Oxidative and microbiological stability of raw ground pork during chilled storage as affected by Plant extracts

The aim of this study was to investigate the quality changes of raw ground pork with the addition of allspice, bay leaf, black seed, caraway, cardamom, cloves or nutmeg extract and stored at 4°C. Lipid oxidation was evaluated by the peroxide value (POV), conjugated diene (CD) content, oxidation induction period (IP) by differential scanning calorimetry (DSC), thiobarbituric acid reactive substances (TBARS), and hexanal content; whereas protein oxidation by the thiol group content. Moreover, total viable aerobic bacteria count (TVC), Pseudomonas, Enterobacteriaceae, and lactic acid bacteria growths, pH and finally color of all samples were determined. POV, CD, TBARS and thiol group content were found to be highly correlated. Clove extract showed the highest antioxidant activity (1443 μM/g) and total phenolic content (TPC = 167 mg/g) and was the most effective antioxidant and antimicrobial agent in raw ground pork (TBARS = 0.31 mg/kg, POV = 5.1 meq O2/kg, thiol group content = 49 nmol/mg, IP = 68 min, TVC = 6.74). Cardamom and caraway also increased the oxidative stability of raw pork significantly (TBARS were equal to 0.3 and 0.28 mg/kg, POVs to 4.9 and 4.5 and thiol group content to 48 and 49 nmol/mg, respectively), despite their low antioxidant activities (72 and 300-fold lower than for cloves, respectively) and TPCs (1.2 and 2.4 mg/g). The results suggested that the application of natural antioxidants like spice extracts could enhance the stability and safety of raw ground pork, thus increasing its shelf-life