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| Quality Changes of Ningxia Beef Cattle By-products during Frozen Storage |
| WANG Xiaojing, WANG Jinsong, XU Feiran, ZHAO Zidan, FU Qihua |
| 1. Ningxia Institute of Quality Standards and Testing Technology for Agricultural Product, Yinchuan 750002, China; 2. School of Food and Biological Engineering, Hefei University of Technology, Hefei 230002, China |
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Abstract The changes in the total volatile basic nitrogen (TVB-N) content, malondialdehyde (MDA) content, water content, protein content, cooking loss rate, total bacterial count, pH value, and color of by-products (heart, liver, tripe, and intestine) of Ningxia beef cattle after different freezing periods (at ?18 ℃ for 1, 30, 60, 90, and 180 days) were analyzed. The results showed that the pH value of bovine liver changed the fastest in the first 30 days. The brightness (L*) and yellowness values (b*) of bovine heart, liver, tripe, and intestine showed a significant upward trend (P < 0.05), whereas the reverse trend was observed for the redness value (a*) of bovine heart and liver (P < 0.05). After 180 days of freezing, the cooking loss rate and water loss of beef liver were the greatest, and so were the protein loss of bovine intestine, as well as the increase in the MDA and TVB-N contents of bovine heart. On the 90th day, for all bovine by-products, the TVB-N content approached the national standard limit and the total bacterial count exceeded 1 × 106 CFU/g, reaching the cutoff for being considered spoiled. Principal component analysis (PCA) showed significant differences in the quality attributes of bovine heart, liver, tripe, and intestine at different storage periods. Correlation analysis showed a significant negative correlation between the contents of MDA and TVB-N and protein content for all four by-products (P < 0.05 or P < 0.01). For bovine heart, there was a significant negative correlation between water content and L* and b* (P < 0.01) and MDA content was significantly positively correlated with TVB-N content, L* and b* (P < 0.01), but significantly negatively correlated with a* (P < 0.01). In summary, for all bovine by-products, quality deterioration and significant nutrient loss occurred during frozen storage, and among these, bovine liver showed the largest decrease in water-holding capacity, bovine hear the greatest degree of lipid oxidation, and bovine intestine the greatest protein loss. These by-products can be frozen at ?18 ℃ for up to 60 days.
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2025, Vol. 39 
