This review summarizes published information concerning the determination of antioxidant activity (AA) in coffee samples by various methods (ORAC, FRAP, TRAP, TEAC, etc.) in vitro and limited data of antiradical activity of coffee products in vitro and in vivo. Comparison is carried out of the AA of coffee Arabica and coffee Robusta roasted at different temperatures as well as by different roasting methods (microwave, convection, etc.). Data on the antiradical activity of coffee is provided. The antioxidant activity of coffee, tea, cocoa, and red wine is compared. At the end of this review, the total antioxidant content (TAC) of coffee samples from 21 coffee-producing countries as measured by an amperometric method is provided. The TAC of green and roasted coffee beans is also compared.
Numerous epidemiological studies indicate that consumption of antioxidant-rich foods is beneficial to human health and reduces the risks of dangerous diseases and premature aging. Among natural antioxidants some stand out for their powerful activity and health benefits and they are epigallocatechin gallate, quercetin, curcumin, resveratrol, hydroxytyrosol, astaxanthin, lycopene, dihydroquercetin, and lignans. Preclinical, clinical, and therapeutic studies of these antioxidants in their pure form or in their combination have shown positive health benefits. This review highlights basic information and interesting findings with their source, structure, antioxidant properties, and potential health benefits to human.
This review discusses the bioavailability of active components of green and black teas--in hot brewed tea, cold tea, and dietary supplements containing tea extracts, based on literature published in 1995-2011. Many publications demonstrate that consumption of tea increases the antioxidant status of a person (between 3.5-76%) and reduces the concentration of oxidative stress biomarkers in biological fluids. In 1-2 hours after tea intake, epigallocatechin gallate (EGCG), epicatechin (EC), and epicatechin gallate (ECG) at a level of 5-150 ng/ml were detected in plasma by HPLC. The results of pharmacokinetics and metabolism of biologically active tea components analyzed within 24 hours in plasma, urine, and feces by HPLC-MS and GC-MS are presented. Dozens of metabolites were identified in urine and plasma—these are methylated, sulfated, and glucuronide conjugates of catechins. Some metabolites were shown to have high antioxidant activity. The role of the small intestine and colon in absorption of catechins was also identified.
Low-value by-products can be processed using biotechnological methods, which seems to be the optimal solution for the problem of rational use of secondary raw materials. The authors introduce a method of biotransformation using whey and enzyme preparation of proteolytic action with subsequent massaging. The method neutralizes the specific smell, reduces the time of heat treatment, increases hydrophilicity, and reduces the mechanical strength of mutton rumen tissue. The experiment proved that the enzymatic effect on the connective tissue of the mutton rumen contributes to the destruction of disulfide and hydrogen bonds of the triple helix of the collagen macromolecule. It significantly reduces the mechanical strength and hydrothermal stability of collagen, which, in its turn, reduces the heat treatment time while increasing the functional and technological properties. The research revealed an increase in collagen digestibility. After 4 hours of fermentation, it was 4.5%, after 6 hours – 5.9%, and after 8 hours – 5.9%. Hence, the optimal period of fermentation was determined as 6 hours, since between 6 and 8 hours the main physical and chemical parameters improved insignificantly. The experiment in the cutting pressure of the raw lamb rumen tissue demonstrated softening of the structure as a result of the effect of the acidic medium on the collagen structure. An excess positive charge formed due to the suppression of dissociation of carboxyl groups of side chains. The loosening of the collagen structure occurred due to the expansion of fibrils in the polar areas, which can be attributed to the repulsion between similarly charged groups. As a result, the brine penetrated into the expanded area and caused swelling. The use of whey and fermentation contributed to an additional increase in moisture-binding and moisture-holding capacity. It loosened the structure of proteins and, thus, increased the degree of penetration and the immobilized moisture in the rumen. As a result, its mass increased by 10–20%, and the heat loss reduced. The composition of the brine contributed to the swelling, increased the diameter of the collagen fibers, and enlarged the surface of interaction in during massaging. Moisture was allowed to enter freely, which increased the water binding capacity by 22.2 ± 0.31%. The increase in the water binding capacity could be explained by the modification of collagen and its destructive changes. The changes occurred due to the additional interaction of whey molecules with the protein and the formation of new intermolecular bonds. Fermentation, combined with the massaging of the tripe, contributed to the development of lactic microflora and hydrolytic decomposition of protein components, thereby reducing the heat treatment process. Such changes are associated not only with the processes of protein hydrolysis under enzyme preparation, but also with the complex activity of lactic acid bacteria, as well as endo- and exoenzymes that hydrolyze proteins. The changes can also be attributed to the fact that low-molecular protein substances can assimilate and contribute to bacterial growth. In addition, lactic acid reduces the pH of the medium, thus activating the enzymatic properties. The proposed method of biotransformation of collagen-containing raw materials makes it possible to create environmentally friendly and low-waste technologies.
Dietary polyphenols are garnering attention in the scientific community due to their potential health-beneficial properties and preventative effects against chronic diseases, viz. cardiovascular diseases, diabetes, obesity, and neurodegenerative diseases. Polyphenols are antioxidants that change microbial composition by suppressing pathogenic bacteria and stimulating beneficial bacteria. The interaction of polyphenols with dietary fibers affects their bioaccessibility in the upper and lower parts of the digestive tract. Dietary fibers, polyphenols, their conjugates, and their metabolites modulate microbiome population and diversity. Consuming polyphenol-rich dietary fibers such as pomegranate, cranberry, berries, and tea improves gut health. A complex relationship exists between polyphenol-rich diets and gut microbiota for functioning in human health. In this review, we provide an overview of the interactions of dietary polyphenols, fibers, and gut microbiota, improving the understanding of the functional properties of dietary polyphenols.
Interest in antioxidants and antioxidant therapy has been growing during the last decade.Antioxidants are generally considered to have the capability to protect people from harmful effects of reactive oxygen and nitrogen species (RONSs), including free radicals (FR), when these are present in excessive amounts.RONS and free radicals perform a variety of useful biological functions in the body.Their excess is controlled by a natural antioxidant protection system in humans.This protection is provided at three levels: by simple molecules (such as cysteine, glutathione (GSH), uric acid, ubiquinol, etc.), medium-molecular weight, and high molecular weight compounds (enzymes, etc.).Under certain adverse conditions, this system does not manage to provide adequate protection and the RONSs and free radicals begin to damage vital DNA, proteins, and lipids.In such a case, antioxidant therapy, which includes antioxidant supplements and foods containing natural antioxidants, has been suggested to be of possible benefit.However, there are many unresolved issues related to the effective use of an antioxidant therapy: 1.A person should know the content of antioxidants in everyday food products and its relation to the storage time and processing methods used.2. How many antioxidants should a person consume?It is known that at high concentrations some antioxidants become pro-oxidants.3. Are the antioxidants consumed by a person bioavailable and, if so, to what extent; for some food products, bioavailability has already been determined but most foods have not been examined.4.Many antioxidants are digested by intestinal microflora before they reach the systemic blood circulation.5.Even those antioxidants that do reach the blood are often rapidly metabolized; the role of their metabolites is unclear; there is some evidence that certain metabolites are also antioxidants.6.How long do antioxidants and their metabolites stay in the body; how are they distributed in different organs; and when are they excreted?In order to answer these questions, the pharmacokinetics of antioxidants should be studied.7. The presence of oxidative stress, i.e., excess amounts of RONSs and free radicals, can be detected by various oxidative stress markers but, in order to see the whole picture, the actual concentrations of RONSs and free radicals should also be monitored.In vivo determination of RONSs and free radicals is almost never conducted.All these questions must be addressed in order to provide appropriate antioxidant therapy.This could be extremely important because it could be used to detect and even prevent diseases at early stages of development.
Cranberries are a rich source of bioactive compounds that comprise a healthy diet. Cranberry is abundant in nutritional components and many bioactive compounds that have antioxidant properties. Both American (Vaccinium macrocarpon) and European (Vaccinium oxycoccus) cranberry species are rich in polyphenols such as phenolic acids, anthocyanins and flavonoids, and is one of the few fruits that is high in proanthocyanidins, which is linked to many health benefits. The review systematizes information on the chemical composition of cranberry, its antioxidant effect, and the beneficial impact on human health and disease prevention after cranberry consumption, and in particular, its effect against urinary tract inflammation with both adults and children, cardiovascular, oncology diseases, type 2 diabetes, metabolic syndrome, obesity, tooth decay and periodontitis, Helicobacter pylori bacteria in the stomach and other diseases. Additional research needs to study cranberry proteomics profiling, polyphenols interaction and synergism with other biologically active compounds from natural ingredients and what is important in formulation of new functional foods and supplements.
The object of research is the technological process of grain contact drying in a grain dryer with a spiral-screw transporting working organ. The aim of the study is to reduce the energy intensity of grain contact drying with the justification of constructive and regime parameters of the grain dryer. To achieve this aim, it is necessary to solve the following tasks: to develop a perspective constructive and technological scheme of a grain dryer of a contact type with a spiral-screw transporting working organ that ensures the energy intensity reduction of drying; to carry out theoretical studies of grain contact drying in a grain dryer with a spiral-screw transporting working organ; to make a prototype of a grain dryer and investigate experimentally the optimal values of constructive and regime parameters. Methods of research and equipment. As the main methods, the methods of physical modeling, multifactorial experiment and process optimization were applied. The developed grain dryer provides for reduction of the presented expenses by 60%. As the result of the research it was established that the maximum productivity is reached at 10 min-1 and is 250 kg/h. Scope of application: the farms of the agroindustrial complex of Russia.
Epidemiological studies have provided the evidence that regular consumption of fruits and vegetables reduce the risk of pathological condition such as cardiovascular disease, cancer, inflammation, and aging. Among fruits, berries are considered as superfruits due to their highly packed phytochemicals comprising phenolic acids, flavonoids viz. flavonols, flavanols, and anthocyanins. These bioactive compounds are associated with significant antioxidant, antidiabetic, antiinflammation, and anticancer properties. This review highlights the basic information and interesting findings of some selected commercial berries with their phytochemical composition, antioxidant properties, and potential health benefits to human.
