DIGESTIBILITY EVALUATION OF PLANT-BASED BURGER ANALOGUES COMPARED TO BEEF BURGER: FREE AMINO ACIDS AND DEGREE OF HYDROLYSIS

Plant-based burger analogues (PBBAs) are commercially considered as alternative products to meat-based burgers (MBBs), but do not present the similarity in nutritional profile. Differences related to the formulation of products and their behavior during the gastrointestinal digestion process can directly impact the absorption of essential nutrients such as proteins, formed by amino acids joined by peptide bonds. Thus, the aim of the study to investigate the release of amino acids and the degree of hydrolysis (DH%) induced by the enzymatic activity after in vitro gastrointestinal digestion of PBBAs (chickpea and soybean) and beef MBB marketed in Brazil. Samples were roasted, ground, and homogenized to perform the assays in triplicate. The simulation of in vitro digestion followed the standardized INFOGEST 2.0 protocol. The free amino acids (FAA) content was determined following o-phthaldialdehyde (OPA) method, after discounting analytical blank. The DH% was determined by the ratio between the FAA content of the in natura and hydrolyzed samples. The highest average FAA content and DH% were obtained in beef MBB (11573.33 mg NH2 L-1, 95.43%) and soybean PBBA (10074.77 mg NH2 L-1, 95.30%), which did not differ statistically by the Tukey HSD test (95% confidence interval). The lowest average and significantly different FAA and DH% were found in chickpea PBBA (4648.33 mg NH2 L-1, 79.14%). The results showed that soybean PBBA have high FAA content and digestibility comparable to beef MBB. The lower release of NH2 groups of the chickpea PBBA could have been associated with nutrients' interferences to the digestive proteases, such as total fiber and polyphenols content in plant-based samples. Future studies are needed to know the amino acids profile present in these analogue products, as scientific literature reports that there are differences in the nutritional quality of proteins of animal and plant-based origin available for absorption.