Abstract:

Objective: To compare the difference in pork quality between Meishan and crossbred pigs, and to examine the
possible factors contributing to the water holding capacity of two breeds. Methods: Six Meishan purebred pigs and six
crossbred pigs were slaughtered and their left longissimus dorsi muscles were used as samples. Water distribution was
measured using lower field-nuclear magnetic resonance (LF-NMR) and calpain activity was determined using casein
zymography, purge loss at day 1, 3, and 7 sand cooking loss at day 1 postmortem were measured. Results: Compared with
crossbred pork, Meishan pork presented lower L* values and greater a* values (P < 0.05). Purge loss of both Meishan and
crossbred pork increased gradually during 1, 3 and 7 d of postmortem storage. Meishan pork presented less purge loss
compared to crossbred pork at day 1 and 3 (P < 0.05), and no significant difference was found between two breeds at day 7.
Muscles from Meishan pigs exhibited less cooking loss (P < 0.05) at day 1, indicating that Meishan pork has a better water
holding capacity compared to crossbred pork. Additionally, samples from Meishan pigs showed significantly higher pH
values at 45 min postmortem compared to crossbred samples (P < 0.05). LF-NMR T2 relaxation data showed that Meishan
pork had significantly bigger area of T2b and smaller area of T22 (P < 0.05). Finally, Meishan pork indicated significantly
greater μ-calpain activity at day 1 postmortem (P < 0.05) but no significant difference at day 3 and 7 was found between the
two breeds. Conclusions: Calpain activity has no significant impacts on water holding capacity of the two breeds, whereas
water distribution and 45 min pH could explain the higher water holding capacity of Meishan pork.

Key words: Meishan pig, meat color, water holding capacity, pH, lower field-nuclear magnetic resonance (LF-NMR), calpain activity