Search Results (720)

Berry skins are rich in phenolic compounds but are commonly discarded as low-value waste during berry wine production. The present study evaluated how primary alcoholic fermentation affects the retention and transformation of phenolics in berry skins of blackcurrant (Ribes nigrum L.), black chokeberry (Aronia melanocarpa L.), lingonberry (Vaccinium vitis-idaea L.), rowanberry (Sorbus aucuparia L.), and cranberry (Vaccinium macrocarpon L.). Non-fermented and fermented skin fractions were analysed using Folin–Ciocalteu and HPLC to determine total and individual phenolic profiles. Primary fermentation induced significant species-dependent changes in phenolic composition. Blackcurrant, lingonberry, and rowanberry skins exhibited substantial decreases in total phenolics (−66%, −26%, and −57%, respectively), driven by strong losses of flavan-3-ols and hydroxycinnamic acids. In contrast, cranberry and chokeberry skins showed net increases in phenolic content (+47% and +18%, respectively), associated with the release of bound phenolics and the appearance of new low-molecular-weight phenolic acids such as gallic acid. Across all species, fermentation enhanced biotransformation into simpler phenolics while reducing major native anthocyanins and catechins. These results demonstrate that the influence of primary fermentation on berry skins is not uniform but dictated by their inherent phenolic architecture. Berries rich in polymeric or conjugated phenolics benefit from fermentation through increased phenolic extractability. The findings provide a comparative basis for optimizing fermentation and post-processing strategies to enhance the valorization potential of berry by-products in food and nutraceutical applications. Full article

This study investigated the effects of thermal processing and extraction solvents on the phytochemical composition, antioxidant potential, and cytotoxic activity of Sukhothai fragrant rice (Oryza sativa L.). Rice subjected to three processing methods, unprocessed (raw), popped/puffed and steam-cooked, was extracted using hot water or 70% (v/v) ethanol, yielding six extracts. Trans-ferulic acid, γ-oryzanol and anthocyanins were quantified using HPLC-DAD and HPLC-ESI-MS, while total phenolic and flavonoid contents, and antioxidant activities were evaluated using Folin–Ciocalteu, aluminium chloride, DPPH and ABTS assays. Cytotoxicity was assessed in Huh7 hepatocellular carcinoma cells. Water extracts consistently produced higher yields and contained greater total phenolic, flavonoid and anthocyanin contents, resulting in stronger antioxidant activity. Unprocessed rice water extract exhibited the highest trans-ferulic acid recovery and antioxidant capacity. Thermal processing, particularly steamed cooking, markedly reduced phytochemical contents, likely due to heat-induced degradation. In contrast, ethanolic extracts yielded lower quantities but higher concentrations of less polar bioactive compounds and exhibited greater cytotoxic effects. Overall, minimal thermal processing combined with aqueous extraction best preserved antioxidant compounds, while ethanolic extraction enhanced biological potency. These findings highlight the importance of processing intensity and solvent polarity in optimizing the nutraceutical and functional potential of black rice. Full article

Polyphenols, particularly anthocyanins, are associated with metabolic health benefits; however, whether anthocyanin extracts provide greater bioaccessibility than whole foods remain unclear. This study investigated the role of the food matrix in açaí berry, one of the richest natural sources of anthocyanins, by comparing polyphenol and anthocyanin bioaccessibility across freeze-dried whole fruit, crude extract, and purified extract. All samples underwent standardised INFOGEST in vitro digestion, and total polyphenol content (TPC), anthocyanins (ACN), and antioxidant activity were quantified using Folin–Ciocalteu, pH-differential, and DPPH assays, respectively. Intestinal-phase TPC % bioaccessibility was similar in whole fruit (58%) and crude extract (58%) but significantly lower in pure extract (43%). ACN bioaccessibility showed a pronounced matrix effect, with the highest retention in whole fruit (44%), followed by crude extract (32%), and the lowest retention in pure extract (12%). Antioxidant activity after intestinal digestion mirrored these patterns. Overall, these findings demonstrate that the natural açaí food matrix substantially preserves anthocyanin stability during digestion, resulting in higher bioaccessible levels than matrix-free extracts, suggesting that incorporating matrix components into anthocyanin-rich nutraceuticals may help support greater functional recovery during gastrointestinal digestion. Full article

Macroalgae are increasingly recognized as a valuable source of nutrients and bioactive compounds for animal nutrition, including for aquatic species. However, the complex structure of the macroalgal cell wall limits the accessibility of intracellular components, restricting their use in feeds. To overcome this limitation, macroalgal hydrolysis using various technological treatments has been tested, often employing a low solid-to-water ratio, which complicates downstream processing due to phase separation. In contrast, high-solids loading hydrolysis has the advantage of producing a single and consolidated fraction, simplifying subsequent processing and application. The present study assessed the effectiveness of high-solids loading water or alkaline (0.5 and 1N NaOH) autoclaving for 30 or 60 min, applied alone or followed by sequential enzymatic hydrolysis, using a xylanase-rich enzymatic complex aimed at promoting cell wall disruption and increasing the extractability of intracellular components in the red macroalga Palmaria palmata with minimal free water. The 1N NaOH treatment for 30 min decreased neutral and acid detergent fiber while increasing Folin–Ciocalteu total phenolic content (GAE) (expressed as gallic acid equivalent) and the water-soluble protein fraction and decreased crude protein, indicating enhanced extractability of these components. Microscopic examination showed relatively mild structural changes on the surface of P. palmata after high-solids loading alkaline (1N NaOH) autoclaving for 30 min. Following alkaline or water treatment, the enzymatic complex hydrolysis further increased the Folin–Ciocalteu total phenolic content (GAE), with minimal effects on NDF, ADF, or crude protein. Overall, these results showed that high-solids loading alkaline autoclaving, with or without subsequent enzymatic hydrolysis, effectively disrupts P. palmata cell walls and induces substantial modifications while simplifying processing by avoiding phase separation. Full article

Oak (Quercus spp.), traditionally used for aging alcoholic beverages, is not native in many countries, which increases production costs and environmental impact. During the aging process of alcoholic beverages, complex physical and chemical transformations occur that determine their chemical composition and sensory quality, many of which are unique depending on the type of wood used in the process. In this context, Maclura tinctoria (Tajuva), a native Brazilian species rich in phenolic compounds, was evaluated based on its phenolic composition and extraction behavior as a sustainable alternative for beverage aging. Wood chips were subjected to three toasting levels (untoasted, medium, and high) and aged for up to 360 days in two hydroethanolic model systems (10% and 14% v/v ethanol). The total and individual phenolic compounds were determined using the Folin–Ciocalteu method and HPLC–DAD/LC–MS/MS analysis. Results showed that toasting level, ethanol concentration, and aging time significantly influenced phenolic extraction. Untoasted Tajuva released the highest amounts of phenolic acids and flavonoids, particularly gallic and caffeic acids, and quercetin, respectively; while medium toasting favored the formation of thermally derived aromatic compounds, such as vanillic acid. The 14% ethanol system enhanced extraction efficiency for most analytes. Overall, Tajuva wood exhibited higher phenolic yields than French oak under comparable conditions, highlighting its chemical richness and extraction reactivity. These findings support the use of M. tinctoria as an eco-efficient and functional alternative to oak for the maturation of alcoholic beverages. Full article

Olive mill wastewater (OMW) contains high organic loads and phytotoxic polyphenols. In Tunisia, OMW is often stored in unlined evaporation ponds. This practice creates a risk of soil and groundwater contamination. This study evaluates the environmental impact of a long-term OMW evaporation pond in the Ben Aoun area, Sidi Bouzid region. The investigation combines wastewater, soil and groundwater sampling with laboratory physicochemical analyses. Three OMW samples (E1 surface, E2 mixed, E3 recent spill) were collected. Three shallow boreholes (0–5 m) were sampled at 20 cm intervals. In addition, three nearby pumping wells were sampled. All samples were analyzed for pH, electrical conductivity (EC), chemical oxygen demand (COD), total and volatile solids, major cations/anions, total nitrogen, total phosphorus and total polyphenols. Results obtained using the Folin–Ciocalteu method are expressed as mg Eq AG L⁻¹ for liquids and mg Eq AG gMS⁻¹ for soils. OMW samples showed high COD (E1 = 48, E2 = 70, E3 = 80 g/L) and polyphenols (E1 = 5, E2 = 9.7, E3 = 14 g/L). Soil profiles inside the pond exhibited increased EC with peak of 15.48 mS cm⁻¹ at 0.4 m depth. Near-surface layers showed low pH and increased organic matter and polyphenols to depths of ~5 m. Groundwater samples collected near the pond contained measurable polyphenols (up to 41 mg/L in the closest well), indicating subsurface migration. Evidence indicates lateral migration of about 20 m and vertical infiltration to a depth of approximately 5 m beneath the pond. The findings demonstrate that unlined OMW evaporation ponds act as a persistent source of organic and phenolic contamination. This poses a potential risk to shallow groundwater. Full article

Tiger nut (Cyperus esculentus L.) is a relatively neglected tuber crop with notable nutritional, functional, and ecological value. The primary objective of this study was to evaluate the biological properties and selected nutritional parameters of tiger nut tubers and oil, including antioxidant activity, total phenolic content (TPC), fatty acid (FA) profile, health-related lipid indices, and mineral composition. Methods: Natural and peeled tiger nut tubers, as well as commercially available tiger nut oil (yellow variety, Valencia, Spain), were analyzed. Antioxidant activity was measured spectrophotometrically using the DPPH method. The content of TPC was determined using the Folin–Ciocalteu assay. Fatty acid composition was analyzed by gas chromatography coupled with flame ionization detection, and these data were used to calculate the PUFA/SFA (P/S) ratio, atherogenicity (AI), thrombogenicity (TI) index, and hypocholesterolemic/hypercholesterolemic (h/H) ratio. Macro- and microelement contents were quantified using inductively coupled plasma optical emission spectrometry. Estimated daily intake (EDI), target hazard quotient (THQ), and total THQ (TTHQ) were calculated to assess potential health risks. Results: Natural tiger nut tubers exhibited substantially higher antioxidant activity and TPC compared to peeled tubers, suggesting that the peel is the primary reservoir of phenolic compounds. Strong antioxidant activity was observed in tiger nut oil (64.82 ± 2.59 mg TEAC/L). Oleic acid (C18:1cis n-9) was identified as the predominant FA across all samples, thus contributing positively to favorable health lipid indices (P/S > 0.50, low AI and TI, high h/H ratio). Potassium was the most abundant macroelement in natural and peeled tiger nut tubers. The overall trend of microelement levels in these samples was as follows: Al > Fe > Zn > Cu > Sr > Mn > Li > Ba > Se > As > Cr. All THQ and TTHQ values were below 1, indicating no appreciable health risk associated with consumption. Conclusions: These findings support the use of tiger nuts as a functionally valuable ingredient in health-oriented food products. Full article

Kombucha is a millennia-old beverage crafted from green or black tea and saccharides and fermented with a symbiotic culture of bacteria and yeast (SCOBY). This functional drink boasts health benefits, such as improved intestinal flora function, hepatoprotection and inhibition of amyloid fibers. It contains bioactive antioxidants, such as catechins, ascorbic acid, vitamins and other polyphenolic compounds. With kombucha’s rising popularity, the Food and Drug Administration (FDA) has implemented control procedures to ensure the quality and safety of this food product. Due to the antioxidant properties of the major bioactive compounds in kombucha, feasible and low-cost electroanalytical methods emerge as promising alternatives. The objective of this study was to evaluate the voltammetric behavior of kombucha samples to establish and compare their redox profiles and antioxidant activities. Thus, 18 kombucha samples were used, comprising commercial samples and samples prepared in the laboratory from different SCOBYs purchased from different countries, and analyzed by differential pulse voltammetry (DPV) and square wave voltammetry (SWV) on a carbon paste electrode (CPE). The electrochemical index (EI) values determined from the samples were used to establish their antioxidant activities. The EI values were also compared with spectrophotometric data from Folin–Ciocalteu (FC) and Ferric Reducing Antioxidant Power (FRAP) assays. Full article

Salvia dumetorum Andrz. ex Besser is a promising non-pharmacopoeial plant species with traditional medicinal potential. This study aimed to determine the optimal microwave-assisted extraction (MAE) conditions for obtaining a polyphenol-rich ethanolic extract from the S. dumetorum leaves. Dried and powdered leaves were extracted using 40% ethanol with different power of microwaves varying from 200 to 800 W and time of extraction 2–8 min. The extract was filtered, concentrated, and evaluated for yield, identification of phenolic compounds using high-performance liquid chromatography (HPLC), total phenolic content (TPC), and total flavonoid content (TFC). Extraction yields ranged from 2.20% to 25.80% based on dry weight. TPC and TFC were determined using Folin–Ciocalteu and aluminum chloride colorimetric assays, respectively, and are expressed as mg GAE/g and mg RUE/g of dry extract. The antioxidant activity of the extracts was evaluated using the DPPH (2,2-diphenyl-1-picrylhydrazyl radical) assay. According to HPLC analysis, the main phenolic components of the extracts were rosmarinic acid (1.78–2.95 mg/mL), chlorogenic acid (0.31–0.54 mg/mL), caffeic acid (0.11–0.20 mg/mL), rutin (up to 0.47 mg/mL) and ferulic acid (0.13–0.33 mg/mL); traces of myricetin were found only in isolated samples. The optimum extraction conditions were found to be 400 W microwave power, 8 min extraction time, one MAE cycle, and a 1:30 g/mL solvent-to-material loading ratio; TPC and TFC were evaluated as 35.23 ± 0.50 mg GAE/g DW and 19.94 ± 0.14 mg RuE/g DW, respectively, indicating the highest yield of polyphenolic compounds, antioxidant potential inhibiting 96.68% ± 0.27 of DPPH radicals, and IC₅₀ = 10.24 µg/mL. These findings highlight the efficiency of MAE in producing a bioactive ethanolic extract of S. dumetorum, which can be further explored for potential applications as a natural antioxidant in pharmaceutical or cosmetic formulations. Full article

Agro-industrial by-products are rich in polyphenols with potential applications as natural antimicrobials in food systems. This study evaluated the total polyphenol content (TPC) and antimicrobial activity of orange (Citrus sinensis), onion (Allium cepa), cacao (Theobroma cacao), and tamarillo (Solanum betaceum) peel extracts against Listeria monocytogenes, individually and in combination with Saccharomyces cerevisiae. TPC was quantified using the Folin–Ciocalteu method, and minimum inhibitory concentrations (MICs) were determined using broth microdilution. Statistical analysis (two-way ANOVA, p < 0.05) assessed the effect of extract type and yeast addition on MIC values. The highest TPC was recorded in Theobroma cacao peel extract (85.3 ± 2.1 mg GAE/g DW). All extracts inhibited L. monocytogenes, with MICs ranging from 2.5 to 10 mg/mL. This was reduced to 1.25–5 mg/mL when combined with S. cerevisiae, indicating synergism (F = 11.42, p = 0.003). These results suggest that polyphenol-rich peel extracts enhanced by S. cerevisiae can be incorporated into beverage preservation systems, aligning with clean-label trends. This study integrates quantitative and mechanistic analyses to link extraction methods, polyphenol content, and synergistic inhibition with Saccharomyces cerevisiae, providing a coherent analytical framework for sustainable antimicrobial strategies. Full article

Sustaining irrigated agriculture under drought conditions with alternative water sources such as saline groundwater requires understanding their effects on salt-tolerant crops like pistachio. During recent California droughts, pistachio trees planted in 2002, 2009, and 2011 were irrigated with high-saline water containing traces of boron (B) and selenium (Se). In 2018, irrigation was divided so that half of the trees received low-saline water, while the others continued under high-saline irrigation. Three years later, nuts were harvested to evaluate how irrigation quality affected seed coats, the main storage site of phenolic antioxidants. Sixty seed coat extracts from both irrigation treatments were analyzed for antioxidant capacity (ABTS, DPPH, FRAP and Folin–Ciocalteu assays). Nuts from the oldest trees (planted in 2002) had the highest antioxidant capacity. High-performance liquid chromatography (HPLC) identified gallic acid and nine flavonoids. Catechin, procyanidin B1, cyanidin-3-O-galactoside, and eriodictyol were most abundant in the oldest trees. Irrigation salinity significantly affected gallic acid, quercetin, and isoquercetin, with higher concentrations detected in seed coats from trees receiving continued high-saline irrigation. These compound-specific shifts, together with strong age-dependent patterns, provide insight into how long-term salinity exposure influences phenolic composition in pistachio seed coats. Full article

The objective of this study was to evaluate the radical scavenging activity (RSA) and total polyphenolic content (TPC) in petiolate vegetables (baby spinach) and sessile vegetables (Romaine lettuce) disinfected with essential oils of thyme and peppermint compared with bleach solutions, a chemical disinfectant widely used in food preparation. The vegetables, obtained from local markets in Granada (Spain), were treated with varying concentrations of essential oils and bleach solutions. Antiradical activity was evaluated using the DPPH radical scavenging method, while total polyphenols were determined using the Folin–Ciocalteu reagent. The results showed that essential oils significantly reduced microbial load, with inverse correlations between radical scavenging activity and microbial load and total phenolic compounds. Bleach solutions, on the other hand, show a strong direct correlation, significantly reducing the microbial load as well as the antiradical activity and total phenolic content. However, this antimicrobial and antioxidant effect depends on the morphological characteristics of the vegetable (stemmed or sessile) and the chemical composition of the essential oil. These results suggest that essential oils may be effective natural alternatives for disinfecting vegetables, as they increase their antiradical activity and polyphenolic content, in contrast to sodium hypochlorite, which affects the functional properties of the product by reducing the RSA and TPC. Full article

This study aimed to develop an efficient and environmentally sustainable method for extracting bioactive compounds from juçara palm (Euterpe edulis Mart.) fruit residues using deep eutectic solvents (DES) and conventional solvents, combined with ultrasound-assisted extraction (UAE). Seven DES formulations based on choline chloride (ChCl) and different hydrogen bond donors (glycerol, glucose, and organic acids) were prepared, and their performance was compared with water, ethanol, and ethanol/water mixtures. The phenolic composition, anthocyanins and antioxidant activity of the extracts were determined using spectrophotometric assays (Folin–Ciocalteu, DPPH, ABTS, and FRAP) and ESI–MS/MS analysis. The results showed that DES exhibited higher efficiency in recovering total phenolic compounds, anthocyanins and ABTS compared to conventional solvents, particularly in the ChCl–glycerol system. ESI–MS/MS analyses monitored around 40 phenolic compounds, including phenolic acids, flavanones, flavonoids, and anthocyanins. Acidic solvents favored anthocyanin extraction and stability, while ethanol- and glycerol-based systems provided broader compound profiles. The use of DES proved to be a green and selective alternative for obtaining extracts rich in bioactive compounds, enhancing the value of juçara residues and contributing to the sustainability of the species production chain. Full article

One of the approaches to increase bioavailability and stability of hydrophobic biologically active compounds is their incorporation into polymer backbone. This work deals with the modification of chitosan (CS) with gossypol (GS), a phenolic compound with confirmed anticancer properties, by the free-radical grafting method. The series of the CS derivatives with increasing content of GS were prepared using pure GS or gossypol acetate (GSA) and compared to the control CS (cCS). The starting CS, cCS, and GS-containing derivatives were characterized using Fourier-transform infrared (FTIR), Raman, and ¹³C ssNMR spectroscopies; elemental and thermogravimetric analysis to evaluate the influence of the radicals and GS on the properties of polymers was performed. The Folin–Ciocalteu (F-C) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods were used to evaluate antioxidant properties of GS-modified CSs. Additionally, the polymer solubility and the specific viscosity of the solutions were determined. The content of GS in polymers raised proportionally with increasing amount of GS added to the reaction mixture, thereby enhancing the ability to scavenge free radicals. The type of GS used (GS or GSA) in polymers affected the degree of CS crosslinking (higher for pure GS), polymer solubility (lower for pure GS), the amount of grafted GS (~20% higher for GSA), and antioxidant properties in favor of GSA. Full article

The increase in pineapple production has led to a significant accumulation of agro-industrial waste, underscoring the need for sustainable strategies for its utilization. The valorization of pineapple crowns presents an opportunity to produce value-added products rich in phenolic compounds, thereby reducing environmental impacts and offering accessible alternatives to small-scale producers. Among the methods for extracting phenolic compounds, maceration, Soxhlet extraction, and fermentation stand out, with the latter being considered a low-cost and more environmentally sustainable option. In this study, the objective was to compare three extraction methods (dynamic maceration, Soxhlet extraction, and fermentation) were compared to identify the most efficient method for recovering phenolic compounds from pineapple crowns. The results showed that fermentation yielded the highest total phenolic compounds of 82.3 mg GAE/g (Folin–Ciocalteu) and 64.1 mg GAE/g (Fast Blue BB), followed by maceration at 17.3 mg GAE/g (Folin–Ciocalteu) and 10.2 mg GAE/g (Fast Blue BB) and Soxhlet extraction at 2.1 mg GAE/g for both, with gallic, ferulic, and p-coumaric acids being particularly noteworthy in the fermented extract. The microorganism Bacillus sp. SMIA-2 played a significant role in the release and availability of these compounds, increasing the efficiency of the process. Thus, fermentation proves to be a sustainable and economically viable alternative for utilizing pineapple crowns, promoting the rational use of plant biomass and adding value to a low-cost, easily applicable agro-industrial byproduct. Full article