Abstract: In this study, papain tenderization was applied for the air-drying processing of spent laying hen breast meat. In order to evaluate the influence of air-drying ripening on the tenderization of chicken breast meat, predictive modeling for proteolysis index (PI) and Warner-Bratzler shear force (WBS) as separate responses to enzyme dose and air-drying temperature and time were conducted using central composite design (CCD). Based on the models established, the optimum levels of the three factors were determined to be: enzyme dosage, 3.5 U/g; air-drying temperature,14 ℃ and air-drying time, 99.33 h, their sequential decrease order was enzyme dosage, air-drying temperature and air-drying time for influencing PI and air-drying time, enzyme dosage and air-drying temperature for influencing WBS, and a PI of 10.408% and a WBS force of 3.48 kg/cm2 were obtained under these conditions.

Key words: papain, spent hen, response surface methodology, tenderness, air-drying ripening