Guayusa tea is derived from the leaves of the Ilex guayusa Loes. plant, which is native to the Amazon rainforest. Beyond its pleasant sensory properties, Guayusa tea is rich in antioxidants, phenolics, and minerals. In this study, the effects of infusion time, temperature, and solvent conditions on the color, antioxidant capacity, total phenolic content, phenolic profile, and antimicrobial activity of Guayusa (Ilex guayusa Loes.) tea were investigated. Guayusa tea samples were prepared using two different solvents, ethanol and water, with 4, 6, and 8-h infusions at 60 and 70 °C. Liquid chromatography, diode array detection, and electrospray ionization tandem mass spectrometry (LC-DAD-ESI-MS/MS) were used to determine a comprehensive profile of phenolic compounds and to detect differences due to infusion conditions. Moreover, after the Guayusa tea infusion with the highest bioactive properties was determined, the effects of in vitro gastrointestinal digestion on the total phenolic content, antioxidant capacity, and phenolic compounds of the Guayusa tea infusion were measured. Phenolic profile analysis identified 29 compounds, among which chlorogenic acid and its derivatives were predominant. The increase in infusion time was correlated with an elevation in total phenolic content. Significant differences were observed between water and ethanol infusions of Guayusa in terms of phenolics and antioxidants. The total amount of phenolic compounds in the samples prepared with both solvents was found to increase after oral intake, depending on the digestion stage; meanwhile, the amounts of flavonoid compounds and di-O-caffeoylquinic acid derivatives decreased during digestion.

This study examined the phenolic profile, sugar composition, and antioxidant capacities of chokeberry fruits and leaves obtained from four different Turkiye provinces. A total of 21 phenolics including phenolic acid and its derivatives, flavanols, anthocyanins, and flavonols were determined in the fruits, while the leaves had 19 phenolics, including phenolic acid and its derivatives, flavanols, and flavonols. The total amount of phenolic compounds was the highest in both fruits and leaves in the samples from the Bursa province. Cis 5-O-p-coumaroylquinic acid and secoxyloganin were quantified for the first time in both fruits and leaves. In summary, it was found that different geographical locations significantly affected the phenolics, sugar contents, and antioxidant activities of the fruits and leaves.

Spirulina platensis (S. platensis) is a high-nutrient blue-green algae that has been used as a food supplement for a long time. It contains carbohydrates, lipids, proteins, vitamins, minerals, and bioactive compounds essential for basic human nutrition. It is known to have anti-cancer, antioxidant, anti-inflammatory, neuroprotective, hepatoprotective, and hypocholesterolemic properties due to the bioactive compounds it contains. In this study, the effects of freeze-thawing, a rapid freezing (-20°C) and thawing (4°C) process, and ultrasonically assisted extraction techniques on the color, antioxidant capacity, total phenolic content, and phenolic composition of Spirulina platensis extracts were investigated. The antioxidant capacity of the extracts obtained was determined by two different methods, DPPH (2,2-diphenyl-1-picryl hydrazyl) and ABTS (2,2-azinobis (3-ethylbenzothiazollin-6-sulfonic acid)). The sugar profile was determined by HPLC-RID and phenolic composition was determined by HPLC-ESI-DAD-MS/MS. The antioxidant activity and total phenolic content of samples prepared by the freeze-thawing were higher than those prepared by ultrasonic-assisted conventional extraction technique. In addition to ferulic acid 4-O-glucuronide and brevifolin carboxylate, an isocoumarin derivative, as the dominant phenolic compound in S. platensis extracts, a total of 10 phenolic compounds including catechin isomer, resveratrol C-hexoside, myricetin, ferulic acid, gallic acid, phloroglucinol, and lutein were detected. Glucose was the predominant sugar in both samples. The total sugar content was higher in the freeze-thawed samples (217.92 mg/100 g DW) than in the ultrasonic-assisted conventional extraction technique (182.91 mg/100 g DW). S. platensis has a significant amount of antioxidants, valuable secondary metabolites, and potential commercial applications and medicinal properties, but releasing these compounds is difficult due to the cell wall. This study was carried out to determine how different extraction techniques alter the release of bioactive compounds.

Black garlic is a functional food produced by processing fresh garlic under controlled temperature and humidity conditions, characterized by its rich nutritional profile. The fermentation process during production results in significant differences between black garlic and fresh garlic, particularly in phenolic compounds, antioxidant capacity, and other bioactive components. Black garlic offers various health benefits, including antioxidant, anticancer, anti‐inflammatory, immunomodulatory, antidiabetic, and cardiovascular protective effects. Furthermore, its sweet and caramelized aroma profile is appreciated by consumers for its sensory appeal. This review examines the production process of black garlic, its bioactive components, and health effects, evaluating its potential benefits as a functional food in light of scientific evidence.