Exploring the bioactive potential of brewers spent grain ohmic extracts

Ohmic based brewer's spent grain (BSG) hydro-ethanolic extracts were produced and their composition and biological potential through evaluation of their antibacterial, antibiofilm and antihypertensive activities were characterized. Ohmic Heating Extraction (OHE) was performed using two aqueous extractions of ethanol (60 and 80% ethanol:water (v/v)). A polyphenolic profile was performed and 4-hydroxybenzoic acid was the compound displaying the highest concentration (125.86 μg/g BSG) and the extract of 60% (v/v) hydro-ethanolic solution was the one with highest antioxidant activity (30.70 mg ascorbic acid/g BSG). Nevertheless, both extracts proved to have no mutagenic activity, and both were capable of inhibiting 50% of the angiotensin-I converting enzyme (ACE) enzyme, the most effective being the one obtained using 80% ethanol:water (v/v). BSG extracts displayed an inhibitory effect against Bacillus cereus at 2.50 and 0.625 mg/mL, for 80% (v/v) and 60% (v/v) ethanol:water, respectively and to a lesser extent against Listeria monocytogenes, at 5.00 and 2.50 mg/mL, for 80% (v/v) and 60% (v/v) ethanol:water, also the same concentrations inhibited biofilm formation.