Dados do Trabalho

Título

ENZYMATIC HYDROLYSIS OF BREWER'S SPENT YEAST TO RECOVER ANTIHYPERTENSIVE PEPTIDES

Introdução

Beer is the most popular alcoholic drink worldwide. However, its production generates a lot of waste, mostly from the hops, malted barley, and yeast. The brewer’s spent yeast represents 15% of the total generated waste. Thus, Alternatives are demanded to provide better utilization of the brewer’s spent yeast. Studies have highlighted potential biological activities beneficial to human health on the brewer’s spent yeast. Some biological activities, such as antihypertensive, can be associated with peptides that come from hydrolyzed proteins that act to inhibit the angiotensin-converting enzyme (ACE). In this sense, this study aims to evaluate the antihypertensive potential of peptides from enzyme-catalyzed hydrolysis of two types of brewer’s spent yeast: Saccharomyces pastorianus and Saccharomyces cerevisiae.

Material e Métodos

Initially, freeze-dried brewer’s spent yeast samples were characterized in terms of protein, lipids, ash, and carbohydrates. The brewer’s spent yeasts were enzymatic hydrolyzed (Flavourzyme®, 3 h, 50 ºC at pH 7), and, after centrifugation, the precipitate was discarded. The supernatant fractions were submitted to an ultrafiltration process (molecular weight cut-off equal to 5 kDa, 25 ºC at 0.5 MPa). The hydrolyzed, retentate, and permeate fractions were used to measure the in vitro ACE-inhibitory activity.

Resultados e Discussão

The S. pastorianus exhibited a protein content of 43.47±0.70%; ash of 3.80±0.14%; lipids of 0.46±0.14% and carbohydrates of 51.43% (by difference). In contrast, S. cerevisiae presented 29.25±0.25%; 2.39±0.13%; 1.05±0.25%, and 65.63%, respectively. The permeate fraction (peptides<5 kDa) showed 72.15±9.22% and 57.63±12.48% of ACE-inhibitory activity for S. pastorianus and S. cerevisiae, respectively. These values of ACE-inhibitory activity were statistically (p<0.05) equal to those found when enalapril maleate (63.69±2.42%) was used at the same concentration in the control assay. In the retentate fractions (peptides≥5kDa) the ACE-inhibitory activity observed for S. pastorianus (18.28±6.94%) and S. cerevisiae (24.98±10.73%) did not present statistical differences between them, but the values were lower than observed for permeate fraction.

Conclusão

The ACE-inhibitory activity was directly affected by the peptide molecular weight regardless of the brewer’s spent yeast used. Finally, it was possible to verify the potential of antihypertensive peptides from brewer’s spent yeast, which showed similar ACE-inhibitory activity to medications commonly used to treat hypertension.