Valorization of brewers' spent grain and spent yeast through protein hydrolysates with antioxidant properties

• Type: Article in International Scientific Journal
• Date: 2016

Authors

Vieira, E (Author) Other; Teixeira, J (Author) Other; Ferreira, Isabel (Author) FFUP

Journal

Title: European Food Research and Technology

Vol. 242

Pages: 1975-1984

ISSN: 1438-2377

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 3 Citations

Scopus - 0 Citations

Other information

Authenticus ID: P-00K-F05

DOI: 10.1007/s00217-016-2696-y

Abstract (EN): Brewers' spent grain (BSG) and spent yeast (BSY) are the main by-products of the brewing industry, with currently limited valuable applications. However, BSG protein fraction can be a valuable substrate for enzymatic hydrolysis to produce hydrolysates with biological properties and BSY contains numerous vacuole proteases, which can be used to obtain these hydrolysates. Thus, the objective of this work was to explore the valorization of these two brewing by-products, based on the production of BSG protein hydrolysates that present antioxidant properties. Response surface methodology was employed to optimize the hydrolysis of BSG proteins using BSY proteases, based on degree of hydrolysis (DH %), total phenolic content (TPC) and antioxidant activity (FRAP assay). Reversedphase chromatography was also used to monitor the hydrolysis rate (HR %), and the potential presence of endogenous and other inhibitors of BSY proteases was also investigated. BSG protein hydrolysate prepared at 50 degrees C, pH 6, for 6 h and using an enzyme/substrate ratio of 0.29:1 U/mg presented maximum bioactivity with DH % of 17.10 %, TPC of 1.65 mg GAE/mL and FRAP value of 1.88 mg Trolox equivalent/mL. A good correlation was obtained between HR (%) and DH (%) (R-2 = 0.928). The experimental values agreed with the predicted values (p < 0.05), suggesting a good fit between the models and the experimental data. BSY proteases involved in the hydrolysis of BSG proteins are serine peptidases and metallopeptidases.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10