In Vitro Protein Disappearance of Raw Chicken as Dog Foods Decreased by Thermal Processing, but Was Unaffected by Non-Thermal Processing

SIMPLE SUMMARY: Chicken meat is widely used as a dog food due to its high nutritional values and palatability. Pasteurization is important to ensure the safety of chicken meat: thermal processing and non-thermal processing including high-pressure processing, ultraviolet-light emitting diode radiation, electron-beam irradiation, and gamma-ray irradiation. The influence of these pasteurization methods on nutrient digestibility is of interest. In the present work, the effects of thermal and non-thermal processing methods on protein digestibility of chicken meat were measured using in vitro assays. Protein digestibility of chicken meat was decreased by high-temperature processing at 70, 90, and 121 °C. However, non-thermal processing methods including high-pressure processing, ultraviolet-light emitting diode radiation, electron-beam irradiation, and gamma-ray irradiation did not affect protein digestibility of chicken meat. The present study indicates that nutritional values of chicken meat were maintained when non-thermal processing methods are used whereas they were decreased by thermal processing methods. ABSTRACT: The objectives of the present study were to determine the influence of thermal and non-thermal processing procedures on in vitro ileal disappearance (IVID) of dry matter (DM) and crude protein (CP) in chicken meat as dog foods using 2-step in vitro assays. In thermal processing experiments, IVID of DM and CP in chicken meat thermally processed at 70, 90, and 121 °C, respectively, with increasing processing time was determined. For non-thermal processing experiments, IVID of DM and CP in chicken meat processed by high-pressure, ultraviolet-light emitting diode (UV-LED), electron-beam, and gamma-ray was determined. Thermal processing of chicken meat at 70, 90, and 121 °C resulted in decreased IVID of CP (p < 0.05) as heating time increased. In non-thermal processing experiment, IVID of CP in chicken meat was not affected by high-pressure processing or UV-LED radiation. In vitro ileal disappearance of CP in electron-beam- or gamma-ray-irradiated chicken meat was not affected by the irradiation intensity. Taken together, ileal protein digestibility of chicken meat for dogs is decreased by thermal processing, but is minimally affected by non-thermal processing methods.