Technological Benefits Associated with the Use of Spray-Dried Animal Plasma in Fish-Based Chunks for Canned Pet Food

SIMPLE SUMMARY: Fish and fish by-products are excellent sources of high-quality protein for cats and dogs. However, the handling, processing, and storage of raw materials can increase variation and negatively impact their technological properties. This study aimed to evaluate the use of spray-dried animal plasma (SDAP) as a binder in fish by-products recipes for chunks in gravy. The results showed that the inclusion of SDAP in recipes significantly improved the consistency (hardness), elasticity (springiness), cohesiveness, chewiness, and juiciness of the final wet products. These improvements were observed in a chunk recipe with a 35% content of mixed salmon and tuna by-products, and another recipe with chunks having a final content of a 4% salmon by-product. There was a positive linear effect of increased SDAP inclusion in the recipes for most of the technological parameters measured such as elasticity, flexibility, juiciness, and hardness. Our findings indicate that SDAP is an excellent nutritional binder that can enhance the final technological properties of wet pet food products using high-quality fish recipes and potentially in recipes containing protein-rich fish by-products with low functionality. ABSTRACT: Spray-dried animal plasma (SDAP) and wheat gluten (WG) are common binders in wet pet food that provide amino acids and energy, as well as texture and cohesiveness due to their gelling strength, water retention and fat emulsion properties. Binder use is a valuable tool especially in recipes based on ingredients with low technological properties such as fish by-products containing spines and scales and soft texture after cooking. Two basal recipes for chunks in gravy were produced to evaluate experimental treatments. One basal recipe used a mixture of salmon and tuna by-products as the only animal protein sources without binders or with a 20 g/kg inclusion of SDAP or WG. The other basal recipe mimicked a more typical commercial recipe containing meat animal ingredients and a 40 g/kg salmon by-product to develop experimental treatments with and 0, 10, 20, 30 or 40 g/kg inclusions of SDAP. Dry matter, protein, and viscosity were evaluated in raw emulsions. After a 1 h retorting at 121 °C, hardness was measured in emulsions and in cooked chunks, juiciness, and Texture Profile Analysis (TPA) were assessed. Results demonstrated the viability of producing quality chunks in gravy containing only fish by-products including 20 g/kg of SDAP, which significantly increased hardness, elasticity, cohesiveness, and juiciness. There was a positive linear correlation of increased SDAP inclusion rate in the commercial recipe for most of the quality parameters evaluated. Based on these results, the inclusion of SDAP in fish recipes can help manufacturers achieve technological quality control targets for commercial wet pet food and may help producers to successfully formulate new recipes for wet pet food products using fish by-products as the sole animal protein source.