Experiment I: Antioxidant activity of mustard seed extract

Yellow mustard seeds (B. juncea, bb Royal, India) were ground by grinder (DP-5800BL, Guangdong Xinbao Electrical Appliances Holdings, Guangdong, China) for 5 min at room temperature (23°C). The solvents which used for extraction were distilled water (DW) and ethanol, 5 different ratios (DW:ethanol; 0:100, 25:75, 50:50, 75:25, 100:0, v/v). The ground seeds were mixed with each solvent separately at a ratio of 1:10 and stirred for 24 h at room temperature. After centrifugation at 2,731×g for 30 min (Supra R22, Hanil, Daejeon, Korea), the filtrate of supernatant was stored at –80°C to freeze it before being freeze-dried by a freeze-dryer (FD12008, ilShinBioBase, Dongducheon, Korea). The 5 groups of freeze-dried extracts were dissolved in each solvent to make a stock (20%, w/v) used for experiments and loin ham manufacturing.

The ground seeds were weighed before extraction (initial weight), and the freeze-dried extracts were weighed again (final weight). The extraction yield percentage was calculated using the following formula: