Spray-dried microcapsules of Zygophyllum gaetulum extracts: Characterization and efficacy in extending minced meat shelf life

Microencapsulation technique is a practical method used to establish a protective barrier around sensitive bioactive substances, enhancing their stability, and offering controlled release in food systems. The present study investigates the encapsulation of freeze-dried and oven-dried ethanolic extracts (FDEE and ODEE, respectively) of Zygophyllum gaetulum , which exhibited total phenolic contents of 220.66 and 151.04 mg GAE/g, respectively, by spray drying using maltodextrin and gum arabic, in a 70:30 (w/w) ratio, as coating materials. The encapsulation efficiency of resulted microcapsules reached 82.76% and 79.88% for FDEE and ODEE, respectively, at an optimal 5% extract loading. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) confirmed the physical interactions and protective role of the encapsulating matrix , with encapsulation improving thermal stability by increasing T max from 285–290°C in free extracts to 310–320°C in loaded microcapsules. Encapsulated extracts also exhibited strong antioxidant activity, with EFDEE reaching 98% DPPH radical inhibition, and showed minimal release under gastric conditions followed by over 80% release during simulated intestinal digestion. The effects of the addition of encapsulated freeze-dried and oven-dried ethanolic extracts (EFDEE and EODEE, respectively), free extracts, and empty microcapsules on physicochemical, color, oxidative, and microbial properties of minced meat were evaluated against a negative control. EFDEE and EODEE significantly (p<0.05) improved physicochemical parameters and oxidative and microbial stability compared to free extracts and control groups. Notably, EFDEE was the most effective in reducing the oxidation by 50% and limiting microbial growth, underscoring the potential of microencapsulation combined with freeze drying as a natural strategy to extend the shelf life of meat products.