Antioxidant effect of spent, ground, and lyophilized brew from roasted coffee in frozen cooked pork patties

- Pork with coffee exhibited comparable TBARS values to pork with rosemary oleoresin.
- Aldehydes were lowest with added lyophilized brew compared to whole or spent coffee.
- Thiol content remained stable for all treatments under frozen conditions.
- Coffee inhibited lipid oxidation without adverse effects on protein oxidation.

The ability of light and dark roasted coffee (1 g/kg) in varying application forms (spent ground [SCG], whole ground [WGC], or lyophilized brew [LBC]) to inhibit lipid and protein oxidation in cooked pork patties stored at −18 °C was monitored over 3 months. Malondialdehyde (MDA) for the negative control (NC) increased from 0.31 to 1.11 mg MDA/kg pork over 3 months, while pork with coffee or rosemary oleoresin had lower values at month 3 (0.054-0.40 mg MDA/kg pork). The NC had the highest values for hexanal, octanal, and nonanal (2.59, 0.10, and 0.13 mg/kg pork, respectively), while light and dark LBC in pork inhibited hexanal (0.37 and 0.39 mg/kg pork), octanal (0.017 and 0.021 mg/kg pork), and nonanal (0.036 and 0.048 mg/kg pork) to the same extent as rosemary oleoresin at month 3 (0.30, 0.015, 0.036 mg aldehyde/kg pork, respectively). Thiol content for all treatments remained relatively stable from month 0-3 (0.56-0.96 to 0.67-1.02), while metmyoglobin slightly increased (49-55% to 55-56%) over 3 months. The results suggest that adding coffee neither inhibited nor promoted protein oxidation in cooked pork patties but inhibited lipid oxidation resulting in comparable values to pork with added rosemary oleoresin.