Short communication: Influence of intramuscular injection of vitamin B12 in early-lactation dairy cows on Mozzarella cheese quality and vitamin B12 stability
2020
Xu, N.N. | Yang, D.T. | Zhang, B.X. | Liu, J.X. | Ye, J.A. | Ren, D.X.
The current study explored the effect of intramuscular injection of vitamin B₁₂ (VB₁₂) in early-lactation dairy cows on subsequent low-moisture part-skim Mozzarella cheese quality and VB₁₂ levels during cheese processing and storage. Twenty-four peripartum dairy cows were blocked based on parity and milk yield and randomly assigned into 2 treatments: basal diet (CON) and basal diet with an intramuscular injection of 10 mg of VB₁₂ per cow per week (VB₁₂). Raw milk was collected to determine VB₁₂ content and then used to make low-moisture part-skim Mozzarella cheese 8 wk after injection. The VB₁₂ content of raw milk and cheese was determined using ultra-performance liquid chromatography coupled with tandem mass spectrometry. We found that VB₁₂ content was significantly increased in milk (15.43 vs. 3.30 ng/mL) and fresh cheese (3.72 ng/g vs. undetectable) from the VB₁₂ group compared with the CON group. However, approximately 70% of VB₁₂ was lost in the whey during cheese making, and no VB₁₂ was detectable in either cheese treatment after 8 wk of storage. Furthermore, no significant differences were observed in fat and protein contents in the cheese between the 2 groups. For cheese color, the b* value increased and the a* value decreased slightly in fresh VB₁₂ cheese. Functional properties of stretchability, flowability, and meltability of VB₁₂ cheese were initially comparable to that of CON cheese, but higher flowability and meltability was observed in VB₁₂ cheese after 8 wk of storage. In summary, intramuscular injection of VB₁₂ in early-lactation dairy cows increases the content of VB₁₂ in milk and fresh cheese with no adverse effect on cheese quality, but substantial VB₁₂ is lost during cheesemaking and declines rapidly during storage.
显示更多 [+] 显示较少 [-]