The Effect of Nanoliposomes of Achillea millefolium Essential Oil on the Shelf Life of Fresh Beef at Refrigerated Storage

Abstract

Nanoencapsulation of essential oils (EOs) improves their solubility, stability, and bioavailability. This research aimed to prepare nanoliposomes containing 1% and 2% yarrow (Achillea millefolium) EO and their effect on the shelf life of fresh beef at refrigerated storage. Nanoliposome properties, including encapsulation efficiency, particle size, zeta potential, morphology, Fourier transform infrared (FTIR) spectroscopy, and thermal properties, were evaluated. The nanoliposomes were characterized by an appropriate nanosize scale (91.3–139 nm) and a negative charge (−27.35 mV to −22.64 mV) that successfully encapsulated the EO with high efficiency (> 86%). Scanning electron microscopy (SEM) showed a homogeneous structure in which the EO was well dispersed in the nanoliposome matrix. The FTIR spectrum indicated the successful incorporation of the EO into the nanoliposomes without changing their chemical structure. Differential scanning calorimetry (DSC) findings confirmed that the glass transition (T_g) and melting (T_m) temperatures increased about 2°C with nanoliposomes, resulting in an improvement in thermal stability. The nanoliposomes containing 2% yarrow EO (NLP-2% EO) with the smallest particle size and highest encapsulation efficiency, zeta potential, antioxidant properties, and thermal stability were selected as the best treatment and used to preserve fresh beef for 10 days. During the meat storage, pH values, total volatile nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), and total mesophilic and psychrophilic bacteria increased significantly (p < 0.05), indicating meat spoilage. Regarding chemical and microbial indices, the control treatment (C) and the treatment containing free EO were acceptable for less than 5 days and 5–10 days, respectively, while the incorporation of EO into nanoliposomes (NLP-EO) extended the shelf life of fresh beef up to 10 days at 4°C. Therefore, the encapsulated yarrow EO in nanoliposomes was suggested for beef preservation.