Advanced Food Systems Research Unit, Institute of Sustainable Industries and Liveable Cities and College of Health and Biomedicine, Victoria University, Werribee Campus, Victoria 3030, Australia.
Faculty of Biotechnical Sciences, University "St. Kliment Ohridski," Bitola 7000, Macedonia.
J Dairy Sci. 2021 Mar;104(3):2834-2842. doi: 10.3168/jds.2020-19542. Epub 2021 Jan 15.
Heating, pressurization, and shearing can modify native milk proteins. The effects of pressurized heating (0.5 vs. 10 MPa at 75 or 95°C) with shearing (1,000 s) on proteins of raw bovine skim milk (SM, ∼9% total solids) and concentrated raw skim milk (CSM, ∼22% total solids) was investigated. The effects of evaporative concentration at 55°C and pressurized shearing (10 MPa, 1,000 s) at 20°C were also examined. Evaporative concentration of SM resulted in destabilization of casein micelles and dissociation of α- and β-casein, rendering CSM prone to further reactions. Treatment at 10 MPa and 1,000 s at 20°C caused substantial dissociation of α- and β-casein in SM and CSM, with some dissociated caseins forming shear-induced soluble aggregates in CSM. The pressure applied at 10 MPa induced compression of the micelles and their dissociation in SM and CSM at 75 or 95°C, resulting in reduction of the micelle size. However, 10 MPa did not alter the mineral balance or whey proteins denaturation largely, except by reduction of some β-sheets and α-helices, due to heat-induced conformational changes at 75 and 95°C.
加热、加压和剪切会改变天然乳蛋白。研究了在剪切（1000 秒，1000 秒）下加压加热（0.5 与 10 MPa，75 或 95°C）对生牛脱脂乳（SM，约 9%总固体）和浓缩生脱脂乳（CSM，约 22%总固体）中蛋白质的影响。还研究了在 55°C 蒸发浓缩和在 20°C 下加压剪切（10 MPa，1000 秒）的影响。SM 的蒸发浓缩导致酪蛋白胶束的不稳定性和 α-和 β-酪蛋白的解离，使 CSM 更容易发生进一步的反应。在 20°C 下处理 10 MPa 和 1000 秒会导致 SM 和 CSM 中 α-和 β-酪蛋白的大量解离，一些解离的酪蛋白在 CSM 中形成剪切诱导的可溶性聚集体。在 75 或 95°C 下，10 MPa 的压力会导致 SM 和 CSM 中胶束的压缩和解离，从而减小胶束的大小。然而，10 MPa 不会显著改变矿物质平衡或乳清蛋白的变性，除了由于 75 和 95°C 下热诱导的构象变化，导致一些β-折叠和α-螺旋的减少。
