Availability of Lysine and Cysteine in Poultry Frankfurters made with Nitrite or Sorbate

Abstract

Four groups of poultry frankfurters made with mechanically deboned poultry (MDP) were prepared with: 1) control (no additives), 2) 156 ppm sodium nitrite, 3) 40 ppm nitrite and .26% potassium sorbate, and 4) .26% sorbate. Treatments were analyzed for total and available lysine and cysteine before processing and after storage at 4 C for 2 weeks. Lysine bioavailability using chicks was determined for control and nitrite frankfurters, while chick sulfur-amino acid bioavailability tests were conducted on the control and sorbate frankfurters.Available lysine values ranged from 13 to 14 g/100 g protein for MDP, frankfurter emulsions, and fresh frankfurters. Stored nitrite and nitrite-sorbate frankfurters contained significantly less lysine, 12 g/100 g protein, than the raw mechanically deboned meat.Chemical availability levels of cysteine were .6 g/100 g protein for MDP, while the emulsions had approximately .5 g/100 g protein. There was a heating effect, because both the fresh and stored frankfurter levels contained approximately .35 g/100 g protein. There was slight reduction of cysteine concentration in the nitrite frankfurters. Total cysteine remained stable in the MDP, emulsions, and fresh frankfurters, approximately 1 g/100 g protein. However, in the stored frankfurters, total cysteine declined slightly.From the chick lysine bioavailability test, it was concluded that there were no differences between nitrite and control frankfurters. The chick bioassays for available sulfur amino acids were comparable for sorbate and control frankfurters.