Table 3. Influence of naturally converted nitrite and ultrasound marination on myofibril fragmentation index (MFI), protein solubility, and shear force of pork loin

Traits	NC	PC	PA	PA+A	PA+U	PA+AU
MFI	116.11±1.28	110.45±1.03	112.27±1.80	113.20±5.13	111.62±1.40	111.33±1.31
Total protein solubility (mg/mL)	9.46±0.04^c	9.51±0.05^c	9.83±0.05^b	9.74±0.09^b	10.04±0.00^a	10.12±0.02^a
Myofibrillar protein solubility (mg/mL)	7.25±0.06^d	7.35±0.05^cd	7.55±0.05^b	7.49±0.11^bc	7.81±0.02^a	7.87±0.01^a
Sarcoplasmic protein solubility (mg/mL)	2.21±0.03^ab	2.16±0.01^b	2.28±0.01^a	2.24±0.03^a	2.23±0.02^ab	2.25±0.03^a
Shear force (N)	44.43±1.71^d	57.40±2.67^a	51.25±2.55^bc	56.26±0.86^ab	49.33±1.90^cd	51.94±0.76^bc

Values are presented as mean±SE (n≥3).
Different letters within the same row indicate significant differences between treatments (p<0.05).
NC, cured without sodium nitrite; PC, cured with sodium nitrite (180 ppm); PA, cured with a pre-converted Angelica keiskei extract (180 ppm of nitrite); PA+A, cured with a pre-converted A. keiskei extract (180 ppm of nitrite) and ascorbic acid; PA+U, cured with a pre-converted A. keiskei extract (180 ppm of nitrite) and marinated using ultrasound; PA+AU, cured with a pre-converted A. keiskei extract (180 ppm of nitrite) and ascorbic acid, and marinated using ultrasound.