Ultrasonic pretreatment improved the antioxidant potential of enzymatic protein hydrolysates from highland barley brewer's spent grain (BSG)

Abstract

Highland barley brewer's spent grain (BSG), being China's brewing industry's major by-product is the focus of current research. The aim of the present study was to scrutinize the effects of ultrasound and heat pretreatments on enzymatic hydrolysis of highland barley BSG protein hydrolysates (HBSGPH) and evaluate the effect of enzymatic hydrolysis time on the antioxidant activity of hydrolysates by Alcalase. Different ultrasonic waves (40 and 50 kHz) and heat pretreatment temperatures (50 and 100°C) were chosen and the pretreatment time was 15, 30, and 60 min. The obtained results revealed that the ultrasound pretreatment of highland barley BSG protein at 40 and 50 kHz has significantly (P < 0.05) enhanced about 57 and 67% of oxygen radical absorption capacity of obtained hydrolysate over the untreated substrate. The 1,1-diphenyl-2-picrylhdrazl (DPPH) radical scavenging activity (DRSA) 28%, metal chelating activity (MCA) 54%, superoxide radical scavenging activity (SRSA) 18%, and hydroxyl radical scavenging activity (HRSA) 25% of HBSGPH at 50 kHz were also improved (P < 0.05) significantly. HBSGPH from heat treatment at 100°C showed no SRSA and HRSA scavenging activities but improved significantly (P < 0.05) about 27% ferric reducing antioxidant power (FRAP) assay values. In the present work, the resultant HBSGPH had stronger antioxidant properties with ultrasound pretreatment at 50 kHz and the enzymatic hydrolysis after 4 hr was facilitating the enzymatic release of antioxidant peptides from HBSGPH.Practical Application: Highland barley BSG is attracting toward natural food products due to its potent natural antioxidants to overcome the risk of diseases and are beneficial for human health.

Spent Grain from Malt Whisky: Assessment of the Phenolic Compounds

“…The 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity of the pre-treated SG was evaluated by adding 2 mL of each sample with 2 mL of DPPH solution 0.1 mM in methanol (9.85 mg DPPH dissolved in 250 mL methanol) [ 51 ]. The mixture was shakenfor 2 min and was kept at room temperature, in a dark place, for 30 min, and then the absorbance was determined at 517 nm using a UV-VIS-NIR spectrophotometer (Schimadzu Corporation Kyoto, Japan).…”

Barley Protein Properties, Extraction and Applications, with a Focus on Brewers’ Spent Grain Protein

“…Enzymatic hydrolysis of barley proteins can greatly improve antioxidant capabilities and metal-binding activity [ 100 , 101 , 102 ]. A study by Chanput et al (2009) examined the antioxidant properties of partially purified proteins from a variety of sources, including barley hordeins.…”

“…The treatments selected were an ultrasonic treatment of 40 or 50 kHz and a heating treatment of 50 and 100 °C, while the pre-treatment times were 15, 30 and 60 min. The ultrasonic treatment at 40 and 50 kHz was shown to significantly increase oxygen radical absorption capacity values of the hydrolysates, while the heat treatment at 100 °C greatly increased the ferric reducing antioxidant power (FRAP) assay values [ 100 ]. These results indicate that hydrolysed BSG proteins exhibit a higher antioxidative power than untreated material and that these antioxidative capabilities can be further increased with ultrasonic and heat pre-treatments.…”

Quality Characteristics of Spelt Pasta Enriched with Spent Grain

“…Total antioxidant activity was determined by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) by adding 2 mL of extract described above with 2 mL of DPPH solution 0.1 mM in methanol (9.85 mg DPPH dissolved in 250 mL methanol), as described by Ikram et al, 2020 [30]. The mixture was shaken for 2 min and kept for 30 min at room temperature, in a dark place, and then the absorbance was determined at 517 nm using a UV-VIS-NIR spectrophotometer (Schimadzu Corporation, Kyoto, Japan).…”