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Updated: Jun 30, 2026

Mass Spectrometric Approaches to Study Protein Structure and Interactions in Lyophilized Powders
Published on: April 14, 2015
The effect of pH on the microstructure, rheological and functional properties of halloumi-type cheese:
Xiaoxuan Zhao1, Yumeng Zhang1, Gaoyang Cui1
1Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
Abstract:
This study investigated the impact of pH on the microstructure and functional properties of Halloumi-type cheese produced from cow milk. The optimal pH for non-melting during frying and ideal oil release was above 6.41 or below 4.69. Lowering pH to 5.33 reduced rennet coagulation time (RCT) to 4.5 min. Further pH decrease reduced calcium (Ca) content by 89.4 % but increased water-holding capacity (WHC) by 16.7 %. As pH dropped from 6.53 to 5.33, colloidal calcium phosphate (CCP) dissolved, weakening the protein network via electrostatic repulsion, which decreased storage modulus, increased melt flow, and enhanced free oil release. Below pH 4.69, hydrophobic interactions and hydrogen bonding strengthened, increasing gel strength and reducing melt flow and oil release. Microstructure showed larger pores and fat aggregation at low pH, and FTIR confirmed altered protein interactions. Thus, pH critically regulates meltability by modifying calcium content and protein interactions.
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