scholarly journals High-Pressure Homogenization Pretreatment before Enzymolysis of Soy Protein Isolate: the Effect of Pressure Level on Aggregation and Structural Conformations of the Protein

Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1775 ◽  
Author(s):  
Fei Zhao ◽  
Daofang Zhang ◽  
Xiangyang Li ◽  
Haizhou Dong

The high-pressure homogenization (HPH) treatment of soybean protein isolate (SPI) before enzymatic hydrolysis using bromelain was investigated. Homogenization pressure and cycle effects were evaluated on the enzymatic degree of hydrolysis and the antioxidant activity of the hydrolysates generated. The antioxidant activity of SPI hydrolysates was analyzed by 1,1-dipheny-2-picrylhydrazyl (DPPH). The sizes and structures of the SPI-soluble aggregate after HPH treatment were analyzed using dynamic and static laser light scattering. The changes in the secondary structure, as measured by Fourier transform infrared spectroscopy (FTIR) and the macromorphology of SPI, were measured by scanning electron microscope (SEM). These results suggested that the HPH treatment (66.65%) could increase the antioxidant activities of the SPI hydrolysates compared with the control (54.18%). SPI hydrolysates treated at 20 MPa for four cycles obtained higher DPPH radical-scavenging activity than other samples. The control was predicted to be a hard sphere, and SPI treatment at 10 MPa was speculated to be Gaussian coil, polydisperse, and then the high-pressure treated SPI became a hollow sphere. Changes in the secondary structures showed protein aggregate formation and rearrangements. The image of SPI varied from a globular to a clump structure, as observed by the SEM. In conclusion, combining HPH treatment and enzymolysis could be an effective way to improve the antioxidant activity of the SPI.

Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3637 ◽  
Author(s):  
Fei Zhao ◽  
Xuemei Liu ◽  
Xiuzhen Ding ◽  
Haizhou Dong ◽  
Wentao Wang

The objective of this study was to investigate the effects of different high-intensity ultrasonication (HIU) pretreatment on the structure and properties of soybean protein isolate (SPI) as well as enzymatic hydrolysis of SPI by bromelain and antioxidant activity of hydrolysates. The HIU-treated SPI fractions showed a decrease in the proportion of α-helices and β-turns and an increase in the content of β-sheets and random coils based on Fourier-transform infrared spectroscopy. Near-infrared spectra and fluorescence spectra analyses provided support for the changes in secondary and tertiary structures of SPI after ultrasound treatment. The particle size of SPI decreased from 217.20 nm to 141.23 nm and the absolute zeta potential increased. Scanning electron microscopy showed that HIU treatment changed apparent morphology. Dynamic and static light scattering of ultrasonicated samples showed that SPI structure had changed from hard-sphere to hollow-sphere or polydisperse and monodisperse gaussian coils. HIU pretreatment significantly increased the hydroxyl-radical scavenging and the degree of hydrolysis of the SPI hydrolysates.


2014 ◽  
Vol 881-883 ◽  
pp. 811-814 ◽  
Author(s):  
Rui Wen Yang ◽  
Jia Wang ◽  
Song Yi Lin

The soybean protein was hydrolyzed by Alcalase Food grade (FG) 2.4 L and the degree of hydrolysis (DH) were determined. The DH increased with the hydrolysis time increasing during 3.0 h. Then the hydrolysates was isolated by ultrafiltration membrane (1, 3, 10 kDa) and antioxidant activity was evaluated based on DPPH radical scavenging activity. The fraction of 1-3 kDa possessed the higher antioxidant activity than the other fractions (P < 0.05). Sephadex G-25 gel column was used to purify the three kinds of peptides and the eluted volume was investigated.


Author(s):  
Ir. Yusro Nuri Fawzya, MSi ◽  
Nugrah Analiadi Putra ◽  
Arif Budi Witarto ◽  
Gintung Patantis

Golden sea cucumber or locally known as “teripang emas” is one of Indonesia’s most popular sea cucumber and widely processed as functional food or supplement due to its bioactivities. The sea cucumber is often misidentified due to its morphological similarities with other Stichopus spp. This study aimed to identify the golden sea cucumber obtained from West Nusa Tenggara, Indonesia, by a molecular method and study the antioxidant activities of its collagen hydrolysates. The hydrolysates were produced by hydrolyzing acid collagen extract using neutrase for 30, 60, 120, 180, and 240 mins. The products were then analyzed for their degree of hydrolysis, peptide content, molecular weight distribution and radical scavenging activity by the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) method. Results showed that hydrolysis for 180 mins was optimal in producing the highest peptide content, 12.79 ± 0.44 mg/mL, with a degree of hydrolysis (DH) of 55.2 ± 1.50%. However, the highest antioxidant activity (IC50 of 5.25 ± 0.15 mg/mL) was demonstrated after 60 mins hydrolysis with molecular weight (MW) ranged from less than 14.4 kDa to approximately 25 kDa. The hydrolysate might be categorized as a weak to moderate antioxidant. Based on the molecular identification, the golden sea cucumber had 99% similarities with Stichopus horrens and S. monotuberculatus. 


2011 ◽  
pp. 151-157 ◽  
Author(s):  
Marijana B. Saka ◽  
Julianna F. Gyura ◽  
Aleksandra Mišan ◽  
Zita I. Šereš ◽  
Biljana S. Pajin ◽  
...  

The antioxidant activity of cookies prepared by the addition of sugarbeet dietary fibers was investigated in order to estimate their influence on functional characteristics and shelf-life of cookies. Treated fiber (TF) was obtained from sugarbeet by extraction with sulfurous acid (75 °C at pH = 5.7during 60 min) and treatment with hydrogen peroxide (20 g/LH2O2 at pH = 11 during 24 h). The fiber obtained was dried (80 °C), ground and sieved. TF was investigated in comparison with commercially available Fibrex®. The cookies were prepared by the addition of 0, 7, 9 and 11% of sugarbeet dietary fiber as a substitute for wheat flour in the formulation of cookies. The antioxidant properties of cookies were tested every 7 days using a DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity test during 6 weeks of storage at room temperature (23 ± 1 ºC). The obtained results indicated that substitution of wheat flour with Fibrex® in the formulation of cookies upgraded the antioxidant activity, i.e. the functional characteristics of Fibrex®-enriched cookies and could prolong their shelf-life. In contrast, TF did not increase the antioxidant activity of TF-enriched cookies. The better antioxidant activities of Fibrex®-enriched cookies could be attributed to the presence of ferulic acid.


2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
K. Nagendra Prasad ◽  
Jing Hao ◽  
Chun Yi ◽  
Dandan Zhang ◽  
Shengxiang Qiu ◽  
...  

Antioxidant activities of wampee peel extracts using five different solvents (ethanol, hexane, ethyl acetate, butanol and water) were determined by using in-vitro antioxidant models including total antioxidant capability, 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity, reducing power, and superoxide scavenging activity. Ethyl acetate fraction (EAF) exhibited the highest antioxidant activity compared to other fractions, even higher than synthetic antioxidant butylated hydroxyl toluene (BHT). In addition, the EAF exhibited strong anticancer activities against human gastric carcinoma (SGC-7901), human hepatocellular liver carcinoma (HepG-2) and human lung adenocarcinoma (A-549) cancer cell lines, higher than cisplatin, a conventional anticancer drug. The total phenolic content of wampee fraction was positively correlated with the antioxidant activity. This is the first report on the antioxidant and anticancer activities of the wampee peel extract. Thus, wampee peel can be used potentially as a readily accessible source of natural antioxidants and a possible pharmaceutical supplement.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Sushil Kumar Middha ◽  
Talambedu Usha ◽  
Veena Pande

This study revealed polyphenolic content, nutritive content, antioxidant activity, and phenolic profile of methanol and aqueous extracts ofPunica granatumpeel extract. For this, extracts were screened for possible antioxidant activities by free radical scavenging activity (DPPH), hydrogen peroxide scavenging activity and ferric-reducing antioxidant power (FRAP) assays. The total phenolics and flavonoid recovered by methanolic (MPE) and the water extract (AQPE) were ranged from 185 ± 12.45 to 298.00 ± 24.86 mg GAE (gallic acid equivalents)/gm and 23.05 ± 1.54 to 49.8 ± 2.14 quercetin (QE) mg/g, respectively. The EC50of herbal extracts ranged from 100 µg/ml (0.38 quercetin equivalents), for AQPE, 168 µg/ml (0.80 quercetin equivalents), for MPE. The phenolic profile in the methanolic extracts was investigated by chromatographic (HPLC) method. About 5 different flavonoids, phenolic acids, and their derivatives including quercetin (1), rutin (2), gallic acid (3), ellagic acid (4), and punicalagin as a major ellagitannin (5) have been identified. Among both extracts, methanolic extract was the most effective. This report may be the first to show nutritive content and correlation analysis to suggest that phenols and flavonoids might contribute the high antioxidant activity of this fruit peel and establish it as a valuable natural antioxidant source applicable in the health food industry.


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