Role of fermented and unfermented rooibos (Aspalathus linearis) in wet and dry marinades on oxidative status and sensory properties of pork meat subjected to different cooking methods

The antioxidant potential of Aspalathus linearis (rooibos), either fermented (FR) or unfermented (UR), used as a natural additive in dry or wet marinades for pork loin cooked using oven, pan, sous-vide and microwave methods was investigated. Their effect on lipid peroxidation (LP), on the content and oxidative status of coenzyme Q10 (CoQ10), on cooking-related meat weight loss and on sensorial properties were evaluated. All cooking methods increased LP endpoints, however pan-cooking lead to lower oxidation in terms of hydroperoxides (PV) (0.020 ± 0.003 mEq O₂/100 g in wet-marinated and 0.025 ± 0.000 mEq O₂/100 g in dry-marinated meat) and malondialdehyde (MDA) (0.124 ± 0.015 mg/100 g in wet-marinated and 0.163 ± 0.002 mg/100 g in dry-marinated meat). FR limited the increase in PV in dry-marinated samples cooked using oven (0.031 ± 0.007 mEq O₂/100 g), sous-vide (0.023 ± 0.007 mEq O₂/100 g) and microwave (0.260 ± 0.006 mEq O₂/100 g), compared to the control (C) (oven = 0.045 ± 0.004 mEq O₂/100 g sous-vide = 0.042 ± 0.003 mEq O₂/100 g, microwave = 0.046 ± 0.005 mEq O₂/100 g). For MDA levels, FR was effective in dry marinated and microwaved samples (C = 0.265 ± 0.061 mg/100 g, FR = 0.106 ± 0.026 mg/100 g) and in oven-cooked samples previously wet-marinated (C = 0.211 ± 0.022 mg/100 g, FR = 0.128 ± 0.005 mg/100 g) or dry-marinated (C = 0.247 ± 0.019 mg/100 g; FR = 0.159 ± 0.005 mg/100 g). Conversely, UR was able to significantly counteract both PV and MDA in oven, sous-vide and microwave cooked meat, regardless of the marinating technique used, proving even more effective in counteracting LP. On the other hand, FR seems to provide a more favourable sensory profile, particularly in samples cooked in the microwave with a wet marinade and in samples cooked in the oven with a dry marinade. The use of rooibos influenced CoQ10 oxidative status under certain conditions. This study demonstrates the ability of rooibos extracts to modulate early oxidative changes occurring during meat cooking, indicating its potential use as a natural alternative to synthetic preservatives.