Abstract
Exposing ingredients to high temperatures may result in chemical reactions between amino acids and sugars, leading to the formation of Maillard reaction products (MRPs). These products may result in altered palatability, protein quality, and digestibility. This experiment quantified key MRPs in commercial pet foods, estimated daily intake of MRPs of pet animals, and correlated MRPs with macronutrient concentrations present in the foods. The analysis included 53 pet foods and treats commercially available in the United States: 11 dry dog foods, 29 wet dog foods, 2 dry dog treats, 3 wet dog treats, 2 dry cat foods, and 6 wet cat foods. Diets and treats were analyzed for dry matter, organic matter, crude protein (CP), acid-hydrolyzed fat, total dietary fiber, and gross energy using standard techniques. MRPs were analyzed using high-performance liquid chromatography and gas chromatography-mass spectrometry. All data were analyzed as a completely randomized design using the GLM procedure of SAS 9.4. On average, wet foods had higher (P < 0.001) fructoselysine (FRUC) and carboxymethyllysine (CML) than dry foods. Dry dog treats had the highest (P < 0.001) FRUC (29.64 µg/g) and CML (0.47 mg/g) concentrations of all products tested. Dry cat foods had the lowest (P < 0.001) CML (0.10 mg/g) concentrations of all commercial segments. Wet dog treats had the highest (P < 0.001) 5-hydroxymethyl-2-furfural (HMF) (10.92 µg/g) concentrations of all segments and wet cat foods had the lowest (P < 0.001) HMF (0.22 µg/g) content. Dogs and cats fed wet diets would be more likely to ingest higher amounts of CML and FRUC compared to animals fed dry diets. Dogs consuming dry treats would be more likely to ingest higher amounts of CML than wet treats. CP was negatively correlated to HMF (P = 0.0425; r = -0.27973), while TSF was positively correlated to CML (P = 0.0417; r = 0.28080).