It is well known that carbohydrates are the main source of calories in most diets. However, by inhibiting carbohydrases, intake of calories is reduced and weight loss is improved. α-amylase is an enzyme that hydrolyses α-1,4 glycosidic linkages of α-linked polysaccharides, resulting in low-molecular-weight products such as glucose, maltose and maltotriose, while α-glucosidase catalyzes the hydrolysis of nonreducing α-1,4-linked glucose moieties from disaccharides or oligosaccharides. Currently, one of the most common nutritional disorders in the world is hyperglycemia. One of the new therapeutic approaches to treat this disease is the application of natural inhibitors, such as polyphenols, that control starch digestion and regulate blood glucose level. Dietary polyphenols showed potential inhibitory activity against α-amylase and α-glucosidase and this review summarizes the recently published literature that studied inhibition mechanisms and the structure–activity relationship between individual dietary polyphenols and mentioned digestive enzymes. It is known that higher binding interactions cause higher inhibitory activities; thus, different polyphenols can affect different steps in the digestion of polysaccharides. The aim of this review is to clarify these mechanisms and to introduce polyphenol-rich functional foods as potential tools for the inhibition of α-amylase and α-glucosidase.

Polyphenols are secondary plant metabolites synthesized during the development of the grape berry as a response to stress conditions. They are important constituents in red wines that contribute to the sensory properties and antioxidant activity of wines. Due to the development of highly sophisticated analytical devices, it is now possible to characterize the structure of highly polymerized polyphenols and obtain a full polyphenol profile of red wines. Red wine polyphenols include the ones present in grapes as well as new polyphenol products formed during the winemaking process. Among them, the most important groups and their representatives are flavanols (catechin), stilbenes (trans-resveratrol), flavonols (quercetin) and hydroxybenzoic acids (gallic acid). It is known that polyphenols exhibit beneficial effects on human health, such as anti-inflammatory, anticarcinogenic and cardio-protective effects. Many studies have been conducted on the health effects of red wine polyphenols in cancer chemopreventive activities, neuroprotective effects and impact on cardiovascular diseases, gut microbiota in humans, etc. This review will provide major scientific findings on the impact of red wine polyphenols on human health as well as a review of polyphenols present in red wines and their main features.

Chocolate production is a complex process during which numerous chemical reactions occur. The most important processes, involving most of the reactions important for development of the proper chocolate flavor, are fermentation, drying and roasting of cocoa bean, and chocolate conching. During fermentation, formation of important precursors occurs, which are essential for further chemical reactions in the following processes of chocolate production. Roasting is one of the most important processes due to the occurrence of Maillard’s reactions, during which aroma compounds are formed. In this paper, we have reviewed the most important chemical reactions that occur with proteins, carbohydrates, lipids, and polyphenols. Additionally, we present other components that may be naturally present or form during the production process, such as methylxanthines, aldehydes, esters, ketones, pyrazines, acids, and alcohols.

Polyphenols have received great attention as important phytochemicals beneficial for human health. They have a protective effect against cardiovascular disease, obesity, cancer and diabetes. The utilization of polyphenols as natural antioxidants, functional ingredients and supplements is limited due to their low stability caused by environmental and processing conditions, such as heat, light, oxygen, pH, enzymes and so forth. These disadvantages are overcome by the encapsulation of polyphenols by different methods in the presence of polyphenolic carriers. Different encapsulation technologies have been established with the purpose of decreasing polyphenol sensitivity and the creation of more efficient delivery systems. Among them, spray-drying and freeze-drying are the most common methods for polyphenol encapsulation. This review will provide an overview of scientific studies in which polyphenols from different sources were encapsulated using these two drying methods, as well as the impact of different polysaccharides used as carriers for encapsulation.

Complex challenges are facing the food industry as it develops novel and innovative products for the consumer marketplace. Food processing and preservation are primarily based on achievement and maintenance of safety in order to protect consumers, as well as extending product shelf life under the relevant conditions of storage, transport and distribution. Maximizing retention of bioactives with recognized positive effects on health typically comes under consideration when the previous two priorities have been achieved. This review introduces the potential applications of hydrogels as delivery systems of high-value bioactives like phenolics and aromas. If they are successfully encapsulated within the gel structures, their release can be controlled, which opens a wide range of applications, not only in food, but also in the pharmaceutical and cosmetic industries. Hydrogels are three-dimensional network structures which can absorb significant amounts of water. They have the ability to thicken the system and therefore can be used to design products with desired properties. In order to preserve the valuable components, it is necessary to know their physicochemical properties, in addition to the properties of the polymer used for hydrogel preparation.

Green, black and yellow tea leaves are rich in phenolic compounds that are known for their antioxidant activity thus beneficial effect on human health. In practice, different methods are used to determine antioxidant activity. The objective of this study was to determine content of phenols, flavonoids and tannins, as well as antioxidant activity of tea leaves.