AMINO ACID PROFILE AND BIOACCESSIBILITY IN BROCCOLI SPROUTS

Broccoli sprouts are a source of nutrients and bioactive compounds, but information regarding their amino acid composition and changes during gastrointestinal digestion remains limited. This study aimed to characterize the amino acid profile of broccoli sprouts, determine the bioaccessibility of individual amino acids, and evaluate the adequacy of their essential amino acid profile. Broccoli sprouts were obtained after three days of germination. Proximate composition was determined and free and total amino acids were analyzed by high-performance liquid chromatography with fluorescence detection before digestion and in the intestinal fractions following the INFOGEST 2.0 protocol. Amino acid bioaccessibility was calculated, and aminoacid score (AAS) values were determined by comparing essential amino acid concentrations, expressed as mg/g protein, with the FAO reference pattern. Statistical comparisons were performed using multiple-comparison tests, with significance set at p < 0.05. On a dry-weight basis, broccoli sprouts contained 3.96% ash, 29.70% lipids, 32.18% protein, and 33.66% carbohydrates. This finding motivated further characterization of the amino acid profile to assess protein nutritional quality. Aspartic acid was the predominant amino acid (34.04 ± 2.78 mg/g dry matter), followed by glutamic acid (24.57 ± 2.52 mg/g). Among essential amino acids, lysine (20.13 ± 0.30 mg/g), valine (18.49 ± 2.46 mg/g), and leucine (15.14 ± 0.91 mg/g) showed the highest initial total concentrations. Histidine showed the highest essential amino acid bioaccessibility (154.19 ± 9.10%), followed by lysine (111.33 ± 15.41%), whereas valine (23.05 ± 6.22%), threonine (25.81 ± 4.72%), and isoleucine (27.72 ± 3.86%) showed the lowest values. AAS analysis identified leucine as the first limiting amino acid among those evaluated (76.38 ± 4.59%), followed by isoleucine (92.68 ± 4.50%). Scores above 100% were observed for lysine (129.02 ± 1.92%), threonine (142.18 ± 3.83%), and valine (132.10 ± 10.10%), indicating that these essential amino acids are present in amounts exceeding the corresponding values in the FAO reference amino acid pattern. Tryptophan was quantified only in the free amino acid fraction; therefore, its AAS could not be calculated. These findings should therefore be interpreted considering the methodological limitations of in vitro bioaccessibility assessment. The low gastrointestinal bioaccessibility of valine, threonine, and isoleucine suggests that amino acid composition alone may overestimate their potential nutritional contribution, highlighting the importance of considering gastrointestinal bioaccessibility when evaluating the potential nutritional quality of broccoli sprout proteins. Overall, broccoli sprouts showed a nutritionally relevant essential amino acid profile, with particularly favorable scores for lysine, threonine, and valine.

Agradecimentos: CAPES (proc.#001), CNPq (proc.#421008/2023-7), FAPERJ (proc.#E-26/211.844/202)