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

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 degrees C was monitored over 3 months. Malondialdehyde (MDA) for the negative control (NC) increased from 031 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. (C) 2015 Elsevier Ltd. All rights reserved.