Treats are offered to dogs to reinforce the animal-owner bond and as rewards. Wheat, which contains gluten (gliadin and glutenin proteins), is often used in treats. The United States is a leading producer of sorghum which might be an alternative; however, it does not have functional properties to form viscoelastic doughs, because it is mainly composed of kafirin protein. Therefore, the objectives of this study were to determine the effects of supplementing soluble animal proteins in whole sorghum rotary-molded baked dog treats on dog preference, sensory attributes, and oxidation rate. The treats were produced in triplicate in a 2 x 4 + 1 augmented factorial arrangement of treatments. Two whole sorghum flours (WWS and WRS), four protein sources [none (NC), spray-dried plasma (SDP), egg protein (EP), and gelatin (GL)], and a positive control with wheat (WWF-GTN) were evaluated. A preference ranking test with twelve dogs was performed. Additionally, five trained panelists scored the intensity of appearance, aroma, flavor, texture/mouthfeel, and aftertaste attributes. Finally, the treats were stored at 30 °C and 60% RH, and hexanal concentrations were measured on days 0, 28, 56, and 112. The data was analyzed using the statistical software SAS for the animal and oxidation rate evaluations with significance considered at P<0.05. The descriptive sensory evaluation data was analyzed using multivariate analysis (XLSTAT). The dogs did not detect differences among WWF-GTN, WWS, or WRS treats when evaluated together. However, the WWF-GTN, WWS-SDP, and WWS-EP treatments were preferred among the white sorghum treatments. The EP treatments led to some consumption difficulties by dogs because of their hard texture. The panelists reported a high degree of variation in the appearance and texture across treatments. The WRS and WWS treats with SDP or EP were darker, while NC treats had more surface cracks. Initial crispness, hardness, and fracturability were higher in EP treatments compared to all other sorghum treatments. The predominant flavor and aftertaste identified were "grainy." The hexanal values for all treats were <1.0 mg/kg except for the EP treatments that had higher values (2.0-19.3 mg/kg) across the shelf-life test. This work indicated that the replacement of WWF-GTN by WWS and WRS, along with soluble animal proteins like SDP or GL would produce comparable preference by dogs, oxidation rates, product aromatics, flavor, aftertaste attributes, and, at a lower degree, product texture.
Keywords: beagle dogs; descriptive panel; hexanal; oxidation; palatability; ranking test.
Treats are commonly given to dogs to create a better relationship with the owner. Most treats on the market are baked and wheat based as this grain has gluten that provides good texture attributes and facilitates production. Other grains such are sorghum are widely produced in the United States. However, baking treats with alternative grains is challenging as they lack the same functional proteins. The objectives of this study were to determine the effects of soluble animal proteins in whole sorghum rotary-molded dog treats on dog preference, sensory attributes, and oxidation markers, such as hexanal. Two whole sorghum flours [white (WWS) and red (WRS)], four protein sources [none (NC), spray-dried plasma (SDP), egg protein (EP), and gelatin (GL)], and a positive control with wheat (WWF-GTN) were evaluated. The dogs did not detect differences between WWF-GTN, WWS, or WRS treats when evaluated together. However, the EP treatments, because of their hard texture, led to some consumption difficulties. The panelists reported a high variation in the appearance and texture across treatments. Additionally, the predominant flavor and aftertaste identified were “grainy.” The hexanal values were not noticeable, except for the EP treatments that had higher concentrations across the duration of the evaluation.
© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society of Animal Science.