PROTEIN-TO-FILM ADHESION AS EXAMINED BY AMINO ANALYSIS OF PROTEIN-BINDING TO 3 DIFFERENT PACKAGING FILMS

A weak protein solution extracted from chicken breast meat was exposed to three types of packaging materials. Te crude myofibrillar protein solution (12.0 mg protein/mL buffer) was suspended in a 0.6M NaCl/NaPO 4 buffer, then placed in bags made from either polyethylene (nonbindin g film), a nylon blend (binding film), or Surlyn(TM) (binding film). T wo separate experiments were conducted to determine the effects of exp osure time at a constant temperature and varying endpoint exposure tem peratures on the amount of bound protein by amino acid analysis. Bound amino acids were quantified and grouped by class based on functional side group. It was theorized that differences in the amount of bound a mino acid class was linked to the mechanism by which the meat-to-film binding occurs. The protein solution was sealed in bags and held in a water bath for 5 s, 20 min, 40 min, and 60 min at 25.8 C for the timed experiment and heated from 25.8 C to 40, 55, 70, and 80 C. for the te mperature experiment. Protein adhesion occurred due to exposure of the solution to all films at 25.8 C. Greater protein adhesion was found i n the two binding films than in the nonbinding film after 60 min of ex posure. Heating the protein solution, increased adhesion for the Surly n(TM) film and showed a clear delineation in the degree of binding bet ween the film types. Surlyn(TM) bound the most protein, followed by th e nylon blend and then polyethylene. Bound protein increased in the Su rlyn(TM) film with heating to 80 C, whereas the polyethylene did not s how an increase in the amount of bound protein. Increases in binding o bserved between 55 and 80 C for Surlyn(TM) may be associated with tran sitional and conformational changes in muscle proteins that affect the adhesion of meat to the film surface.