مجله پژوهشهای علوم و صنایع غذایی ایران (Nov 2024)
Evaluation of Persian Gum Effect on Microbial, Physicochemical and Sensory Properties of Brined Ultrafiltered Cheese during Storage
Abstract
Introduction Cheese is a term that encompasses a diverse group of fermented dairy products produced globally, available in a variety of flavors, textures, and shapes. It is rich in proteins, minerals, and vitamins, all contributing to its high nutritional value. Among these, brined ultrafiltered cheeses are soft cheeses that undergo their ripening process in brine. In recent times, this type of cheese has gained popularity, securing a significant consumer market in our country. Food hydrocolloids, comprising polysaccharides and proteins, are extensively utilized in the food, and biomedical industries. They function as thickening agents, forming gels with controlled functionality and specific physical properties. Additionally, they act as stabilizers in various dispersions and serve as carriers for bioactive compounds. Many hydrocolloids, such as whey proteins or dietary fibers, also possess health-promoting properties and can provide essential nutrients necessary for maintaining human biological activity. Beyond their nutritional benefits, food hydrocolloids find applications in advanced materials like food packaging, biomedical materials, biopolymers, polymer electrolytes, mineral nanoparticle synthesis, and organic pollutant removal. Natural hydrocolloids are typically non-toxic and environmentally friendly. They are made naturally from plants, animals, algae, or microorganisms. They are employed to enhance the physicochemical, structural, rheological, and sensory properties of dairy products. Persian gum, derived from the almond tree (Amygdalus scoparia Spach), is one such natural hydrocolloid commonly used as an herbal remedy in Iran. It is commercially available in various colors, shapes, and sizes. Its low cost, availability, biodegradability, and capability to substitute stabilizers and emulsifiers have increased its utilization in the food and pharmaceutical industries. Materials and Methods After being received and initially cooled, raw cow milk underwent pasteurization and was stored for the ultrafiltration process. Persian gum (PG) was incrementally incorporated into a specific quantity of warm retentate and thoroughly blended. This mixture was then combined with the remaining retentate to produce retentates with PG concentrations of 0.03%, 0.05%, and 0.1%. These mixtures were then subjected to homogenization and pasteurization. Following these processes, the retentate was cooled to a temperature range of 35-40°C. It was then poured into containers for coagulation, to which microbial rennet and a starter culture comprising Lactobacillus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, and Streptococcus thermophilus were added. After roughly 6 hours, once the curd pH dropped to 5.1, a 12% brine solution was introduced into the container. Finally, the containers were sealed and placed in a 4°C cold storage for microbial, physicochemical, and sensory evaluations over a 90-day storage period. Statistical analysis was conducted using the Minitab software (version 16.2.0.0 for Windows, Minitab Inc., Coventry, United Kingdom) at a 95% confidence level. Results and Discussion Based on the obtained results, during the storage period, no microbial spoilage (including coliforms, molds, and yeasts) was observed in the control and gum-containing samples. The ash content (%), gumminess (N), chewiness (Nmm), adhesiveness (Ns), and fracturability (N) of the samples increased initially up to day 45 and then decreased. The acidity (% lactic acid) of the samples continuously increased during the storage period, while the amount of fat (%) of samples showed a decreasing trend. An increase in gum concentration led to a significant decrease (p≤0.05) in the acidity (167.22 to 123.11 %), gumminess (8.35 to 1.30 N) and chewiness (216.19 to 38.83 Nmm) of the samples, while the ash content (3.69 to 3.92 %) and cheese adhesiveness (0.66 to 0.80 Ns) increased significantly (p≤0.05). Regarding sensory properties, color and appearance, and aroma scores of the cheeses were not significantly affected by the storage time. The interaction effect of time and gum concentration did not create a significant difference in texture and flavor scores, while their single effects were significant (p≤0.05). Overall acceptance of the samples was only significantly affected by the gum concentration (p≤0.05), and the interaction effect of time and concentration did not significantly affect the overall acceptance score. Finally, the cheese containing 0.5% gum received the highest sensory score compared to other samples, while the cheese containing 0.1% gum received the lowest sensory score. Considering the positive effect of Persian gum on various cheese properties, especially texture improvement, its utilization in industrial cheese production, as well as investigating its combined effects with other hydrocolloids, is recommended.
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