ABSTRACT
This study was carried out to evaluate the effect of liquid smoke (LS) produced from beech sawdust and thyme essential oil (TEO) as natural antioxidants in chicken and turkey meatballs during frozen storage. The LS and TEO were added to chicken and turkey meatballs at levels of 1% and 0.1%, respectively, and storage at -18 ± 1°C for 6 months. pH value, water holding capacity (WHC), total volatile nitrogen (TVN), thiobarbituricacid (TBA) value, peroxide values (PV), total phenolic compounds (TPC) and antioxidant activity (DPPH %) were determined. The results demonstrated that the addition of LS or TEO had a positive effect on storage stability and a little change in the physical properties, quality attributes, and significantly (p≤0.05) increased the values of total phenolic compounds and antioxidant activity of chicken and turkey meatballs during frozen storage compared to the control sample. The data revealed that the application of liquid smoke had decreased the value of TBA, TVN, and PV as well as increased shelf life and could be useful to achieve high stability of activity of chicken and turkey meatballs during storage and was better accepted compared to TEO and control.
ABSTRACT
Suspensions of poly ε-caprolactone (PCL) nanoparticles loaded with thyme essential oil were prepared as a natural antioxidant in mayonnaise. Mean particle size was 204.9 ± 2.7 and 240.0 ± 5.5 nm respectively for nanoparticles prepared with PCL alone (NP-C) and for those loaded with thyme essential oil (NP-T). The polydispersity index indicated a homogeneous distribution of all particles, with no significant difference between NP-C and NP-T samples. The nanoparticles showed a large negative charge evidenced by zeta potential rates, indicating high physical stability. The use of PCL as a polymer provided high encapsulation efficiency for thyme essential oil (91.15 ± 2.12 %). DPPH (2,2-diphenyl-1-picrylhydrazyl) method determined IC50 rates were 476.4 ± 33.6 and 483.5 ± 20.4 µg mL-1respectively for unencapsulated oil and for NP-T, evidencing pronounced antioxidant activity. NP-C, NP-T and synthetic antioxidant butylhydroxytoluene (BHT) were applied to samples of mayonnaise and their oxidative stability evaluated for eight days in an oven at 63 ± 3ºC. Results of hydroperoxide value (HP) and thiobarbituric acid reactive substances (TBARS) showed that NP-T had a similar performance as synthetic antioxidant BHT in the prevention of mayonnaise lipid oxidation