Dry and Liquid Marination With Rooibos Extracts to Enhance Chemical and Microbiological Stability of Refrigerated Raw Minced Pork

The increasing demand for clean labels and sustainable food systems has driven research into natural antioxidants in food preservation. This study examined rooibos (Aspalathus linearis), a South African herbal plant abundant in polyphenols and flavonoids, possessing multifunctional bioactivity, as a natural antioxidant for meat preservation. The effect of rooibos extracts as marinades in raw minced pork during refrigerated storage was assessed, focusing on their implications for chemical and microbiological stability. Pork loin was marinated for 24 h with liquid and dried green and red rooibos extracts, containing equivalent amounts of total polyphenols. Subsequently, meat samples were minced and stored at 4°C for up to 13 days. Meat safety and stability were assessed during storage through physicochemical parameters, lipid oxidation indices, and microbiological indicators, including, peroxide value (PV), thiobarbituric acid reactive substances value (TBARS), oxidized coenzyme Q10, coliforms, biogenic amines, pH, color, and water activity (aw). Among the parameters evaluated, PV ranged from 0.16–1.44 and 0.21–1.07 meqO2/kg of meat in liquid and dry treatments, respectively. Liquid-marinated samples consistently showed aw values above 0.98, whereas dry-marinated samples ranged between 0.95 and 0.97. Biogenic amine index ranged between 5–10 mg/kg in dry-marinated samples, whereas liquid-marinated samples exceeded 50 mg/kg after 3 days. Dry marination efficiently counteracted malondialdehyde (MDA), coliforms and biogenic amines levels, meanwhile liquid marinade samples showed reduced PV and oxidized CoQ10. Overall, these findings suggest that rooibos extracts can act as supporting antioxidant ingredients offering a step toward sustainable and safe food preservation practices and clean-label trends.