Nutritional characterization and technological functionality of American bullfrog (Lithobates catesbeianus) byproducts as potential food ingredients

Abstract

The present dissertation consists of one manuscript covering a study in American Bullfrog's byproducts chemical characterization and technological functionality. The following chapters focused on the theoretical framework regarding frog farming, American bullfrog production in Mexico, frogs' nutritional composition, and food's technological functionality properties and parameters. In the same way, it includes scientific disclosure material and an appendix section with complementary data obtained during data analysis. Manuscript 1 is an article entitled "Characterization of the byproducts of American Bullfrog farming (Lithobates catesbeianus) towards novel food ingredients." Herein presents the chemical composition, amino acid profile, fatty acid profile, technological functionality, and statistical analysis of American Bullfrog byproducts. The proximal characterization of complete frogs (CF), frog legs (FL), and skin (SF) was made. Besides, the techno-functional properties measured were water emulsion capacity (WE), oil emulsion capacity (OE), water absorption (WAC), oil absorption (OAC), foaming capacity (FC), and protein solubility, and the statical analyzes where correlation analyzes among the samples composition and their functional properties, and principal component analysis (PCA) was also performed. The results showed that Mexican frogs' byproducts are a non conventional source of proteins, essential amino acids, unsaturated fatty acids. The samples presented high WAC, OAC, WE, and OE values, although low protein solubility and FC. Correlation analysis showed that technological functionality positively correlates with protein content and basic amino acid content and negatively with fat. PCA proved that two main components explain 95.85% of the variance and correctly separate the samples (CF, LF, and SF). The scientific disclosure chapters include a poster presentation and a document sublimed to the "Premio Rómulo Garza" award. The appendix section includes Correlation between fat and protein content of frogs 'byproducts (d.b.) with techno-functional properties, ANOVA analysis of the fatty acid, amino acid, and frogs' functional properties byproducts (d.b.), and the Eigenvectors of the correlation matrix. This dissertation showed that American bullfrog byproducts have a high nutritional value due to their protein, essential amino acids, and unsaturated fatty content. Besides, they present interesting emulsifying, absorption, and gelling properties, so they have potential applications as functional ingredients. These results could state the basis for implementing an industrial process that takes advantage of these byproducts as food additives or ingredients in food formulations. Moreover, its use will allow reducing the environmental and sanitary risk related to their disuse