Coffee is one of the most often consumed beverages almost all over the world. The multiplicity of beans, as well as the methods and parameters used to brew, encourages the optimization of the brewing process. The study aimed to analyze the effect of roasting beans, the brewing technique, and its parameters (time and water temperature) on antioxidant activity (determined using several in vitro methods), total polyphenols, flavonoids, and caffeine content. The infusions of unroasted and roasted Arabica beans from Brazil, Colombia, India, Peru, and Rwanda were analyzed. In general, infusions prepared from roasted beans had higher antioxidant activity and the content of above-mentioned compounds. The hot brew method was used to obtain infusions with a higher antioxidant activity, while the cold brew with higher caffeine content. The phenolic compound content in infusions prepared using both techniques depended on the roasting process. Moreover, the bean’s origin, roasting process, and brewing technique had a significant effect on the tested properties, in contrary to brewing time and water temperature (below and above 90 °C), which had less impact. The results confirm the importance of coffee brewing optimization.

Summary: Introduction: Hop (Humulus lupulus L.) is a common plant in Europe, with many beneficial health effects. In addition to the use in brewing, hops are a valuable source of active substances used in conventional and folk medicine, such as humulones and lupulones, as well as antioxidants, including phenolic compounds. Objective: The aim of the study was to evaluate and compare the antioxidant activity of alcoholic extracts of fresh hop leaves collected in 2017 and 2018. Material and methods: The raw material consisting of fresh hop leaves was extracted using ultrasound-assisted extraction. Methyl, ethyl and isopropyl alcohol at three concentrations were used as extractants. The antioxidant activity of extracts was determined using DPPH and FRAP methods. Total phenolic content was evaluated using the Folin-Ciocalteu technique. Results: All the extracts showed antioxidant potential as well as the phenolic content. Regardless of the harvesting year and methods of evaluation, the highest antioxidant activity and the total polyphenol content were observed for extracts prepared in undiluted methanol, obtained during one hour lasting extraction. Conclusion: The results of the studies have suggested that hop leaves can be a potential source of health-promoting antioxidants.

The diet rich in fruits is widely recommended for health-promoting properties. Regular consumption of fruits could reduce the risk of many diseases. The fruit-based alcoholic beverages have been produced for centuries and, in many countries, are still very popular. ‘Nalewka’ is a traditional name of Polish liqueur, i.e., an alcoholic beverage made by maceration of fruits. Homemade nalewkas are often stored for a long time before consumption, which can affect the content of valuable secondary metabolites. The aim of the study was to compare the effect of long-time storage on antioxidant activity and total polyphenol, total anthocyanin, tannin as well as gallic acid content in three homemade nalewkas. Cherry, plum, and multifruit nalewka were produced in 1997 and between 2013–2019 years. The antioxidant activity was measured by the DPPH, ABTS, FRAP, and CUPRAC methods. The content of gallic acid was estimated by high-performance liquid chromatography (HPLC). The oldest nalewkas (from 1997) showed significantly lower antioxidant activity as well as a lower content of polyphenols, anthocyanins, and gallic acid compared to the later-produced nalewkas, in particular those produced in 2016–2019. In most cases, a correlation was also found between the parameters of antioxidant activity as well as the total content of polyphenols and anthocyanins. Long-term storage of nalewkas reduces the content of valuable secondary metabolites responsible for the antioxidant activity and, thus, the health properties of the beverage.

Summary: Introduction: Quince (Cydonia oblonga Mill.) is a plant of which both the fruits and the leaves are sources of compounds with antioxidant potential. Such activity could be helpful to prevent the development of so-called oxidative stress. Objective: The aim of the study was to evaluate the antioxidant properties of ethanolic, methanolic and acetonic extracts of mature and immature quince fruits, as well as leaves. Methods: The extracts were prepared using ultrasound-assisted extraction, for 15, 30 and 60 minutes. The antioxidant activity was assessed by DPPH, FRAP, ABTS and Folin-Ciocalteu (F-C) methods. Results: Antioxidant activity of all of the evaluated extracts were observed. The highest potential determined with each method was found for leaf extracts. Moreover, higher activity of unripe fruit extracts compared to ripe fruit was observed. Taking into account the applied extractants, the highest antioxidant capacity was found for methanolic extracts, extracted for 60 and 30 minutes. By contrast, the lowest potential was observed mainly for ethanolic extracts (extraction time 15 minutes). Conclusion: Quince extracts, particularly alcoholic extracts of leaves, seem to be a valuable source of anti-oxidants. Factors as extraction time, the type of solvent and degree of fruit maturity may influence the antioxidant activity of extracts.

The study aimed to evaluate the phytochemical profile (flavonoids, phenolic acids, caffeine, vitamin C, and acetic acid), in vitro antioxidant potential, total polyphenol and flavonoid content, as well as the pH of eight green tea-based kombuchas.

The aim of the present study was to determine the antioxidant activity of the aqueous extracts from Lycopodium clavatum, Cetraria islandica and Dipsacus fullonum obtained using aqueous solutions of ionic liquids by the ultrasound-assisted extraction (IL-UAE) method. Triethanolammonium salts [TEAH]⁺[AA]⁻ of four amino acids of different hydrophobicity – isoleucine – Ile, methionine – Met, threonine – Thr and arginine – Arg, were chosen as ionic liquids, because they are based on natural, bio-renewable raw materials, such as amino acids and contain a pharmaceutically and cosmetically acceptable counterion of triethanolamine. Triethanolammonium salts were synthesized, identified by spectroscopic methods (NMR and FT-IR) and characterized by thermal methods (DSC and TGA). The 2.5% w/v aqueous solutions of triethanolammonium amino acid salts were used as the solvents in combination with ultrasound assisted extraction (UAE). The estimation of antioxidant properties was carried out using the DPPH, FRAP and CUPRAC assays. Total polyphenol content was measured using the reagent Folin–Ciocalteu. The results showed that the use of [TEAH]⁺[Thr]⁻ or [TEAH]⁺[Met]⁻ aqueous solutions increased the antioxidant activity of extracts in comparison to that achieved for extracts with pure water. The use of [TEAH]⁺[Thr]⁻ as an additive for ultrasound-assisted extraction was characterized by obtaining plant extracts with the highest antioxidant potential, even 2.4-fold. The use of the AAIL-UAE method allowed obtaining higher amounts of polyphenols compared to pure water extracts, even 5.5-fold. The used method allowed the extraction of thermosensitive natural compounds, shortened the extraction time and lowered energy consumption.