The researchers studied what happens to nitrite in cured meat. They found that most of the added nitrite was detected as different compounds in the meat, with a small amount remaining unidentified. By separating pork into different fractions and adding nitrite, they discovered that the presence of sodium ascorbate helped detect more nitrite in the meat fractions. This suggests that the unknown nitrite in cured meat likely comes from the reaction between specific meat fractions, nitrite, and sodium ascorbate.