Pet Food Processing—Understanding Transformations in Starch during Extrusion and Baking
Pet foods contain a multitude of ingredients as they must satisfy all of a pet's daily nutritional requirements, including carbohydrates, protein, fat, and micronutrients. Processing dry pet foods typically involves baking or extrusion. Extrusion has a number of advantages over conventional batch methods: a single extruder can perform several functions, and a wide variety of products can be processed using the same equipment by altering the processing conditions, screw profile, die, and ingredients. Due to the nature of the baking process, baking is a much lower throughput process compared with extrusion. Starch is an important part of a typical dry pet food formulation and undergoes several important changes during processing that impact the digestibility, palatability, and physical attributes of the final product. Notable starch-related phenomena include gelatinization and amylose-lipid complexation. Proximate analysis of dry pet foods after baking or extrusion confirmed that final products were isonutritional at the meat inclusion levels tested. Interactions between the various components of pet food formulations are complex, as are the physicochemical transformations that take place during processing.