Papers by Keyword: Antioxidant Properties

Abstract: In this study, we research the long-term UV protective effect of BNNSs/PVB multilayer thin film coating on the properties of extra virgin olive oil. Boron nitride nanosheets (BNNSs) were synthesized using the liquid exfoliation method. BNNSs/PVB multilayer thin film was coated on tubes by dip-coating. After the UV irradiation of coated and uncoated glass tubes at different times, the total phenol content (TPC) and antioxidant activity of olive oil (TAA) were determined. Specific absorption coefficients K232 and K270 in the ultraviolet region were measured for estimating the oxidation degree of olive oil after irradiation. Free fatty acid (FFA) in olive oil after UV irradiation was determined by the titration method. Olive oil quality analysis indicates that BNNSs/PVB coating on the glass is effective on the protection of TPC and TAA of olive oil. In addition, the results show that extra virgin olive oil in the coated glass tube is maintained nearly 2 times more than the amount of phenol in the uncoated tube. While olive oil samples in glass tube coated with 30 and 50 times exceeded the limit of K270 value (0.22) after 400 hrs, it was determined that olive oil samples in uncoated glass exceeded this limit after 215 hrs. After 720 hours of UV irradiation, the free fatty acid value of the UCOL (uncoated) sample increased by 24.7% compared to the initial value, while the increase in the COL50 (coated) sample was 15%.

Abstract: Microalgae protein hydrolysates (MPH) were obtained by enzymatic hydrolysis of defatted microalgae meal using neutral protease. The protein recovery, degree of hydrolysis, and the antioxidant activities of the hydrolysates were investigated. The results demonstrated that hydrolysates prepared by neutral protease at 50 °C for 4 h exhibited the strongest antioxidant activity. Under these conditions, the 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical scavenging activity and the reducing power of the hydrolysates were 68.3%, 50.8% and 1.303, respectively.

Abstract: In this study, three kinds of component proteins of tilapia were hydrolyzed with papain for 4h. The effect of hydrolysis and the antioxidant activities of the resulting hydrolysates were characterized. The results showed sarcoplasmic protein hydrolysate had significantly (p < 0.05) highest scavenging ability against hydroxyl, superoxide, DPPH radicals and the total reducing power. Stroma protein hydrolysate had the highest nitrogen recovery (NR) while myofibrillar protein hydrolysate had the highest degree of hydrolysis (DH). Sarcoplasmic protein hydrolysate with high radical scavenging ability was separated by membrane ultrafiltration into four molecular size fractions (<5, 5–10, 10–100, >100kDa). It was found that the antioxidant activities of the <5kDa fraction were higher than that of other fractions. Overall, sarcoplasmic protein is more efficient to obtain antioxidant properties when compared to other component proteins of tilapia.

Abstract: Tilapia protein hydrolysates (TPH) were obtained by enzymatic hydrolysis of tilapia meat using papain, and then the TPH binded with copper at various mass ratios of TPH to CuCl₂ (5:1, 10:1 and 20:1) to obtain complex I, complex II and complex III, respectively. The copper-binding rate, antioxidant properties, and FTIR spectrum of the complex were investigated. It was found that the copper-binding rate increased with the increase of mass ratios (TPH/CuCl₂) from 5:1 to 20:1. The DPPH radical scavenging activity and reducing power activity of TPH were higher than that of the complexes. However, the lipid peroxidation inhibition activity was improved after TPH binded with copper. It was also found that the antioxidant activities of complex III were highest in the complexes. FTIR spectra demonstrated that some sites such as amino nitrogen atoms in TPH could bind with copper to form the complex.

Abstract: Deer blood was hydrolyzed using Alcalase with hydrolysis time ranged form 0 to 6 h, and the degree of hydrolysis (DH) of protein hydrolysates increased with increasing hydrolysis time (P < 0.05). The reducing power, radicals scavenging activities and Cu2+-chelation ability of deer blood hydrolysate (DBH) significantly enhanced with increasing hydrolysis time (P < 0.05). The antioxidant activity of DBH, indicated by thiobarbituric acid-reactive substance (TBARS) values in a liposome-oxidizing system, increased with increasing DH (P < 0.05). The results indicated that antioxidant activity of DBH depended on hydrolysis time, and the hydrolyzed deer blood could be a potent food antioxidant.

Abstract: Chroogomphis rutillus is an ectomycorrhizal edible mushroom available in China. The ethanolic, cold water and hot water extracts were prepared and their antioxidant properties studied. At 4 mg/mL, the ethanolic extract showed a high reducing power of 1.561, whereas those of cold water and hot water extracts were 1.161 and 0.808. With regard to the scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals, extracts were effective in the order: ethanolic > cold water > hot water extracts. EC₅₀ values for chelating ability on ferrous ions for ethanolic, cold water and hot water extracts were 15.755, 0.059, and 0.067 mg/mL, respectively. Based on EC₅₀ values, the various extracts from C. rutillus were effective antioxidants.