McMartin S, Godden S, Metzger L, Feirtag J, Bey R, Stabel J, Goyal S, Fetrow J, Wells S, Chester-Jones H
Department of Veterinary Population Medicine, University of Minnesota, St. Paul 55108, USA.
J Dairy Sci. 2006 Jun;89(6):2110-8. doi: 10.3168/jds.S0022-0302(06)72281-0.
The objective of this study was to identify the critical temperature, at or below which heat-treatment of bovine colostrum would produce no significant changes in viscosity, IgG concentration, or Ig activity. Results of preliminary work, using a Rapid Visco Analyzer (RVA) to heat 50-mL aliquots from 6 unique batches of bovine colostrum at 59, 60, 61, 62, and 63 degrees C, suggested that colostrum could be heated to 60 degrees C for up to 120 min without changing viscosity or IgG concentration. This finding was confirmed by heating 50-mL aliquots from 30 unique batches of colostrum in an RVA for 120 min at 60 and 63 degrees C. Heating colostrum to 63 degrees C resulted in an estimated 34% decrease in IgG concentration and 33% increase in viscosity. However, there was no difference in IgG concentration between preheat-treated (73.4 +/- 26.5 mg/mL) and post-heat-treated (74.5 +/- 24.3 mg/mL) samples after heating colostrum to 60 degrees C in an RVA for 120 min. Similarly, viscosity was unaffected after heating colostrum to 60 degrees C in an RVA for 120 min. High quality colostrum (> or =73.0 mg/mL) suffered greater losses of IgG and greater viscosity changes when heated to 63 degrees C than did moderate quality colostrum (<73.0 mg/mL). However, the effects of colostrum quality were minor if high quality colostrum was only heated to 60 degrees C. The results of a bovine viral diarrhea serum neutralization assay suggested that antibody activity was unchanged after heating colostrum to either 60 or 63 degrees C. However, these results were interpreted as being inconclusive due to a high proportion of missing results because of the congealing of many samples after heat treatment. The results of this study indicate that 50-mL volumes of bovine colostrum can be heat treated at 60 degrees C for up to 120 min in an RVA without affecting IgG concentration or viscosity.
本研究的目的是确定临界温度，在该温度及以下对牛初乳进行热处理不会导致其粘度、IgG浓度或Ig活性发生显著变化。初步研究结果表明，使用快速粘度分析仪（RVA）在59、60、61、62和63摄氏度下对6个不同批次的50毫升牛初乳样品进行加热，结果显示牛初乳可以在60摄氏度下加热长达120分钟而不改变其粘度或IgG浓度。在RVA中对30个不同批次的50毫升牛初乳样品在60和63摄氏度下加热120分钟，证实了这一发现。将牛初乳加热到63摄氏度导致IgG浓度估计降低34%，粘度增加33%。然而，在RVA中将牛初乳在60摄氏度下加热120分钟后，预热处理（73.4±26.5毫克/毫升）和热处理后（74.5±24.3毫克/毫升）的样品之间IgG浓度没有差异。同样，在RVA中将牛初乳在60摄氏度下加热120分钟后，粘度不受影响。与中等质量的牛初乳（<73.0毫克/毫升）相比，高质量的牛初乳（≥73.0毫克/毫升）在加热到63摄氏度时IgG损失更大，粘度变化也更大。然而，如果仅将高质量的牛初乳加热到60摄氏度，牛初乳质量的影响较小。牛病毒性腹泻血清中和试验结果表明，将牛初乳加热到60或63摄氏度后抗体活性未发生变化。然而，由于热处理后许多样品凝固导致大量结果缺失，这些结果被认为是不确定的。本研究结果表明，50毫升体积的牛初乳可以在RVA中于60摄氏度下加热长达120分钟而不影响IgG浓度或粘度。
