The fluid transport phenomenon in the chicken nuggets was monitored by frying the chicken nuggets in oil mixed with thermostable, fat-soluble Sudan red B dye. The dye was insoluble in water and found to have similar penetration behavior as that of frying oil (Keller et al., 1986). Dyed oil was prepared by dissolving 1 g of Sudan red B (SigmaeAldrich, St. Louis, MO, USA) for every 1 L of oil. The oil was heated to 60 C and the dye was mixed in the oil to make a uniform solution for 4 h.