Quarg Cheese: The Impact of Fat Content Change on its Microstructure, Characterization, Rheology, and Textural Properties

This study aimed to investigate the impact of different levels of fat content on the microstructure, rheology, and textural characteristics of Quarg cheese. Quarg is a soft unripened cheese variety made by the addition of mesophilic starter cultures (Lactococcus lactis subsp. lactis, Leuconostoc citrovorum) and a trace of rennet. The fat levels of cheese were; 6.0 ± 0.01 (QC1), 3.5 ± 0.03 (QC2), 1.5 ± 0.03 (QC3), and 0.5 ± 0.02 (QC4). Statistically significant changes (p< 0.05) were observed in the values of textural parameters. Furthermore, rheological investigations indicated a positive correlation between the reduction in fat percentages and an increase in the hardness of the cheese. The characterization of the sample was conducted using Fourier Transform Infrared (FTIR) and Ultraviolet-Visible (UV-Vis) spectrophotometric techniques. The microstructure of quarg cheese was analyzed using fluorescence microscopy and helped depict the distribution of fat and protein in the cheese matrix. Sensorial properties were superior in cheese samples with higher fat percentages as a virtue of fat content.