Effect of high-pressure processing and <i>Thuja occidentalis</i> leaf powder on the quality, stability, and shelf life of chicken meat patties

Abstract This study investigates the combined effects of high-pressure processing (HPP) and Thuja occidentalis leaf powder (TLP) on the quality and shelf stability of chicken patties during refrigerated storage (0, 7, and 14 days). Key parameters analysed included microbial counts (total bacterial count and coliforms), haem pigments (myoglobin, oxymyoglobin, metmyoglobin), Hunter colour values (L*, a*, b*), thiobarbituric acid reactive substances (TBARS), peroxide value (POV), antioxidant activity (DPPH assay), total phenolic content (TPC), and total volatile basic nitrogen (TVB-N). A total of nine treatments were prepared, including patties treated with TLP and HPP at 300 MPa and 500 MPa and stored in polyethylene bags at 4 ± 1 °C for 14 days. Results showed that untreated control samples had significantly higher microbial counts, while the combination of 500 MPa HPP and 5% TLP completely suppressed microbial growth (100% reduction), and 300 MPa HPP with 5% TLP achieved ~ 76% reduction compared with the control. Treated samples exhibited a notable decline in myoglobin and oxymyoglobin over time, contrasting with an increase observed in the control. Metmyoglobin content rose with pressure treatment but declined with increasing TLP levels. TBARS values, an indicator of lipid oxidation, were highest in the control and lowest in samples containing 5% TLP. HPP and TLP also influenced colour stability, with Hunter values improving under pressure treatments but deteriorating in control samples. POV increased significantly in the control group during storage, while the treated samples demonstrated a slower rise, indicating improved oxidative stability. The highest antioxidant activity (DPPH) and TPC were recorded in patties with 5% TLP, whereas the lowest values were observed in samples treated with 300 MPa HPP alone. TVB-N, a marker of protein degradation, was highest in the control and lowest in the combination of 500 MPa HPP and 5% TLP. Sensory evaluation indicated significant changes in taste, texture, colour, odour, and overall acceptability during storage. This study provides valuable insights into how the combined use of natural antioxidants and high-pressure technology can help improve the quality, safety, and shelf life of meat products.