1.40 ± 0.05^C	1.40 ± 0.06^C^c	1.54 ± 0.11^C^b	1.85 ± 0.05^AB^a
	PP2	1.38 ± 0.06^C	1.39 ± 0.06^C	1.55 ± 0.03^B^b	1.58 ± 0.02^B^ab	1.67 ± 0.08^BC^a
	SP1	1.44 ± 0.09^B	1.38 ± 0.15^B	1.43 ± 0.02^C^b	1.53 ± 0.07^BC^b	1.96 ± 0.05^A^a
	SP2	1.40 ± 0.06^B	1.38 ± 0.07^B	1.37 ± 0.03^C^b	1.73 ± 0.03^A^a	1.84 ± 0.16^A^a
VBN (mg%)	CON	4.20 ± 0.28^A^a	2.99 ± 0.16^C	3.17 ± 0.16^AB^bc	3.45 ± 0.16^B	3.36 ± 0.28^A^bc
	CON1	3.73 ± 0.16^AB^a	2.89 ± 0.16^B	3.08 ± 0.00^B^b	3.08 ± 0.28^B	2.99 ± 0.16^AB^b
	PP1	3.17 ± 0.16^B^ab	2.71 ± 0.16^C	3.45 ± 0.16^A^a	3.36 ± 0.28^A	2.89 ± 0.32^B^bc
	PP2	3.36 ± 0.28^B^a	2.80 ± 0.28^B	2.61 ± 0.16^C^b	3.08 ± 0.28^A^b	2.89 ± 0.16^B^b
	SP1	4.11 ± 0.81^A^a	2.99 ± 0.32^B	2.99 ± 0.16^B^b	3.17 ± 0.16^B	3.08 ± 0.00^AB^b
	SP2	3.27 ± 0.16^B^ab	2.89 ± 0.16^B	3.08 ± 0.28^B^ab	3.36 ± 0.28^A	3.17 ± 0.16^AB^ab
Residual nitrite (ppm)	CON	13.35 ± 0.62^A	ND	ND	ND	11.64 ± 1.40^A
	CON1	4.31 ± 1.16^B	ND	ND	ND	3.72 ± 0.63^D
	PP1	6.77 ± 2.59^B	ND	ND	ND	3.54 ± 0.77^D
	PP2	5.62 ± 1.34^B	ND	ND	ND	6.91 ± 0.25^C
	SP1	12.85 ± 0.88^A^a	ND	ND	ND	9.83 ± 0.17^B^b
	SP2	15.37 ± 0.42^A^a	ND	ND	ND	10.23 ± 0.20^B^b

Data represent mean ± SD.
Treatments: CON (control), 0.014% sodium nitrite; CON1 (control1), no sodium nitrite and purple-fleshed sweet potato powder combination; PP1, no sodium nitrite and 0.5% purple-fleshed sweet potato powder; PP2, no sodium nitrite and 1% purple-fleshed sweet potato powder; SP1, 0.011% sodium nitrite and 0.5% purple-fleshed sweet potato powder combination; SP2, 0.011% sodium nitrite and 1% purple-fleshed sweet potato powder combination.
Means in the same column within the same aging period with different letters are significantly different (p < 0.05).
Means in the same row within the same aging condition with different letters are significantly different (p < 0.05).