Effect of guar gum as a stabilizer on the physicochemical, textural, and sensory characteristics of liquid Kashk (a traditional dairy product)

• Phase separation is the main quality defect of industrial liquid kashk (ILK). • Guar gum addition improves the water-holding capacity of ILK. • Lower syneresis was observed upon guar gum addition during storage of ILK. • Guar gum improves texture by increasing the hardness and cohesiveness of ILK. • Guar gum enhances sensory attributes and overall acceptability of ILK. Industrial liquid kashk (ILK) is a pasteurized dairy product made from bovine milk yogurt and dried kashk, a traditional Iranian dairy product. The study investigated the effects of guar gum concentration (0.1, 0.2, and 0.3% w/w) on the physicochemical, microbiological, and sensory properties of ILK during 60 days of cold storage. The concentration of guar gum significantly affected the pH, acidity, and color attributes of ILK samples ( P < 0.05). All formulations met microbiological safety standards, exhibiting no growth of coliform bacteria or yeast. Notably, ILK samples with higher concentrations of guar gum (G-0.2 and G-0.3) exhibited significantly lower syneresis rates (2.56% and 6.07%, respectively) compared to the control (36.39%) after 60 days of storage. Additionally, increasing the guar gum concentration improved the water-holding capacity, achieving maximum values of 100% for the G-0.3 formulation, compared to 85.8% in the control sample. On day 1, adding guar gum significantly increased the hardness of the samples from 113.3 g in the control sample to 151-224 g, and enhanced cohesiveness from 0.44 to a range of 0.52-0.74. Scanning electron microscopy revealed that guar gum promoted a more compact microstructure and reduced pore size in ILK. Sensory evaluations revealed that all formulations maintained acceptable color and appearance throughout storage, with no adverse effects on taste or odor attributable to adding guar gum. These findings highlight the crucial role of guar gum in developing high-quality dairy products with improved sensory attributes and enhanced storage stability.