Effects of heating or ultrasound treatment on the enzymolysis and the structure characterization of hempseed protein isolates

Abstract

The effects of heating (90°C/30 min) or ultrasound (200/400/600 W) treatment on antioxidant and angiotensin-converting enzyme inhibitory (ACEI) activity of hydrolysates from hempseed protein isolates (HPI) were studied. The secondary structure, surface hydrophobicity, intrinsic fluorescence, scanning electron microscopy (SEM) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of HPI treated by heating or ultrasound were measured. The results showed that hydrolysate from HPI treated with ultrasound at 200 W showed higher hydrolysis degree, proportion of lower molecular mass components (1.0-3.0 kDa), antioxidant and ACEI activity than those from heating or high-power treated. The changes in secondary structure, surface hydrophobicity and intrinsic fluorescence indicated the unfolding of HPI after ultrasound. The SEM results showed that HPI treated with ultrasound at 200 W exhibited decrease in particle size and deformation and further increased in power caused the aggregates of HPI. In conclusion, the ultrasound treatment at low-power was superior to 90°C/30 min treatment in facilitating enzymatic release of antioxidant and ACEI peptides from HPI.

Effects of ultrasound assisted cell wall disruption on physicochemical properties of camellia bee pollen protein isolates

“…The measurement for secondary structure of proteins samples (0.2 mg/mL) were performed using a Mos-450CD spectropolarimeter (Biologic, Claix, France) [26] and secondary structure was calculated by computer program CDPro ( http://lamar.colostate.edu/sreeram/CDPro/main.html ). For submits analysis, the sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) was carried out on a Bio-rad Mini-Protein Tetra Electrophoresis System (Hercules, USA) with a 12 % separating gel and a 5 % stacking gel according to previous study [27] . Freshly prepared loading buffer with 4 mg/mL protein content was used in SDS-PAGE test.…”

Effects of high‐intensity ultrasound treatment on physiochemical properties of caseins‐cyanidin‐3‐galactoside conjugates

“…As an eco-friendly technology, ultrasound is widely applied for modification of food quality. Ultrasound treatment could induce the unfolding of protein, which resulted in improvement of functional properties and increasing of accessibility to polysaccharides and enzymes (Li et al, 2014;Xue et al, 2017;Li et al, 2018;Xue et al, 2018b;Wang et al, 2019). It has been proved that ultrasound field in liquids can produce free radicals such as H • , HO • and HO • 2 (Merouani et al, 2014).…”

Nutritional Quality, Chemical, and Functional Characteristics of Hemp (Cannabis sativa ssp. sativa) Protein Isolate

“…Generally, most essential amino acid levels were satisfactory for the FAO/WHO daily requirements. Hemp protein isolate (HPI) previously was characterized as a rich source of glutamine, arginine, tyrosine, and phenylalanine, while it is limited in lysin, sulfur-containing amino acids, and tryptophan [ 1 , 33 , 34 ]. The digestibility and availability of hemp seed protein were higher than other plant proteins such as wheat and legumes [ 34 ].…”