彬
(2023-04-30 23:36):
#paper Fractionation of κ-casein from caprine micellar caseins using differential precipitation. https://doi.org/10.1016/j.idairyj.2023.105677. 江南大学食品科学与技术国家重点实验室等的Luo Guixin, Liu Xiaoming, Liu Dasong*, Zhou Peng等系统研究从山羊乳胶束酪蛋白浓缩物（micellar casein concentrate，MCC）中差异沉淀获得κ-酪蛋白的主要步骤中潜在关键加工条件的影响，还研究了酪蛋白浓度对κ-酪蛋白分馏的影响，旨在提高扩大条件下的加工能力。使用差异沉淀法对κ-酪蛋白进行分馏是基于单个酪蛋白在碱性pH值条件下对过量添加Ca的不同亲和力，然后进行中和，以促进αs-酪蛋白和β-酪蛋白的选择性沉淀。为提高从山羊乳MCC中分离的κ-酪蛋白产量和纯度，对每个主要步骤中的主要加工变量条件依次进行优化，得到最佳条件为：在pH 11.0条件下，使用匀浆再水合MCC（含3%酪蛋白），然后解离胶束；添加45 mmol/L Ca在25 ℃条件下络合酪蛋白60 min，然后使用2 mol/L乙酸在pH 7.0、25 ℃条件下再次沉淀β-/αs-酪蛋白60 min；使用2 个分馏循环，在第2个循环中添加50 mmol/L Ca，然后在pH 3.8、50 ℃条件下沉淀κ-酪蛋白。为提高扩大条件下的加工能力，将酪蛋白浓度提高4%~7%，同时添加60 mmol/L Ca，可获得与最佳条件下相当的κ-酪蛋白产量和纯度。在酪蛋白含量为4%时，MCC分散体中κ-酪蛋白的最大产量和纯度分别为84.6%和84.4%。
Fractionation of κ-casein from caprine micellar caseins using differential precipitation
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Abstract:
The effects of potentially important processing conditions at each step of differential precipitation on the yield and purity of κ-casein fractionated from caprine micellar casein concentrate (MCC) were investigated. The optimal conditions were: rehydrating (3% casein) MCC using homogenisation followed by dissociating micelles at pH 11.0; complexing caseins using 45 mm added Ca at 25 °C for 60 min, followed by precipitating β-/αS-caseins using 2 m acetic acid at pH 7.0 again at 25 °C for 60 min. Two fractionation cycles were used with 50 mm added Ca for the second cycle, followed by precipitating κ-casein at pH 3.8 and 50 °C. To increase processing capacity for scale-up, increased casein concentrations of 4–7% along with 60 mm added Ca resulted in comparable yields and purity of the κ-casein. Maximum yield and purity of 84.6% and 84.4%, respectively, were achieved for κ-casein from the MCC dispersions at 4% casein.
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