Zhao Pei, Zhang Shan, Xue Lu, Niu Tianjiao, Jiang Fan, Xiao Ran, Wu Zijian
Tianjin Key Laboratory of Food Biotechnology, College of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin 300134, China.
Tianjin Key Laboratory of Food Biotechnology, College of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin 300134, China.
Int J Biol Macromol. 2025 Aug;319(Pt 1):145324. doi: 10.1016/j.ijbiomac.2025.145324. Epub 2025 Jun 16.
As an emerging non-thermal processing technology, Ultra-high-pressure jet (UHPJ) processing has the effect of homogenizing and sterilizing materials concurrently. The UHPJ-treated skimmed milk was employed in this study to reveal the impact of pressure as the primary factor on protein structure and physicochemical properties. The results showed that with the increase of jet pressure, whey protein's endogenous fluorescence intensity increases, and casein's exogenous fluorescence intensity increases. The structure of casein tends to be loose, in contrast to the aggregation tendency of whey protein. After pressure treatment at 100-200 MPa, the thiol content peaked at 0.11 μmol/g. The content of α-helix increased to 17 %. The emulsifying stability of skim milk improved to 18.48 m/g, and its foaming expansion index and foaming stability index attained values of 27.65 % and 24.9 %, respectively. The digestion rate of milk proteins processed at 200 MPa was the highest in the gastric digestion stage and relatively high in the intestinal digestion stage. At 250 and 300 MPa, the SDS - PAGE electrophoresis results showed that the loose binding of casein and 18 kDa β-Lactoglobulin under high pressure was separated. The instantaneous decompression characteristic of UHPJ tends to destabilize the emulsion system by disrupting the formed interfacial layer, making the 250 and 300 MPa pressure range unfavorable for emulsion stabilization. This study will provide a scientific basis for applying UHPJ in the dairy industry.
作为一种新兴的非热加工技术，超高压射流（UHPJ）加工具有同时使物料均质化和杀菌的效果。本研究采用经超高压射流处理的脱脂乳，以揭示压力作为主要因素对蛋白质结构和理化性质的影响。结果表明，随着射流压力的增加，乳清蛋白的内源荧光强度增加，酪蛋白的外源荧光强度增加。与乳清蛋白的聚集趋势相反，酪蛋白的结构趋于松散。在100 - 200兆帕的压力处理后，巯基含量达到峰值0.11微摩尔/克。α-螺旋含量增加到17%。脱脂乳的乳化稳定性提高到18.48米/克，其发泡膨胀指数和发泡稳定性指数分别达到27.65%和24.9%。在200兆帕压力下处理的乳蛋白在胃消化阶段的消化率最高，在肠道消化阶段相对较高。在250和300兆帕时，SDS - PAGE电泳结果表明，高压下酪蛋白与18 kDaβ-乳球蛋白的松散结合被分离。超高压射流的瞬时减压特性倾向于通过破坏形成的界面层使乳液体系不稳定，使得250和300兆帕的压力范围不利于乳液稳定。本研究将为超高压射流在乳制品工业中的应用提供科学依据。
