با همکاری انجمن علوم و صنایع غذایی ایران
نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم و صنایع غذایی، واحد تهران شمال، دانشگاه آزاد اسلامی، تهران، ایران
2 گروه علوم و صنایع غذایی، واحد ورامین-پیشوا، دانشگاه آزاد اسلامی، تهران، ایران
کلیدواژه‌ها
عنوان مقاله English
نویسندگان English
Introduction: Garlic essential oil (GEO), owing to its bioactive sulfur compounds, exhibits strong antimicrobial activity; however, its high volatility and environmental sensitivity limit direct application in foods. Microencapsulation offers an effective strategy to enhance stability and enable controlled release.
Aim: This study aimed to produce white brine cheese enriched with microencapsulated GEO and evaluate its microbiological, physicochemical, and sensory properties.
Material and method: GEO composition was determined by GC–MS, identifying diallyl disulfide and diallyl trisulfide as dominant sulfur compounds. GEO was microencapsulated via spray drying using maltodextrin and gum arabic as wall materials. Encapsulation was confirmed by FTIR, and microcapsule characteristics—including morphology, particle size distribution, polydispersity index (PDI), and zeta potential—were assessed. Particles exhibited spherical morphology, appropriate size distribution, low PDI, and favorable zeta potential.White brined cheese was produced traditionally. Treatments included control (no GEO), free GEO (FG), and microencapsulated GEO (MG) at 0.5%, 1%, and 1.5%. Samples were evaluated on days 0, 30, and 60 for microbiological, physicochemical, and sensory attributes (5-point hedonic test). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of free and microencapsulated GEO were determined against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella Typhimurium.
Results and Discussion: Treatment, time, and treatment×time interaction significantly affected L. monocytogenes counts (p≤0.05). The 0.5% MG treatment reduced pathogenic bacteria by 1.6 log CFU/g versus control on day 60, without adverse sensory effects. The results of zeta potential measurements showed that the average zeta potential of the microcapsules containing garlic essential oil was 34.20±1.5 mV. This negative and relatively high value indicates the presence of a significant negative surface charge on the microcapsule particles and indicates the favorable electrostatic stability of the colloidal system. DLS results showed that the average hydrodynamic diameter of the garlic essential oil microcapsules is in the nanometer range. Such a size is usually associated with the formation of more stable colloidal systems, since Brownian motion can overcome sedimentation. In addition, the low PDI value indicates a narrow particle size distribution and good uniformity of the system. SEM images showed that the microcapsules were mainly spherical to quasi-spherical in shape and their surface was relatively smooth and uniform. Based on SEM image analysis with ImageJ software, the average diameter of the produced microcapsules was 2.64±13.79 μm. This particle size distribution and low standard deviation indicate proper uniformity of the microcapsule process and optimal control over production conditions. Morphological results confirm that the garlic essential oil microcapsule process has led to the production of microcapsules with a regular structure, intact walls, and appropriate size distribution.Physicochemically, 0.5% MG better controlled pH and titratable acidity changes; fat content was unaffected by treatments. The results of MIC and MBC tests showed that Gram-positive bacteria are more sensitive to garlic essential oil than Gram-negative bacteria, and this effect is enhanced by increasing the concentration. The results of two-way ANOVA showed that the effect of treatment, storage time, and their interaction on the moisture content of cheese was significant (P<0.05). In general, the moisture content of cheese decreased during 60 days of storage, which could be due to water evaporation, syneresis of the casein matrix, and rearrangement of the protein structure during ripening. Sensory evaluation showed 0.5% MG achieved the highest scores for flavor, aroma, texture, color, and overall acceptability (4.4/5) throughout storage. Thus, 0.5% microencapsulated GEO effectively enhances microbial safety and preserves sensory quality of white brine cheese.
Conclusion: The results of this study showed that garlic essential oil, especially in microencapsulated form, can be used as a natural and effective preservative to improve microbial safety and increase the shelf life of brine white cheese, without causing a significant decrease in sensory acceptance. Compared with the free essential oil, the microencapsulated form showed a more stable and effective antimicrobial effect against the indicated microorganisms and pathogens, especially Listeria monocytogenes and Staphylococcus aureu. Also, the gradual release and reduced evaporation of the active compounds in this system played an important role in maintaining the microbial and sensory quality of the product.
Funding Sources:This research did not receive any specific funding from funding organizations in the public, commercial, or non-profit sectors.
Acknowledgement: We would like to express our gratitude for the cooperation of the research laboratories of the Food and Drug Administration of Markazi Province (Arak).
کلیدواژه‌ها English
