scholarly journals Antioxidant properties of high molecular weight compounds from coffee roasting and brewing byproducts

2019 ◽  
Vol 2 (3) ◽  
pp. 48 ◽  
Author(s):  
Amaia Iriondo-DeHond ◽  
Beatriz Ramírez ◽  
Francisco Velazquez Escobar ◽  
María Dolores del Castillo
Keyword(s):  
Molecular Weight ◽  
Antioxidant Capacity ◽  
High Molecular Weight ◽  
Antioxidant Properties ◽  
Intestinal Cells ◽  
Microbiological Analysis ◽  
Protective Effects ◽  
Colon Cells ◽  
Gastrointestinal Health

Background: Coffee is one of the main sources of dietary melanoidins. Coffee melanoidins have antioxidant properties and are associated with protective effects against oxidative damage. The aim of this research was to study the potential of melanoidins obtained from coffee byproducts as functional ingredients to improve gastrointestinal health using normal human colon cells. Melanoidins were extracted from two coffee byproducts: coffee silverskin (CSE) and spent coffee grounds (SCG). Extraction was carried out by ultrafiltration using a 10 kDa molecular cut membrane. Safety of raw materials and isolated fractions was studied by microbiological analysis and determination of acrylamide, respectively. Characterization of coffee isolates was assessed by UV-Vis absorption spectroscopy, infrared spectroscopy, and determination of browning, protein content and antioxidant capacity measured by ABTS and formation of intracellular ROS in human intestinal cells (CCD18 cell line). The high molecular weight (HMW) enriched fraction showed antioxidant capacity and protected intestinal cells against induced oxidative stress. Coffee byproducts generated after the roasting process are a sustainable source of melanoidins that may act as antioxidants and therefore, may have the potential to be used as a functional novel ingredient for the prevention of gastrointestinal diseases caused by oxidative stress.Keywords: Coffee byproducts, gastrointestinal health, melanoidins, sustainable health.   

scholarly journals Effects of Delayed Sample Processing on Determination of Total and High Molecular Weight (HMW) Adiponectin in Serum and Plasma: A Pilot Study

2016 ◽  
Vol 8 (3) ◽  
pp. 19
Author(s):  
Choaping Ng ◽  
Felicity J Rose ◽  
Sahar Keshvari ◽  
Marina M Reeves ◽  
Goce Dimeski ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Pilot Study ◽  
High Molecular Weight ◽  
Accurate Determination ◽  
Mean Difference ◽  
Serum Samples ◽  
Blood Samples ◽  
Hmw Adiponectin ◽  
Total Adiponectin

<p>Adiponectin is a beneficial adipocyte-secreted hormone, which circulates in a variety of multimeric forms termed low and high molecular weight (LMW/HMW). Effectiveness of clinical therapeutic trials which target adiponectin rely on accurate determination of circulating total and HMW adiponectin levels but the accuracy may be influenced by variations in sample handling processes. The aim of this pilot study was to investigate the effects of delayed processing of blood samples on the concentration of total and HMW adiponectin.</p><p>Materials and Methods: Fasting blood samples were collected for analysis of total and HMW adiponectin concentrations in EDTA plasma and serum from eight healthy participants.  Samples were centrifuged post 15 min storage at 4<sup>o</sup>C as the comparative ‘ideal’ method or after up to 72 h of refrigerated storage or 6 h at room temperature. Total and HMW adiponectin concentrations were measured by ELISA.</p><p>Results: Under ideal handling conditions measurements of total and HMW adiponectin concentrations were significantly higher in serum than in plasma (mean difference: -1.3 µg/mL [95% CI: -1.6, -1.0], p&lt;0.001; and, -0.6 µg/mL [95% CI: -0.7, -0.5], p&lt;0.001, respectively).  Storage of blood samples at 4<sup>o</sup>C for 72 h resulted in significant reductions in concentration of total adiponectin in serum (mean difference: -1.4 µg/mL [95% CI: -2.0, -0.8], p=0.001) and HMW adiponectin in plasma (mean difference: -0.6 µg/mL [95%CI: -0.9, -0.2], p=0.007), compared with ideal conditions.  Further analysis of serum samples showed a significant decrease in total adiponectin concentration after 6 h storage at 4<sup>o</sup>C (mean difference: -1.4 µg/mL [95% CI: -2.0, -0.8], p=0.001) compared with ideal conditions.</p><p>Conclusions: Delayed processing of samples may have differential effects on the concentration of total and HMW adiponectin in serum or plasma. Larger studies are warranted for clinical intervention trials.</p>

Determination of Peroxides in Synthetic Rubbers

1945 ◽  
Vol 18 (4) ◽  
pp. 874-876
Author(s):  
Richard F. Robey ◽  
Herbert K. Wiese
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Quantitative Determination ◽  
High Molecular Weight ◽  
Active Oxygen ◽  
Lower Molecular Weight ◽  
Synthetic Rubber ◽  
High Molecular Weight Polymers ◽  
Methanol Solutions

Abstract Peroxides are found in synthetic rubbers either as the result of attack by oxygen, usually from the air, or as a residue from polymerization operations employing peroxide catalysts. Because of possible detrimental effects of active oxygen on the properties of the rubber, a method of quantitative determination is needed. The concentration of peroxides in substances of lower molecular weight may be determined with ferrous thiocyanate reagent, either titrimetrically as recommended by Yule and Wilson or colorimetrically as by Young, Vogt, and Nieuwland. Unfortunately, many highly polymeric substances are not soluble in the acetone and methanol solutions employed in these procedures. This is also the case with hydrocarbon monomers, such as butadiene, containing appreciable concentrations of soluble high molecular weight polymers. Bolland, Sundralingam, Sutton and Tristram recommended benzene as a solvent for natural rubber samples and the reagent made up in methanol. However, most synthetic rubbers are not readily soluble even in this combination. The following procedure employs the ferrous thiocyanate reagent in combination with a solvent capable of maintaining considerable concentrations of synthetic rubber in solution. The solvent comprises essentially 20 per cent ethanol in chloroform.

Electrochemical determination of antioxidant properties of a series of tetraphenylporphyrin derivatives and their zinc complexes

2015 ◽  
Vol 19 (09) ◽  
pp. 1032-1038 ◽  
Author(s):  
Mariya V. Tesakova ◽  
Aleksandr S. Semeikin ◽  
Vladimir I. Parfenyuk
Keyword(s):  
Antioxidant Capacity ◽  
Antioxidant Properties ◽  
Electrochemical Determination ◽  
Zinc Complexes ◽  
Oh Groups ◽  
Electron Absorption Spectra ◽  
Before And After ◽  
Phenyl Rings ◽  
Effect Of Structure

Zinc complexes of a series of substituted tetraphenylporphyrins containing OH-groups in the phenyl rings were synthesized. Their antioxidant capacity was estimated in reaction of the porphyrins with 2,2′-diphenyl-1-picrylhydrazyl (DPPH) by cyclic voltammetry. The electron absorption spectra of the all synthesized compounds before and after the reaction with 2,2′-diphenyl-1-picrylhydrazyl were recorded. The effect of structure of the porphyrins and zinc complexes on their antioxidant capacity was discussed.

scholarly journals In Vitro Antioxidant Activity and FTIR Characterization of High-Molecular Weight Melanoidin Fractions from Different Types of Cocoa Beans

Antioxidants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 560 ◽  
Author(s):  
Oracz ◽  
Zyzelewicz
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Antioxidant Properties ◽  
Model Systems ◽  
Total Phenolic ◽  
Cocoa Beans ◽  
Potential Health ◽  
Antioxidant Power ◽  
Different Types

Melanoidins from real foods and model systems have received considerable interest due to potential health benefits. However, due to the complexity of these compounds, to date, the exact structure of melanoidins and mechanism involved in their biological activity has not been fully elucidated. Thus, the aim of this study was to investigate the total phenolic content, antioxidant properties, and structural characteristics of high-molecular weight (HMW) melanoidin fractions isolated by dialysis (>12.4 kDa) from raw and roasted cocoa beans of Criollo, Forastero, and Trinitario beans cultivated in various area. In vitro antioxidant properties of all studied HMW cocoa fractions were evaluated by four different assays, namely free radical scavenging activity against DPPH● and ABTS●+ radicals, ferric reducing antioxidant power (FRAP), and metal-chelating ability. Additionally, the structure–activity relationship of isolated HMW melanoidin fractions were analyzed using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The results show that roasting at a temperature of 150 °C and a relative air humidity of 0.3% effectively enhances the total phenolics content and the antioxidant potential of almost all HMW cocoa melanoidin fractions. The ATR-FTIR analysis revealed that the various mechanisms of action of HMW melanoidins isolates of different types of cocoa beans related to their structural diversity. Consequently, the results clearly demonstrated that HMW cocoa fractions isolated from cocoa beans (especially those of Criollo variety) roasted at higher temperatures with the lower relative humidity of air possess high antioxidant properties in vitro.

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