Evaluation of nutritional composition and technological functionality of whole American Bullfrog (Lithobates catesbeianus), its skin, and its legs as potential food ingredients

•Frog byproducts were source of proteins with all the essential amino acids.•Frog skin and complete frog samples were rich sources in glutamic acid.•Frog skin sample powder is a protein isolate while frog legs are a concentrate.•Unsaturated fatty acids dominated froǵs oil, where oleic acid was the most abundant.•Samples had superior oil absorption an emulsion capacity than other ingredients. Frog farming systems do not take advantage of their byproducts, which represents health risks and environmental pollution. The present study aimed to evaluate the proximate composition, amino acid, and fatty acid profile of American Bullfrog byproducts (whole frogs (WF), legs (LF), and skin (SF)) and their technological functionality. Results showed that WF, LF, and SF protein content was 47.6, 88.4, and 91.1% dry base (d.b.), correspondingly. Fat content resulted in 34.6, 3.2, and 4.2% (d.b.), respectively. Moreover, byproducts contain all the essential amino acids (23.8–46.6%), and the unsaturated fatty acids predominated the saturated fats. Samples showed water and oil absorption capacities of 1.8–2.6% and 1.8–4.0%, respectively, while oil and water emulsion capacities were 76.7–98.3% and 36.1–85.6%, correspondingly. Additionally, SF presented a gelling capacity in a 5% concentration. These results showed that frogs' byproducts have adequate nutritional and functional capacities, compared to other vegetable and animal flours used in the industry.